Copyright EMAP Publishing 2020 This article is not for distribution except for journal club use Clinical Practice Keywords Medicines/Administration/ Administration route/Patient safety Review Medicines management In this article... ● Different routes used to administer medicines ● Benefits and limitations of the different administration routes ● Points to consider before administering medicines

Medicines administration 1: understanding routes of administration

Key points Authors Martin Shepherd is clinical director of pharmacy and therapy, Chesterfield Bioavailability is Royal Hospital NHS Foundation Trust. Updated in 2020 by Eileen Shepherd, clinical the proportion of editor, Nursing Times. a medicine that reaches the systemic Abstract Medicines administration is a core responsibility of registered nurses in circulation healthcare settings and is increasingly being undertaken by nursing associates. Before administering any medicine, the person carrying out the procedure must be familiar The chosen route with the advantages and limitations of the prescribed route and know the indications, of administration contraindications and side-effects of the medicine they intend to give. This article, the will influence a first in a two-part series, provides an update on the routes of administration. Part 2 will medicine’s outline the procedure for administering medicines to patients. effectiveness and the patient’s Citation Shepherd M, Shepherd E (2020) Medicines administration 1: understanding experience routes of administration. Nursing Times [online]; 116: 6, 42-44.

Care should be taken before edicine administration is a core terms tend to be used interchangeably. Ide- crushing medicines, responsibility of registered ally, any medicine should be effective, safe and advice should nurses in healthcare settings; and selective in its mode of action. always be sought increasingly, the task is also Effectiveness refers to how the body from the pharmacist M being carried out by nursing associates. To responds to a medicine; if a medicine fails or prescribing ensure patient safety, it is essential the cor- to lead to its intended result, there is no doctor rect procedure is implemented so the cor- benefit to prescribing it (Burcham and rect medicine is given in the prescribed Rosenthal, 2016). In the UK, the National Crushing modified- amount using the most appropriate route. Institute for Health and Care Excellence release tablets can Before administering any medicine, the carries out technology appraisals on the result in the full dose person carrying out the procedure must be use of new and existing medicines and of medicine being familiar with the advantages and limita- treatments in the NHS (Bit.ly/NICE released at once tions of the prescribed route, and know the TechAppraisal); these use clinical evidence rather than gradually indications, contraindications and side- on effectiveness and economic evidence on effects of the medicine they intend to give. whether the medicine/treatment repre- Administering sents value for money. medicines directly Medicine use and safety All medicines are evaluated to assess into the systemic A drug is defined as any chemical that can their safety, but no medicine is entirely circulation by affect living processes (Burchum and risk free. Nurses should: injection or infusion Rosenthal, 2016); this article focuses on l Be aware of any potential problems that means the medicine those that are administered for thera- patients may experience when taking is rapidly distributed peutic effect. To make it suitable for any medication; to its sites of action administration to a patient, a drug has to l Know how and when to report these. be formulated into a preparation that ena- In the UK, the Yellow Card scheme (Bit. bles it to be taken or given – such as a tablet ly/MHRAYellowCard) collects and moni- or injection. Once formulated, the drug tors information on suspected safety con- becomes a medicine; however, the two cerns or incidents involving medicines

Nursing Times [online] June 2020 / Vol 116 Issue 6 42 www.nursingtimes.net Copyright EMAP Publishing 2020 This article is not for distribution except for journal club use Clinical Practice Review and medical devices. The scheme is run by Box 1. Administration routes Non-oral routes the Medicines and Healthcare products While the oral route is most frequently Regulatory Authority and relies on health Enteral: oral, via enteral feeding tubes used for medicine administration, it is not professionals and patients voluntarily Topical: via skin, eyes, ears, nose, always appropriate. In such situations a reporting suspected adverse drug reac- vagina, rectum, lungs (inhaled) range of alternatives is available to treat tions; it aims to provide an early warning Parenteral: intravenous, intramuscular, the patient effectively. that the safety of a product may require subcutaneous further investigation. Sublingual administration Ideally, a medicine should be selective The sublingual mucosa offers a rich supply in its action on the body. However, most understood in terms of their implications of blood vessels through which medicines medicines have side-effects and it is for the effectiveness of the drug therapy can be absorbed. This is not a common important to inform patients about these and the patient’s experience. route of administration but it offers rapid risks – as an example, antihistamines can absorption into the systemic circulation. cause drowsiness. Sometimes a decision Oral route The most common medicine given via has to be made by the patient and pre- The oral route is the most frequently used sublingual administration is glyceryl trini- scriber as to whether symptom relief is route of medicines administration and is trate in the treatment of acute angina. balanced against potential side-effects; in the most convenient and cost-effective The pharmaceutical industry has formu- some situations, the side-effects may out- (Dougherty and Lister, 2015). lated ‘wafer-based’ versions of medicines, weigh the benefits of the medicine. Although solid-dose forms such as tab- which dissolve rapidly under the tongue. lets and capsules have a high degree of These are aimed at particular groups of Administration drug stability and provide accurate patients who have difficulty taking tablets, The way in which medicines are dosage, the oral route is problematic such as rizatriptan for people with migraines administered will, to some extent, because of the unpredictable nature of gas- that are sometimes accompanied by nausea influence their clinical benefit and trointestinal absorption. For example, as this may prevent them from taking oral whether patients experience any adverse food in the gastrointestinal tract may alter treatments. Wafers are also used to treat con- effects. For example, if intravenous (IV) the gut pH, gastric motility and emptying ditions in which adherence is an issue; for furosemide is administered too quickly, it time, as well as the rate and extent of drug example, olanzapine can be administered by can cause deafness, while oral penicillin V absorption. the sublingual route when used to treat will not be well absorbed if given with Patients’ tolerance of solid-dose forms schizophrenia (Montgomery et al, 2012). food) (bnf.org). Two main factors also varies, particularly in very young and determine whether a medicine will reach older patients, for whom liquids or solu- Rectal administration its intended site of action in the body: tions may be preferable. However, many The rectal route has considerable disadvan- l Its bioavailability; medicines are not stable in solution; in tages in terms of patient acceptability due l How it is given (route of such cases, an alternative should be con- to cultural issues and the potential for dis- administration). sidered. Key points are outlined in Box 2. comfort, leakage and unpredictable absorption; however, it does offer a number Bioavailability Modified-release preparations of benefits (Hua, 2019). Drug delivery can Bioavailability is the proportion of a medi- Modified-release formulations can delay, be localised into the large bowel – for cine that reaches the systemic circulation prolong or target drug delivery. The aim is example, the use of rectal steroids in the and is therefore available for distribution to maintain plasma drug concentrations form of enemas or suppositories in the to the intended site of action (Burchum and for extended periods above the minimum treatment of inflammatory bowel disease. Rosenthal, 2016). The route of administra- effective concentration. Their main advan- Antiemetics can be administered rectally tion and formulation – tablet, capsule, tage for patients is that doses usually only to treat nausea and vomiting, and paracet- liquid – can influence its bioavailability. need to be taken once or twice daily. amol can be given to treat patients with a Medicines given by IV injection are said pyrexia who are unable to swallow. to have 100% bioavailability. Some medi- Crushing tablets cines that are particularly well absorbed by The process of crushing tablets is usually Box 2. Key points on oral the gastrointestinal mucosa, for example outside of the product licence and nurses route for administration the antibiotic ciprofloxacin, may have bio- should seek advice from a pharmacist or availability close to that of an IV dose (bnf. the prescribing doctor if they are uncer- l The oral route is convenient and org). However, most medicines do not have tain about a tablet and whether it is suit- cost-effective this level of availability by the oral route so able for crushing or the process will affect l Some patients, particularly children the dose given orally is usually higher than its efficacy (Dougherty and Lister, 2015). and older people may have problems that given parenterally. For example, the Modified-release tablets must not be swallowing tablets and capsules beta-blocker propranolol, when given crushed or broken. Damage to the release- l Modified-release formulations can orally, is administered in doses of 40mg controlling mechanism can result in the delay, prolong or target drug delivery and above; the equivalent IV dose is 1mg. full dose of medicine being released at l Nurses should seek advice from a once rather than over a number of hours. pharmacist or the prescribing doctor Routes of administration The entire dose of the medicine may then before crushing any tablets There are various routes of administration be absorbed too quickly, leading to tox- l Modified-release tablets must not be (Box 1), each of which has advantages and icity, or not absorbed at all, leading to sub- crushed or broken disadvantages. These routes need to be optimal treatment.

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Topical administration Box 3. Parenteral hypoglycaemic episodes (Dougherty and The topical application of medicines has administration Lister, 2015). obvious advantages in the management of localised disease. The medicine is available Advantages Intramuscular and subcutaneous almost directly at the intended site of l Can be used for medicines that are In general, the IM and SC injection of med- action, and because the systemic circula- poorly absorbed, inactive or icines establishes a deposit or ‘depot’ that tion is not reached in great concentration, ineffective if given orally will be released gradually into the systemic the risk of systemic side-effects is reduced. l The intravenous route provides circulation. The medicine’s formulation Examples of topical medicines include: immediate onset of action will influence the period over which it is l Eye drops containing beta blockers to l The intramuscular and subcutaneous released. For example, the formulation of treat glaucoma; routes can be used to achieve slow antipsychotic agents, such as flupentixol l Topical steroids to manage dermatitis; or delayed onset of action in oil, allows them to be administered once l Inhaled bronchodilators to treat l Patient adherence problems can be a month or every three months. asthma; avoided l Pessaries containing clotrimazole to IV route treat vaginal candidiasis. Disadvantages The IV route carries the greatest risk of any Topical administration has also become l Staff need additional training and route of medicine administration. By a popular way of introducing medicines assessment administering directly into the systemic into the systemic circulation through the l Can be costly circulation, either by direct injection or skin. The development of transdermal l Can be painful infusion, the medicine is instantaneously patches that contain drugs began with the l Aseptic technique is required distributed to its sites of action. This route introduction of a hyoscine-based product l May require additional equipment, of administration can be complex and it is for the treatment of nausea in the early for example programmable infusion now an integral part of the nurse’s role. 1980s (Pastore et al, 2015). The market for devices Those administering IV medicines must such products has since grown to include a have appropriate training and be deemed wide range of therapy areas including competent to undertake the procedure smoking cessation (nicotine replacement), include phenytoin, warfarin and flucloxa- (Dougherty and Lister, 2015). chronic pain (fentanyl), Parkinson’s dis- cillin (Bit.ly/BAPENEnteralDrugAdmin). ease (rotigotine). Medicines that have to be specially pre- Conclusion The transdermal route is not without its pared as liquids to enable administration It is important that any nurse adminis- problems – for example, some prepara- via enteral tube incur significant addi- trating medicines or delegating this proce- tions can cause local skin reactions (Pas- tional costs, and consideration should be dure to another member of their team tore et al, 2015), and the adhesiveness of given to alternatives before these are understands the different routes of medi- some patches can be a limitation. How- requested. A pharmacist should, there- cines administration and their limitations. ever, many patients find it a welcome alter- fore, be involved in any decision to admin- This will enable them to assess the effec- native to taking tablets. ister medicines via this route. tiveness of the medicine being adminis- BAPEN (British Association for Paren- tered and to identify any potential prob- Administration via enteral teral and Enteral Nutrition) has produced lems the patient may be experiencing with feeding tubes information about administration of med- the treatment. Part 2 of this series outlines Medicines should only be administered via icines via enteral feeding tubes as well as the procedure for the safe administration fine-bore enteral feeding tubes after other useful information leaflets for patients of medicines. NT routes have been considered (Bit.ly/BAPE- (Bit.ly/BAPENEnteralDrugAdmin). NEnteralDrugAdmin). Most medicines are References Burchum JR, Rosenthal LD (2016) Lehne’s not licensed for enteral administration Parenteral route Phamacology for Nursing Care. Elsevier. and this route is complex from a medico- Parenteral administration refers to any Dougherty L, Lister S (2015) The Royal Marsden legal perspective. non-oral means of medicine administra- Manual of Clinical Nursing Procedures. Wiley- Blackwell. Interactions that may compromise the tion, but is generally interpreted as Hua S (2019) Physiological and pharmaceutical effectiveness of a medicine can occur relating to injecting directly into the body, considerations for rectal drug formulations. between the medicine and the enteral feed bypassing the skin and mucous mem- Frontiers in Pharmacology; 10: 1196. and clinically significant interactions branes. The common parenteral routes are Montgomery W et al (2012) Orally disintegrating olanzapine review: effectiveness, patient intramuscular (IM), subcutaneous (SC) preference, adherence, and other properties. Useful resources and IV. Box 3 outlines the advantages and Patient Preference and Adherence; 6: 109-125. disadvantages of parenteral routes. Pastore MN et al (2015) Transdermal patches: history, development and pharmacology. British l British National Formulary Parenteral administration requires an Journal of Pharmacology; 172: 9, 2179-2209. bnf.nice.org.uk appropriate injection technique. If per- l Royal Pharmaceutical Society, formed incorrectly – for example using the Royal College of Nursing (2019) wrong size needle or cannula – it can cause CLINICAL Medicines management Professional Guidance on the damage to nerves, muscle and vasculature SERIES Administration of Medicines in and may adversely affect drug absorption. Part 1: Understanding administration Healthcare Settings. RPS/RCN. For example, inadvertent administration routes June Bit.ly/RPSAdministration of subcutaneous insulin into muscle can Part 2: Administration procedure July result in rapid absorption and

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