At therapeutic doses, the following have been reported; they are listed in decreasing order of severity, but not of frequency:
Nervous system: numbness of extremities, euphoria, depression, malaise/lethargy, confusion, sedation/drowsiness, dizziness, restlessness, headache.
Allergic: anaphylaxis, angioneurotic edema, urticaria, swelling of the gums, pruritus.
Gastrointestinal system: toxic megacolon, paralytic ileus, pancreatitis, vomiting, nausea, anorexia, abdominal discomfort.

The following atropine sulfate effects are listed in decreasing order of severity, but not of frequency: hyperthermia, tachycardia, urinary retention, flushing, dryness of the skin and mucous membranes. These effects may occur, especially in children.

THIS MEDICATION SHOULD BE KEPT IN A CHILD-RESISTANT CONTAINER AND OUT OF THE REACH OF CHILDREN SINCE AN OVERDOSAGE MAY RESULT IN SEVERE RESPIRATORY DEPRESSION AND COMA, POSSIBLY LEADING TO PERMANENT BRAIN DAMAGE OR DEATH.

Drug Abuse and Dependence

Controlled substance: Lomotil (diphenoxylate and atropine) is classified as a Schedule V controlled substance by federal regulation. Diphenoxylate hydrochloride is chemically related to the narcotic analgesic meperidine.

Drug abuse and dependence: In doses used for the treatment of diarrhea, whether acute or chronic, diphenoxylate has not produced addiction. Diphenoxylate hydrochloride is devoid of morphine-like subjective effects at therapeutic doses. At high doses it exhibits codeine-like subjective effects. The dose which produces antidiarrheal action is widely separated from the dose which causes central nervous system effects. The insolubility of diphenoxylate hydrochloride in commonly available aqueous media precludes intravenous self-administration. A dose of 100 to 300 mg/day, which is equivalent to 40 to 120 tablets, administered to humans for 40 to 70 days, produced opiate withdrawal symptoms. Since addiction to diphenoxylate hydrochloride is possible at high doses, the recommended dosage should not be exceeded.

Read the Lomotil (diphenoxylate and atropine) Side Effects Center for a complete guide to possible side effects »

Known drug interactions include barbiturates, tranquilizers, and alcohol. Lomotil (diphenoxylate and atropine) may interact with MAO inhibitors (see WARNINGS).

In studies with male rats, diphenoxylate hydrochloride was found to inhibit the hepatic microsomal enzyme system at a dose of 2 mg/kg/day. Therefore, diphenoxylate has the potential to prolong the biological half-lives of drugs for which the rate of elimination is dependent on the microsomal drug metabolizing enzyme system.

Last reviewed on RxList: 10/4/2010
This monograph has been modified to include the generic and brand name in many instances.