Opiate Antidiarrheals – Paregoric, Diphenoxylate HCl/Atropine Sulfate, Loperamide HCl Other names for these drugs include Paregoric (camphorated tincture of opium), Opium Tincture, Logen®, Lomotil®, Lonox®, Lomanate®, Pepto Diarrhea Control®, Kaopectate II Caplets®, Imodium A-D caplets®, Neo-Diaral®, Diar-aid Caplets®, K-Pek II.
How Is This Medication Useful?
Among their other actions, opiates inhibit movement of the gastrointestinal tract, calm excessive GI propulsion associated with diarrhea. They also decrease secretion of fluids by the intestine, and may also enhance absorption of fluid by the intestines. These drugs are used mostly in dogs, and their use in cats is controversial. Many veterinarians do not recommend their use in cats. Generally, onset of action occurs within 45 minutes to one hour after dosing and is sustained for 3-4 hours. In dogs, loperamide (Imodium) reportedly has a faster onset of action and longer duration of action than diphenoxylate (Lomotil).
Are There Conditions or Times When Its Use Might Cause More Harm Than Good?
• All opiates should be used with caution in patients with low thyroid function (hypothyroidism), severe kidney disease, Addison's disease, and in geriatric or severely debilitated patients. • Opiate antidiarrheals should not be used in cases where the patient is allergic to narcotic pain killers analgesics, nor in patients taking monoamine oxidase inhibitors (selegiline, Anipryl, L- deprenyl, etc). • They should not be used in patients with diarrhea caused by a toxic ingestion or infection, until the toxin is eliminated from the GI tract (these drugs may cause toxins to be retained in the body longer). • Opiate antidiarrheals should be used with caution in patients with head injuries or other brain disorders associated with increased pressure in the brain or spinal fluid, and acute abdominal conditions (e.g., colic) as it may obscure the diagnosis or clinical course of these conditions. • It should be used with extreme caution in patients suffering from respiratory disease or from acute respiratory dysfunction (e.g., pulmonary edema secondary to smoke inhalation). • Opiate antidiarrheals should be used with extreme caution in patients with liver disease with symptoms of hepatic encephalopathy. Hepatic coma may result. • Many veterinarians recommend not using diphenoxylate or loperamide in dogs weighing less than 5 pounds, but this is probably a result of difficulty in dosing this small. Liquid forms may be used for small dogs safely. • Loperamide should be used with caution in herding breeds (e.g., Collies) who may be overly sensitive to it. • If your animal has any of the above conditions, talk to your veterinarian about the potential risks of using the medication versus the benefits that it might have.
What Side Effects Can Be Seen With Its Use?
• Animal studies have not yet demonstrated risk to the fetus during pregnancy by taking loperamide. • Animal studies have shown an adverse effect on the fetus by diphenoxylate/atropine, and its use is not recommended in pregnant dogs and cats. • It is not known whether loperamide is excreted in maternal milk. Safety during nursing has not been established. Exercise caution when administering diphenoxylate HCl with atropine to nursing patients. Diphenoxylic acid may be excreted in maternal milk and atropine is excreted in maternal milk, but effects on the infant may not be significant. • In dogs, constipation, bloat and sedation are the most likely adverse reactions encountered when usual doses are used. • Potentially, paralysis of the intestines, toxicity caused by paralysis of the colon, pancreatitis or neurologic problems could be seen. • Use of antidiarrheal opiates in cats is controversial; this species may react with excitatory behavior. • Overdosage of the opiate antidiarrheals could result in neurologic problems, cardiovascular, GI or respiratory problems. Because the opiates may significantly reduce GI movement, absorption from the GI may be delayed and prolonged. Naloxone may be necessary to reverse the opiate effects. Massive overdoses of diphenoxylate/atropine sulfate may also induce atropine toxicity (increased heart rate, dried secretions, red skin, etc)
How Should It Be Given?
• Other brain depressants (e.g., anesthetic agents, antihistamines, phenothiazines, barbiturates, tranquilizers, alcohol, etc.) may cause increased nervous system or respiratory depression when used with opiate antidiarrheal agents. • Opiate antidiarrheal agents should not be used in patients receiving monoamine oxidase (MAO) inhibitors (rarely used in veterinary medicine) for at least 14 days after receiving MAO inhibitors. These drugs include selegiline, Anipryl, and L-deprenyl. • The successful outcome of your animal’s treatment with this medication depends upon your commitment and ability to administer it exactly as the veterinarian has prescribed. Please do not skip doses or stop giving the medication. If you have difficulty giving doses consult your veterinarian or pharmacist who can offer administration techniques or change the dosage form to a type of medication that may be more acceptable to you and your animal. • If you miss a dose of this medication you should give it as soon as you remember it, but if it is within a few hours of the regularly scheduled dose, wait and give it at the regular time. Do not double a dose as this can be toxic to your pet. • Some other drugs can interact with this medication so tell your veterinarian about any drugs or foods that you currently give your animal. Do not give new foods or medications without first asking your veterinarian. • Dogs and cats take Paregoric two to three times daily, and should probably take it for no longer than 5 days at a time. • Dogs take Diphenoxylate/Atropine two to three times daily, and should probably take it for no longer than 5 days at a time. • Cats take loperamide two times daily.
What Other Information Is Important About This Medication?
• Paregorics should be stored in tight, light-resistant containers. Avoid exposure to excessive heat or direct exposure to sunlight. • Diphenoxylate/atropine tablets and oral solution should be stored at room temperature in well- closed, light-resistant containers. Liquids should not be frozen. • Loperamide capsules or oral solution should be stored at room temperature in well-closed containers. It is recommended that the oral solution not be diluted with other solvents.
References: Plumb's Veterinary Drug Handbook