Chapter 3: Drug Administration
2 Contact Hours
By: Katie Ingersoll, RPh, PharmD
Author Disclosure: Katie Ingersoll and Elite do not have any actual or Questions regarding statements of credit and other customer service potential conflicts of interest in relation to this lesson. issues should be directed to 1-888-666-9053. This lesson is $12.00. Universal Activity Number (UAN): 0761-9999-17-079-H01-P Educational Review Systems is accredited by the Activity Type: Knowledge-based Accreditation Council of Pharmacy Education (ACPE) Initial Release Date: April 1, 2017 as a provider of continuing pharmaceutical education. Expiration Date: April 1, 2019 This program is approved for 2 hours (0.2 CEUs) of Target Audience: Pharmacists in a community-based setting. continuing pharmacy education credit. Proof of participation will be posted to your NABP CPE profile within 4 to 6 To Obtain Credit: A minimum test score of 70 percent is needed weeks to participants who have successfully completed the post-test. to obtain a credit. Please submit your answers either by mail, fax, or Participants must participate in the entire presentation and complete online at Pharmacy.EliteCME.com. the course evaluation to receive continuing pharmacy education credit.
Learning objectives After completion of this course, healthcare professionals will be able Discuss the administration of medications in patients using enteral to: and parenteral nutrition. Describe the eight rights of medication administration. Discuss special considerations for administering medications in Explain the administration of enteral and parenteral medications. pediatric and geriatric patients. Introduction Medication errors that occur at the point of drug administration poised to reduce the frequency of medication administration errors. comprise a significant portion of the errors that can occur in the Understanding medication administration and putting best practice medication use process. As healthcare providers with a wealth of standards in place will help reduce medication administration errors knowledge on the use of medications, pharmacists are perfectly and increase patient safety.
Preventing medication errors during drug administration: The eight rights of medication administration The eight rights of medication administration are used to help ensure The right time all the necessary information is verified in order to administer a Before administering a medication, the provider must confirm that the medication appropriately. Historically, healthcare professionals were prescription is written for the correct time of day and frequency, and taught the five rights of medication administration: right drug, right that the scheduled administration time matches up with the prescriber’s patient, right dose, right time, and right route. However, an updated order. listing includes three more: right reason, right response, and right The right route documentation. These eight practices are essential to the safe and The route by which the medication will be given must be documented accurate administration of medications. on the prescription, and verified to ensure it is appropriate for the The right drug patient to whom it will be administered. On receipt of a prescription order, it is imperative that the correct The right reason medication is selected for administration to the patient. If the name The reason for administering a particular medication should be of the drug is unfamiliar, the provider administering the medication confirmed to make sure that the prescribed drug is appropriate for the should consult a reliable reference to ensure the correct medication is patient’s condition. Common conditions the drug is used for should used. If necessary, the provider should consult references to identify be crosschecked against the patient’s conditions to make sure the the purpose of administering the drug, its action, routine routes and medication is given for an appropriate reason. doses, interactions with other drugs, herbs, and foods, side effects, and contraindications. When selecting the medication, the provider should The right response check the medication label to ensure accuracy. The patient’s response to the drug must be monitored. Pharmacy staff should communicate with physicians or nurses to ensure they The right patient are aware of the desired response and the desired response should be The patient’s identity must be confirmed by checking two patient communicated to the patient as part of providing patient counseling. identifiers, including name, date of birth, address, or medical record number. Any inconsistencies should be verified before medication The right documentation administration. Documentation and record keeping are essential. Documentation of what was administered to the patient as well as any patient education The right dose that was provided should be maintained(1)(2). The healthcare provider must confirm that the dose is appropriate for the drug, the condition, and the patient. The dose being administered should be crosschecked with the medication’s label to make sure the correct dose will be administered to the patient.
Page 36 Pharmacy.EliteCME.com Routes of administration Routes of administration for drugs can be classified into two concentrations, the desired effect must be taken into consideration categories: enteral or parenteral. Medications that are administered when choosing a medication’s route of administration. For example, through the enteral route are absorbed in the digestive tract. This hormone replacement therapy with estrogen can be administered can apply to any part of the digestive tract, from the mouth to the through several routes of administration, but the desired effect and rectum. The common enteral routes of administration are oral, buccal, potential side effects must be carefully considered before choosing a sublingual, and rectal. dosage form. Some women prefer to use oral treatments due to their Drug administration that bypasses the digestive tract is considered a desired systemic effects. Other women, such as women with estrogen- parenteral route of administration. Parenteral routes are used in many related cancers, must avoid systemic dosage forms, so vaginal circumstances, including when the patient’s gastrointestinal tract is not preparations are used to minimize systemic effects. functioning, rapid effects are desired, or the patient is unconscious. The patient’s condition must also be carefully considered when There are many parenteral routes of administration; the most common choosing a route of administration. Pediatric and elderly patients are are intravenous, intramuscular, and subcutaneous. particularly susceptible to medication administration errors due to their Medications are often formulated in several different dosage forms, vulnerable conditions. The use of multiple medications and enteral or to be administered by various routes. Since the various dosage forms parenteral nutritional support must also be taken into consideration can result in differing durations of action, onset times, and drug when medications are administered.(1)
Enteral routes of administration: Oral The oral route is the most commonly used route of medication can be compromised when the patient is nauseous or vomiting. The administration, since oral dosage forms are portable and easy to acidic gastric secretions of the stomach also have the potential to administer. Oral medications are economical, because they do not destroy certain drugs, and irritating medications combined with gastric require sterile preparation and are available in inexpensive forms. acid can cause nausea and vomiting in some patients. Orally administered medications are versatile in that they can be Medications given orally are also subject to the first pass effect. When released slowly in the gastrointestinal tract, or all at once.(3) medications are absorbed through the gastrointestinal tract, they are There are several disadvantages of the oral route of drug transported through the portal vein to the liver where drug metabolism administration. The effects attained through the oral route are often occurs. Some medications are metabolized more than others during too slow for emergency situations, and this route cannot be used the first pass effect, potentially causing a significant decrease in drug when patients are unconscious or unable to swallow. Since orally bioavailability.(4) administered medications are absorbed in the stomach and small Administration alert! Medications that experience significant first pass intestine, this route cannot be used in patients without a functioning effects include morphine, lidocaine, diazepam, and propranolol. gastrointestinal tract or those on NPO orders, and oral administration
Dissolution rates and gastric emptying There are many factors that affect absorption of medications that have There can be significant variations in gastric emptying speed from been administered orally. The physical state of the drug can have a patient to patient, since there are many external factors that can have significant impact on the dissolution rate, or the process by which a an impact on this time frame. For example, the stomach naturally has a drug particle is dissolved. Medications given orally in solid dosage more rapid gastric emptying time when empty than immediately after a forms must be dissolved by gastrointestinal fluids before the drug meal. Therefore, medications administered on an empty stomach may particles become available for absorption. Medications that rely on an remain in the stomach for a shorter period of time than medications acidic fluid for dissolution are processed in the stomach, while those administered during or after a meal, affecting the drug’s dissolution medications that require a basic solution for dissolution are processed and absorption. in the intestines. Concurrent medications can also impact gastric emptying time. Oral medications administered in liquid solutions or rapidly Drugs with anticholinergic properties, including amitriptyline and dissolving dosage forms are more readily available for absorption, diphenhydramine, can slow gastric emptying times, resulting in and absorption is limited only by the rate at which the medication can increased absorption of medications absorbed from the stomach. cross membranes at the absorption site. These dosage forms are more Medications that increase gastric mobility, including laxatives, can appropriate for situations where an effect is desired relatively quickly move medications past their preferred site of absorption too quickly, and simple administration is desired. resulting in reduced drug absorption. Some dosage forms are created to allow for slow dissolution, including Administration alert! When digoxin, a medication with a slow extended release preparations. Certain medications are also known for absorption rate, is administered concurrently with milk of magnesia, their slow solubility, including digoxin. Slow release preparations are the absorption of digoxin is significantly reduced due to increased administered with the consideration that they may not be completely gastrointestinal mobility. absorbed due to the natural tendency of the gastrointestinal tract to The patient’s condition can also affect gastric mobility. Elderly move substances along, and the effects of disease states that alter patients have slower gastrointestinal mobility, as well as diabetic gastric emptying or gastrointestinal mobility must be taken into patients. Other factors that can affect medication absorption from the consideration as well. gastrointestinal tract include the surface area available for medication Gastric emptying time can have a significant impact on the absorption absorption, blood flow at the potential absorption site, the water of orally administered medications. The average gastric emptying solubility of the medication being administered, and the concentration time, or the time a medication is expected to remain in the stomach, is of medication at the absorption site.(5) between two to four hours. The small intestine has a longer emptying time, which can range from 4 to 10 hours on average.
Pharmacy.EliteCME.com Page 37 Sublingual route of administration The sublingual route is preferred for certain medications that must Sublingual administration is also beneficial for medications that are be absorbed rapidly for quick onset. Sublingual tablets are easily sensitive to the acidic environment in the stomach. Bypassing the dissolved and are taken by placing the tablet under the tongue where stomach via sublingual administration prevents the medication from it disintegrates for absorption. The drug is absorbed into the venous being inactivated prematurely by the low pH in the stomach. system under the tongue, which transports the medication to the Disadvantages of the sublingual route include the requirement to superior vena cava. Transit through this method protects sublingual keep the medication in the mouth until it dissolves, often imparting medications from first pass metabolism in the liver, allowing the an unpleasant taste in the process. Sublingual tablets are also fragile medication to arrive at its site of action before it is metabolized. and sensitive to moisture, often requiring specialized packaging and Administration alert! Nitroglycerin, commonly administered storage. Additionally, sublingual tablets must be designed to be small in sublingual form, would never reach systemic circulation if and easy to disintegrate, often resulting in higher costs than their oral administered orally and swallowed, as it would be inactivated by counterparts.(3) hepatic metabolism.(4)
Buccal route of administration Similar to the sublingual route, the buccal route involves disintegrating Disadvantages of the buccal route are similar to the sublingual route, the medication in the oral cavity. In this route, the medication is and include the experience of an unpleasant taste due to keeping the dissolved on the inside of the cheek, between the cheek and the gums. medication in the mouth for a longer period of time. Buccal tablets are The absorbed medication then travels to the bloodstream, bypassing often more expensive than more conventional dosage forms, and are the acidic gastric environment and hepatic metabolism. less widely available oral or injectable dosage forms.(3) Administration alert! Fentanyl buccal tablets have been developed to bypass the first pass metabolism that can significantly reduce the effectiveness of fentanyl.(6)
Rectal route of administration The rectal route of administration is another route that uses the an oral medication from getting to its site of absorption in a timely gastrointestinal tract for absorption, though in a less conventional way. manner. Patients with restrictions on oral consumption of food or Medications administered rectally are commonly found in suppository water and patients who recently underwent surgery are also candidates form, which contains the drug mixed in a substance that melts at for rectal medication administration.(3) body temperature. When inserted into the rectum, the suppository Rectally administered medications partially bypass the liver, with melts, releasing the medication to be absorbed through the rectal wall. about 50 percent of the drug bypassing hepatic metabolism, reducing Enemas can also be used to apply liquid medication to the rectal tissue. the effects of first pass metabolism. Disadvantages of the rectal route The rectal wall is thin and has a rich blood supply, allowing rectally include irritation of the rectal mucosa, awkward administration, and administered medications to be absorbed readily. potentially variable absorption, depending on the condition of the The rectal route is particularly beneficial for patients who are rectum.(4) unconscious or are experiencing nausea or vomiting that will prevent
Parenteral routes of administration: Intravenous Administering medications through the intravenous route ensures that Drug solutions that are irritating can be administered intravenously if the drug gets into the bloodstream as quickly as possible. Absorption is injected slowly, because the circulating blood quickly and effectively bypassed when a drug is injected directly into a vein, resulting in rapid dilutes the solution, reducing irritation. An example of this can be and complete bioavailability. Drug delivery can be controlled more seen with vancomycin, a caustic drug. When administered rapidly, precisely and adjusted based on the patient’s response, in a manner vancomycin cause phlebitis, or irritation of the veins, in addition to that is not possible with other forms of medication administration. other reactions. It is therefore indicated to administer vancomycin over However, direct access to the bloodstream requires sterile procedures the course of at least 60 minutes to minimize pain, venous irritation, to prevent infections and embolisms. and infusion reactions. Intravenous administration allows medications to be administered Unlike many enteral routes, the intravenous route can be used rapidly, achieving high drug concentrations. Bolus injections can in unconscious patients, allowing these patients to receive the be given to administer a high dose of a medication rapidly, and are medications they need rapidly. Disadvantages of the intravenous particularly beneficial in emergency situations. route include greater potential for adverse effects of medications, Administration alert! Tissue plasminogen activators (tPA), used to since high concentrations are achieved rapidly. There is also the risk break down blood clots in emergency situations, can be administered of embolism when air is injected into the vein with the drug, which by an intravenous bolus to ensure the medication gets to the site can be potentially fatal. Pain at the injection site is also considered a of action quickly and efficiently, increasing the chance of positive disadvantage.(3) outcomes for the patient.(4)
Administering an intravenous medication The first step in administering an intravenous medication is to access central vein, starting at the subclavian or jugular vein and ending at a the vascular system. This can be done using either a needle or a point of the vascular system with high blood flow. Central access often catheter. Needles are used for short-term vascular access. Patients allows for a longer distance between the entry point of the catheter and needing long-term intravenous access can have catheters placed its endpoint, reducing the risk of infection as compared to peripheral peripherally, such as in the arm, or ports surgically placed into a more
Page 38 Pharmacy.EliteCME.com catheters. Central catheters are often more durable than peripheral Intravenous infusions can be administered in a similar manner, but catheters.(3) instead of pushing the medication through a syringe into the IV Before administering an intravenous bolus or pushed medication to a access port, the medication is contained in an intravenous bag that patient, the nurse should ensure the medication is administered to the is connected to the port through tubing. Infusion pumps or regulator correct patient by verifying two patient identifiers. Then the correct clamps can be used to control the flow rate of the medication medication must be selected and prepared in an appropriate dosage into the patient, and should be used according to manufacturer calculated for the patient. Next, the patient’s intravenous access point recommendations, pharmacy instruction, and facility guidelines. should be located and cleaned with an alcohol swab. Once cleaned, the Guidelines for administering IV medications can vary based on the syringe can be connected to the intravenous access line and should be practice location; facility guidelines should always be followed to drawn back gently to pull a small amount of blood into the syringe; ensure proper delivery of these products. Intravenous medications this is to ensure the medication is being delivered into a vein. Then administered in the same line as other medications should be verified the medication can be administered by depressing the plunger of the for compatibility before administration by checking the facility’s syringe at a rate determined by the facility policies, pharmacy staff, or guidelines or various references, including Trissel’s Stability of medication manufacturer. Compounded Formulations.(5)
Subcutaneous route of administration Subcutaneous administration is used for various types of medications can also be pumped into the subcutaneous layer slowly through and vaccinations, and involves injecting the product into the catheters, as in the case of insulin pumps.(4) subcutaneous layer under the skin, directly below the dermis and Medications administered subcutaneously must not be irritating to above the muscular layer. After injection into the subcutaneous layer, the tissue. Irritants injected subcutaneously can cause pain, tissue the drug can cross into the bloodstream. Absorption rates following a sloughing, and necrosis.(4) Short needles should be chosen for subcutaneous injection are slow, allowing for a prolonged effect of the subcutaneous injections, such as a 5/8- to ½-inch needle length, to medication. ensure drug delivery to the proper layer. No more than two milliliters Drugs that are designed for subcutaneous injection can be developed of solution should be injected into the subcutaneous tissue at any one in ways that can alter the absorption time through modifications to the time, and the needle can be inserted into the skin at a 45-degree (if medication’s pH or particle size. Medications can also be developed as using a longer needle) or 90-degree angle (if using a shorter needle) implantable pellets that release medication into the subcutaneous layer after pinching the skin. Injection sites should be rotated to prevent slowly over weeks or months, such as contraceptives. Drug products lipohypertrophy and lipoatrophy.(3)
Intramuscular route of administration Medications administered intramuscularly are injected into the muscle Intramuscular injections require a longer needle length to ensure and absorbed into the bloodstream. Rapid absorption occurs if the delivery to the proper tissue, and 1- to 1½-inch needles are commonly drug product is contained in an aqueous solution, with some variation used. After cleaning the skin with an alcohol swab, the needle should based on the blood flow and fatty content of the injection site.Aqueous be inserted into the muscle at a 90-degree angle, and the solution solutions injected into the deltoid muscle are absorbed faster than should be injected at a rate of approximately 1 mL every 10 seconds. solutions injected into the gluteus maximus, particularly in females. The most common adverse reaction to intramuscular injections is Absorption is slower with depot or oil based forms, allowing for a slow, injection site pain. constant release of medication. Heat, massage, and exercise can also have an effect on drug absorption through the intramuscular route.(3)(4)
Intradermal route of administration Intradermal injections deliver medications into the dermis, the layer discomfort for the patient, intradermal injections are limited to less of the skin directly under the epidermis. To administer an intradermal than 0.5 mL per injection.(3) injection, the skin is cleansed with an alcohol swab, then the needle is Administration alert! Diagnostic skin testing and certain vaccinations inserted into the skin at a 10- to 15-degree angle, to prevent injection are administered intradermally. into incorrect layers of the skin. Since large fluid volumes create
Intrathecal route of administration When rapid effects are needed in the meninges or cerebrospinal administering intrathecal therapies, the medication preparation cannot areas, injections into the spinal subarachnoid space may be necessary. contain preservatives and must be sterile to ensure infectious agents This route of administration bypasses the blood–brain barrier to are not introduced into the cerebrospinal area.(5) ensure delivery of medication to the central nervous system. When
Pulmonary route of administration The pulmonary route of administration can be used for various types of for rapid absorption into the bloodstream. First pass metabolism is inhaled medications and gasses, both to directly treat the lungs as well avoided in this route of administration.(5) as for absorption into the bloodstream. Medications are inhaled with Most medications inhaled into the pulmonary system are designed for the breath and are either applied to or absorbed through the pulmonary topical application to the lungs rather than systemic absorption. There epithelium and respiratory mucous membranes. Since the alveoli of are several methods used to apply medication to the lungs, including the lungs create a large surface area, absorption can be rapid, but the metered dose aerosol inhalers, dry powder inhalers, and nebulized complicated path from the mouth to the alveoli presents a physical solutions. These methods involve breathing the medication with the barrier, preventing large drug particles from reaching the alveoli for breath into the lungs to deliver drug particles to the bronchioles.(1) absorption. Gaseous anesthetics are vapors that can reach the alveoli
Pharmacy.EliteCME.com Page 39 Intranasal route of administration The intranasal route is used to apply medications to the nasal cavity on the type of device. If necessary, dosing can be repeated in the for local treatment. They can be delivered through metered dose nasal other nostril. After application, a gentle sniff can help to move the actuators, nasal aerosols, and nasal inhalers. medication higher into the nasal cavity. The tip of the device should be Before administering an intranasal spray, the nose should be gently rinsed with hot water before replacing the cap.(1) blown first to clear the nostrils, then the hands should be washed.Then Administration alert! Antihistamines, corticosteroids, and the patient’s head should be held upright, and the tip of the applicator decongestants are commonly used to treat conditions involving the inserted into one nostril. The medication can then be released into the nasal mucosa. nasal cavity by pressing the actuator or squeezing the bottle, depending
Ocular route of administration Ophthalmic medications can be applied topically for local effects carefully, while ensuring the applicator does not touch the eye at any in the eye. Many of these medications must be absorbed through point. Ointments can be applied by pulling the lower eyelid down to the cornea for effectiveness; infections or trauma to the cornea can form a small sac, then drawing the ointment in a small ribbon into increase the rate of absorption. Suspensions and ointments, as well as the sac. The eyes should not be rubbed after application. If more than ocular inserts, can delay the absorption of the medication to increase one agent is being used in the eye, wait 5 minutes after instilling eye the duration of its action.(4) drops, and 10 to 15 minutes after using ointments before administering Prior to administering ophthalmic medications, the hands should be another product. After applying the medication to the eye, the cap washed to prevent the spread of infection or the introduction of foreign should be replaced quickly and carefully, while avoiding touching the substances into the eye. Drops should be applied to the conjunctiva tip of the applicator.(1)
Otic route of administration When local action of a medication is desired in the outer ear, drugs When ready to administer, the patient’s affected ear should be tilted so may be administered through the otic route. Liquid formulations of the ear canal is perpendicular to the ground. Then the ear canal must antibiotics, earwax removers, and numbing agents are commonly be straightened; for children younger than 3 years of age, the ear lobe indicated for use in the ear. If a desired medication is not available should be pulled down and back, for anyone older than 3 years of age, in an otic dosage form, ophthalmic products may be used, but otic the upper part of the ear should be pulled up and back. Liquid otic products should never be used in the eye due to the higher acidity of drops may then be administered into the straightened ear canal, and care otic formulations. should be used to ensure the dropper does not touch the ear to prevent Before administering otic medications, the hands should be washed contamination. If possible, the patient should keep their head with the thoroughly. The medication may be warmed to body temperature by ear canal perpendicular to the ground for five minutes; if not possible, a holding the bottle in the hands before application to reduce discomfort. cotton ball can be inserted gently into the outer part of the ear.(1)(7)
Vaginal route of administration The vaginal route is similar to other parenteral routes of administration include creams, ointments, foams, tablets, suppositories, solutions, and in that it bypasses the degradation of drug products by gastric acid intrauterine devices. Disadvantages of this route include the potential and first pass metabolism. However, absorption through this route can for toxic shock syndrome when vaginal dosage forms are used during be variable due to changes in fluid secretion level and pH relatively menstruation, and the possibility of some dosage forms being expelled quickly. This route is commonly used for the topical application of from the vagina after insertion.(1) medications to treat conditions of the vagina, with dosage forms that
Transdermal route of administration The transdermal route is used to allow medications to penetrate intact improved when the medication is suspended in oil and applied to the skin for absorption into the bloodstream. Transdermal medications skin. Absorption can also be improved by covering the skin with an are available as patches and tapes that can be stuck to the skin for occlusive dressing after medication is applied. absorption into the bloodstream. There are two types of transdermal The transdermal route is beneficial for patients who have trouble systems: those that contain methods to control the release of remembering to take medications, as well as unconscious patients. medication within the transdermal system, and those that allow the They are simple to use, as they only need to be stuck onto the skin in a skin to control the rate of absorption. designated area, dictated by the drug manufacturer. Disadvantages of The skin is penetrable by many types of drug products, but absorption transdermal systems include skin sensitivity at the application site as is dependent on the surface area of the skin where medication is well as issues with adhesion of the system to the skin for the required applied, as well as the lipid solubility of the drug. Highly lipid soluble period of application time.(4) medications are readily absorbed, so transdermal absorption can be
Dermal route of administration Topical agents are commonly used for their local effects on the the treatment of various skin conditions. These products are relatively skin. Creams, ointments, gels, solutions, powders, and aerosols are easy to apply, and can often be easily removed if necessary. commonly used to apply medication directly to the dermal layer for
Administering medications with parenteral nutrition Parenteral nutrition is often used in patients who do not have oral or enteral nutrition. Patients receiving parenteral nutrition are functioning gastrointestinal tracts, or in patient who cannot tolerate commonly receiving other IV medications as well. When attempting Page 40 Pharmacy.EliteCME.com to administer medications with parenteral nutrition, it is important Chemical and physical compatibility of the medication and parenteral to ensure these medications are compatible with parenteral nutrition nutrition should also be documented. solutions to ensure both drug and nutritional therapies are safe and Using parenteral nutrition as a vehicle for drug administration is effective. advantageous because it consolidates dosage administration, conserves Intravenous medications are often administered as a separate solution fluid volume in fluid-restricted patients, requires fewer venous piggybacked on the parenteral nutrition line, though some medications catheterizations, and decreases administration times. However, there can be added directly to the nutrition solution. There are several factors is a significant lack of safety and compatibility data for combining to consider when administering medications in this fashion, since intravenous medications with parenteral nutrition, limiting the there can be physiochemical incompatibilities between the drug and versatility of this practice.(7) nutritional solution. Before combining IV medications and parenteral Administration alert! Medications commonly added to parenteral nutrition, compatibility should be evaluated to ensure the combination nutrition include H2 antagonists and regular insulin. will be stable for 24 hours and able to endure continuous infusion.
Administering medications with enteral nutrition Enteral nutrition is often chosen to deliver nutritional solutions solution. The dosage form of the medication administered through a through tubing to the stomach or small intestine in patients who cannot feeding tube is particularly important. Liquid medications, including consume food orally but have a functional gastrointestinal tract. suspensions, solutions, and elixirs, are preferable as they are less likely There are several types of enteral feeding tubes that are classified by to clog the tubing. However, some liquid formulations have properties the placement of each end of the tubing, including nasogastric tubes, that can increase the potential for adverse effects, including containing nasojejunal tubes, and gastrostomy tubes. high concentrations of sorbitol or being hypertonic. Medications can also be administered through feeding tubes when Solid dosage forms can also be administered to a patient with a feeding patients cannot swallow. However, several factors must be taken into tube, but tablets must be crushed and capsules must be opened to consideration when medications are administered through this route to minimize the risk of clogging the feeding tube. The medication should prevent complications. Feeding tubes that deliver medications directly not be added to enteral feeding solutions; they should be administered to the stomach allow for medications to be broken down by stomach separately and the tubing should be flushed with approximately 30 mL acid, but tubing that bypasses the stomach does not allow medications of water before and after administration.(7) Some medications interact to dissolve in the same fashion. Medications that require action with enteral feeding solutions, such as warfarin, fluoroquinolones, in the stomach, such as antacids, would not be effective in tubing proton pump inhibitors, phenytoin and carbamazepine. Medications that delivers medication to the small intestines. The type of feeding that interact with enteral nutrition solutions may need to be schedule the patient is receiving can also affect absorption; continuous administered at a different time than nutritional solutions, or feeding into the stomach may need to be stopped to allow medications alternative therapies may need to be explored.(8) to be absorbed on an empty stomach, while dosing regimens can often Since certain medications cannot be crushed or opened, caution must be arranged around intermittent feeding schedules. be used to ensure the medication will be effective once manipulated. When administered incorrectly, medications can clog feeding tubes, A full list of medications that cannot be crushed is available from the increase adverse reactions, alter medication efficacy, or create Institute for Safe Medication Practices, at http://www.ismp.org/tools/ pharmacokinetic incompatibilities between the drug and nutritional donotcrush.pdf.(9)
Considerations for drug administration in pediatric patients Pediatric patients experience several unique considerations when it their young age, small body surface area, low weight, and incomplete comes to medication administration; these considerations are due to body development.
Oral administration Full-term infants have a gastric pH between 6 and 8 at birth, which Administration alert! Acid-labile medications, or those that are easily generally declines to between 1 and 3 within 24 hours of birth. destroyed by gastric acid, such as penicillin and ampicillin, result in Premature infants generally have an elevated gastric pH that can higher serum concentrations in premature infants. remain high for up to 4 months after birth due to undeveloped Gastric emptying is also slower in premature infants, resulting in gastric acid secretion systems. This can have a significant impact on increased contact times with the gastrointestinal mucosa. This can the absorption and metabolism of orally administered medications increase absorption of medications and have a significant impact on and must be taken into account when administering medications to their effect in premature infants.(7) premature newborns.
Intramuscular administration Intramuscular drug absorption can also be altered in premature infants. result in unpredictable drug absorption, so the intramuscular route is This population experiences lower muscle mass, more vasomotor avoided in neonates unless there is an emergency or intravenous sites instability, lower blood perfusion to various muscles, and inadequate cannot be used.(7) muscle contraction in comparison to full-term infants. These issues can Topical administration Topical drug absorption can also be altered in newborn infants. In infants, the ratio of body surface area to body weight is the highest At birth, infants have a poorly developed epidermal barrier and of any age group, resulting in higher systemic exposure to topical experience higher levels of skin hydration, which can lead to increased medications. This can be a disadvantage when it comes to medications drug absorption. such as corticosteroids and rubbing alcohol, increasing the risk of toxic
Pharmacy.EliteCME.com Page 41 effects associated with these products. However, this effect can be Administration alert! Theophylline, for example, can be applied as a used advantageously with other topical agents.(7) topical gel to premature infants less than 30 weeks gestation to achieve therapeutic serum concentrations for the treatment of apnea.(7)
Rectal administration Rectal administration can be used as an alternative route for to treat fevers in infants, and ensures the medication gets absorbed pediatric patients who are vomiting or otherwise unable to take oral effectively.(7) medications. Rectally administered acetaminophen is commonly used Otic administration Otic administration in children is different depending on the age and back in children younger than 3 years of age. Children older than of the child, since the anatomy of the ear is slightly different in age 3 years, should have the upper part of the ear pulled up and back younger children than older children. To straighten the ear canal for before medication administration.(1) administration of otic medications, the ear lobe should be pulled down
Altering dosage forms for pediatric patients Many medications used to treat pediatric patients are not available in solution to other solutions containing propylene glycol should be pediatric dosage forms. Adult drug products are often used in very avoided to prevent toxic side effects.(7) small amounts to allow for administration to pediatric patients. Care Orally administered medications that are only available in tablet form must be used when calculating these dosages and administering to may need to be altered for administration to pediatric patients. These young patients to ensure the proper dosage is administered, to prevent products can often be crushed and mixed into applesauce or pudding medication errors. to make the medication palatable for pediatric patients. However, Medications can be diluted into alternative solutions for administration not every type of tablet can be crushed. Extended-release tablets, to pediatric patients. When diluting medications for pediatric tablets with enteric coatings, and effervescent tablets are examples administration, appropriate vehicles must be selected to avoid of medications that cannot be crushed. A full list of medications that unnecessary adverse effects. For example, phenobarbital is available cannot be crushed is available from the Institute for Safe Medication in a solution that contains propylene glycol, a substance that can result Practices, as referenced in the section on altering dosage forms for in hyperosmolality if administered to infants. Adding phenobarbital patients using enteral nutrition.(9)
Medication adherence Medication adherence in pediatric patients can be more complex than Adherence can also be negatively affected by several other factors in in adults. A study of adolescent asthma patients sought to examine children and adolescents. These include:(7) the causes of near-fatal asthma attacks. Medication adherence was ●● Inadequate communication between the physician and the patient/ considered an issue in many of the studied adolescents, and was related caregiver. to the patient’s denial of having severe asthma. Approximately 80% ●● Poor understanding of the severity of the patient’s disease state. of patients in this study were found to be in denial of their condition, ●● Fear of adverse effects from treatment. resulting in significantly increased morbidity in these patients.(10) ●● Lack of interest in the healthcare of the child. ●● Inconvenient medication dosing schedules or dosage forms. ●● Poor palatability of oral medications.
Dosing requirements in pediatric patients Calculating the dosage of medication needed for pediatric patients of pediatric patients aged 2 to 19 years were found to be obese in can be challenging. Dosages should be carefully calculated based on 2011–2012, according to the U.S. Centers for Disease Control. weight or body surface area, as required by the chosen medication. (11) The use of ideal body weight to calculate medication dosages Calculated dosages should be assessed for accuracy and compared can produce significantly different dosages than using actual body to common adult dosages to assess the appropriateness of the chosen weight. Additional studies are needed to determine the effects of dosage.(7) childhood obesity on drug absorption, metabolism, and excretion; in Obesity in children presents another challenge to calculating the meantime, the pharmacist’s best judgment should be used when medication dosages in pediatric patients. Approximately 17 percent calculating dosages for obese children.(7)
Drug interactions Due to the vulnerable nature of pediatric patients, drug interaction interactions, and pay particular attention to adolescent patients, data in this age group is generally lacking, with data commonly who may use alcohol, illicit drugs, or prescription medications extrapolated from adult studies. Healthcare providers should use recreationally.(7) the available adult information to determine the potential for drug
Considerations for drug administration in geriatric patients Geriatric patients, or those older than age 65 years, experience consideration when assessing appropriate drug therapy for geriatric physiologic changes as they age that can affect their pharmacotherapy. patients. Many of these changes can significantly impact the pharmacokinetics of medications administered to elderly patients, and must be taken into
Page 42 Pharmacy.EliteCME.com Absorption Absorption of medications taken orally can be affected by age-related A decrease in gastrointestinal motility is also observed in geriatric changes to the gastrointestinal system. Aging can reduce gastric blood patients, which can actually increase drug absorption. First-pass flow and decrease gastric acid secretion. This combination can reduce metabolism can also be decreased in older patients, increasing the the absorption of pH-dependent medications administered orally, overall effect of medications undergoing this type of metabolism. especially when combined with the use of antacids or proton pump The net effects of these age-related gastrointestinal changes can be inhibitors. difficult to predict and vary significantly from patient to patient and based on the medication being used, requiring the provider to evaluate medication therapy carefully.(12)
Distribution Distribution of medications in the body is dependent on many factors, diazepam, a fat-soluble medication that accumulates in fatty tissue including protein binding, lipid or water solubility, and blood flow. and releases slowly, prolonging its effect in geriatric patients. These These factors can all be affected by age-related changes. Elderly changes to volume of distribution can also significantly impact the patients generally have lower albumin levels than younger patients. drug dosage used for loading doses.(7) (12) Geriatric patients also experience a larger volume of distribution Administration alert! Using highly protein bound medications, such as for lipophilic drugs due to increased body fat, but a smaller volume of phenytoin, in elderly patients can leave significant amounts of the drug distribution for water-soluble medications due to lower levels of water. unbound, increasing the risk of adverse effects in geriatric patients as This can affect the overall effect of these medications, as seen with compared to younger patients.
Metabolism Geriatric patients experience several physiologic changes can have Metabolic activity through the cytochrome P450 enzyme system is an impact on drug metabolism. The aging process can reduce hepatic reduced, which could be related to an age-related reduction in hepatic blood flow, reducing the rate at which medications are delivered to mass.(7) Although there is not a standard dosing formula to decipher the the liver from their absorption site. This can significantly reduce the dosages of hepatically-metabolized medications in geriatric patients, it is metabolism of medications that are heavily extracted in the liver.(7) generally recommended to start with low doses and titrate the dose until Administration alert! Lidocaine and morphine, two medications that the medication is efficacious or causes adverse effects.(12) are heavily metabolized in the liver, can cause more adverse effects in elderly patients than in younger patients.
Excretion Renal function tends to decline with age, due to several physiologic The age-related decline in kidney function is fairly predictable and changes in the kidneys. A decrease in blood flow to the kidney can can be estimated in order to assess proper dosages of renally excreted be seen in elderly patients. The number and size of nephrons also medications. The Cockcroft-Gault formula is commonly used to assess decreases, which can lead to a decrease in kidney mass. renal function in adults whose weight is within 30% of their ideal body Since many medications are excreted renally, the age-related decrease weight. The Cockcroft-Gault formula is as follows: in renal function can impact the elimination of medications. As renal (140 – age in years) x weight in kilograms function decreases, the half-life of renally excreted medications such Creatinine Clearance = ------(× 0.85 if female) as gentamycin increases, potentially resulting in significant adverse Serum Creatinine (mg/dL) × 72 effects. Other medications, including meperidine, have metabolites While the Cockcroft-Gault formula is the most widely used formula created through hepatic metabolism that are excreted renally; to estimate creatinine clearance, other ways of assessing creatinine accumulation of these metabolites can create adverse reactions if clearance such as the Modification of Diet in Renal Disease (MDRD) their excretion is impaired. This can necessitate dosage changes of formula or an actual 24-hour urine creatinine collection may be more medications taken by patients with decreased renal function.(12) accurate. Since many drug manufacturers provide dosing information based on estimated creatinine clearance calculated with the Cockcroft- Gault formula, this formula remains commonly used.(7)(12)
References 1. The American Pharmacist’s Association. The Pharmacy Technician, 4th Edition. Englewood, CO: 7. Dipiro JT et al. Pharmacotherapy: A Pathophysiologic Approach. 8th ed. New York, NY: McGraw- Morton Publishing Company. 2010. Hill; 2011. 2. Schlesselman, LS. 10 Strategies to Reduce Medication Errors. 2008. Accessed November 30, 2014 8. Williams N. Medication Administration Through Enteral Feeding Tubes. Am J Health Syst at https://secure.pharmacytimes.com/lessons/200809-01.asp. Pharm. 2008;65(24):2347-2357. Accessed November 30, 2014 at http://www.medscape.com/ 3. Stein S. Boh’s Pharmacy Practice Manual: A Guide to the Clinical Experience. Accessed November viewarticle/585397. 24, 2014 at https://www.inkling.com/read/bohs-pharmacy-practice-manual-stein-3rd/chapter-8/ 9. Institute for Safe Medication Practices. Oral Dosage Forms That Should Not Be Crushed. January routes-of-administration. 2014. Accessed November 30, 2014 at http://www.ismp.org/tools/donotcrush.pdf. 4. Shri Shankaracharya Institute of Pharmaceutical Science. Routes of Drug Administration. 10. Campbell DA et al. Psychiatric and Medical Causes of Near Fatal Asthma. Thorax: 1995; 254-259. International Journal of Pharmaceutical Studies and Research. 2010. Accessed November 24, 2014 Accessed November 30, 2014 at http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1021188/pdf/ at http://www.technicaljournalsonline.com/ijpsr/VOL%20I/IJPSR%20VOL%20I%20ISSUE%20 thorax00308-0048.pdf. I%20JULY%20SEPTEMBER%202010/IJPSR%20VOL%20I%20ISSUE%20I%20Article%208.pdf. 11. Centers for Disease Control. Childhood Obesity Facts. September 2014. Accessed November 30, 5. Allen L, Popovich N, Ansel H. Ansel’s Pharmaceutical Dosage Forms and Drug Delivery Systems. 2014 at http://www.cdc.gov/obesity/data/childhood.html. Philadelphia: Lippincott Williams & Wilkins. 2011. 12. Wooten J. Pharmacotherapy Considerations in Elderly Adults. South Med J. 2012;105(8):437-445. 6. Mystakidou K et al. Oral Transmucosal Fentanyl Citrate: Overview of Pharmacological and Clinical Accessed December 1, 2014 at http://www.medscape.com/viewarticle/769412_2. Characteristics. Drug Delivery. 2006:13(4):269-276. Accessed November 30, 2014 at http:// informahealthcare.com/doi/abs/10.1080/10717540500394661%20.
Pharmacy.EliteCME.com Page 43 DRUG ADMINISTRATION Final Examination Questions Select the best answer for questions 1 through 10 and mark your answers online at Pharmacy.EliteCME.com. 1. Which of the following is NOT one of the eight rights of 7. When administering an intramuscular injection, the needle should medication administration? be inserted into the muscle at a ______angle. a. Right drug. a. 45-degree. b. Right dose. b. 90-degree. c. Right nurse. c. 10-degree. d. Right documentation. d. 15-degree.
2. Medications that are administered through the enteral route are 8. Intradermal injections are limited to less than ______per injection. absorbed in the ______. a. 0.1 mL. a. Digestive tract. b. 0.5 mL. b. Bloodstream. c. 1 mL. c. Liver. d. 2 mL. d. Skin. 9. If a patient is using an eye drop and an eye ointment, how long 3. Which of the following factors does NOT affect medication should the patient wait after instilling the eye ointment before absorption from the gastrointestinal tract? using the eye drop? a. The color of the medication administered. a. 5 minutes. b. The surface area available for medication absorption. b. 2 minutes. c. Blood flow at the potential absorption site. c. 30 minutes. d. The water solubility of the medication being administered. d. 10 to 15 minutes.
4. The ______is particularly beneficial for patients that 10. The aging process can reduce hepatic blood flow, ______are unconscious or are experiencing nausea or vomiting. the rate at which medications are delivered to the liver from their a. Oral route. absorption site. b. Sublingual route. a. Reducing. c. Buccal route. b. Increasing. d. Rectal route. c. Not affecting. d. Improving. 5. Administering medications through the ______ensures that the drug gets into the bloodstream as quickly as possible. a. Oral route. b. Intravenous route. c. Intramuscular route. d. Rectal route.
6. Short needles should be chosen for subcutaneous injections, including a ______needle length, to ensure drug delivery to the proper layer. a. 5/8-inch. b. 1-inch. c. 1½-inch. d. 2-inch.
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