Before taking any medication, whether over the counter or prescription, talk to your healthcare provider or pharmacist about dosage, other medicines you are taking, or any other questions you might have about the treatment. Otherwise, carefully follow the directions on the drug package or on your prescription label.
Over the Counter (OTC) Drugs
Bismuth (Pepto-Bismol, generics) – This preparation is sometimes recommended for traveler’s diarrhea and chronic microscopic colitis. It has many disadvantages. The dose is 30ml of the pink liquid every 30 minutes up to 8 times a day. It turns the stool black and may interfere with the absorption of other drugs such as diphenoxylate (See below) and tetracycline. Chronic, excessive use may cause neurological complications and the salicylate component of the drug may cause salicylate toxicity.
Codeine – Codeine 15 mg. combined with acetaminophen (Tylenol, generic) is available by prescription or over the counter (OTC) in some jurisdictions. If nothing else is handy when stricken with acute diarrhea, two such tablets may help control your acute diarrhea until a regular antidiarrheal drug can be obtained. Beware that overuse use of an OTC codeine combination could include toxic doses of acetaminophen.
Loperamide (Imodium) – The safest of the opioid drugs, loperamide is available OTC in 1 and 2mg doses. Depending on age, the recommended dose is 2 mg after each loose bowel movement to a maximum of 16 mg/day. It has an opioid’s ability to slow gut transit and improve absorption of water from the intestines. Some evidence suggests it also improves anal sphincter tone. Although it has the lowest addiction potential of all opioids, it may cause sedation, nausea, and cramps. It is the best emergency treatment for mild attacks of diarrhea, and when taken preventively it may even help you avoid urgent exits during meetings or other events.
Codeine phosphate (generic) – The usual therapeutic dose of Codeine is 30 to 60 mg up to every four hours as necessary to control diarrhea. For this, a prescription is required in most jurisdictions. Codeine is potentially addicting, and unsuitable for chronic diarrhea. It is sedating, and causes nausea, making it a second choice after loperamide.
Diphenoxylate (Lomotil) – Because it is an opiate with some addictive potential, diphenoxylate is available only by prescription. It is combined with atropine so that excessive use will cause dry mouth and other undesirable side effects. It is useful if other drugs fail.
Cholestyramine (Questran) – Cholestyramine is a powdered resin with a plastic taste that binds bile salts and has a water-holding effect. When other treatments fail, it may relieve some cases of diarrhea. Rarely, chronic diarrhea occurs after removal of the gall bladder or the lower small intestine (ileum), and cholestyramine has a beneficial effect. Usually prescribed for patients with high cholesterol blood levels, it is available in 4mg packets and is taken with water. Occasionally, a very small dose will improve diarrhea, but for most cases, loperamide is preferable. In addition to its bad taste, cholestyramine may interfere with the absorption of some drugs and vitamins, and may cause hypersensitivity reactions. It should only be used for special cases with a doctor’s advice.