Motofen Side Effects Center

Last updated on RxList: 5/16/2022
Motofen Side Effects Center

What Is Motofen?

Motofen (difenoxin hydrochloride and atropine sulfate) is an anticholinergic used to treat diarrhea.

What Are Side Effects of Motofen?

Common side effects of Motofen include:

Tell your doctor if you have unlikely but serious side effects of Motofen including:

  • stomach or abdominal pain or swelling,
  • severe nausea,
  • vomiting,
  • mental/mood changes (e.g., confusion, depression),
  • restlessness, or
  • numbness or tingling of arms or legs.

Dosage for Motofen

The recommended starting dose of Motofen in adults is 2 tablets (2 mg), then 1 tablet (1 mg) after each loose stool or 1 tablet (1 mg) every 3 to 4 hours as needed, but the total dosage during any 24-hour treatment period should not exceed 8 tablets (8 mg).

What Drugs, Substances, or Supplements Interact with Motofen?

Motofen may interact with ambenonium, pramlintide, MAO inhibitors, naltrexone, potassium supplements, or drugs that cause drowsiness such as antihistamines, anti-seizure drugs, barbiturates, medicine for sleep or anxiety, muscle relaxants, narcotics, or psychiatric medicines. Tell your doctor all medications and supplements you use.

Motofen During Pregnancy or Breastfeeding

During pregnancy, Motofen should be used only if prescribed. This drug passes into breast milk. Consult your doctor before breastfeeding. Withdrawal symptoms may occur if you suddenly stop taking this medication.

Additional Information

Our Motofen (difenoxin hydrochloride and atropine sulfate) Side Effects Drug Center provides a comprehensive view of available drug information on the potential side effects when taking this medication.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.


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Motofen Professional Information


In view of the small amount of atropine present (0.025 mg/tablet), such effects such as dryness of the skin and mucous membranes, flushing, hyperthermia, tachycardia and urinary retention are very unlikely to occur, except perhaps in children. Many of the adverse effects reported during clinical investigation of MOTOFEN® are difficult to distinguish from symptoms associated with the diarrheal syndrome. However, the following events were reported at the stated frequencies:

Gastrointestinal: Nausea, 1 in 15 patients; vomiting, 1 in 30 patients; dry mouth, 1 in 30 patients; epigastric distress, 1 in 100 patients; and constipation, 1 in 300 patients.

Central Nervous System: Dizziness and light-headedness, 1 in 20 patients; drowsiness, 1 in 25 patients; and headache, 1 in 40 patients; tiredness, nervousness, insomnia and confusion ranged from 1 in 200 to 1 in 600 patients.

Other less frequent reactions: Burning eyes and blurred vision occurred in a few cases.

The following adverse reactions have been reported in patients receiving chemically-related drugs: numbness of extremities, euphoria, depression, sedation, anaphylaxis, angioneurotic edema, urticaria, swelling of the gums, pruritus, toxic megacolon, paralytic ileus, pancreatitis, and anorexia.



Since the chemical structure of difenoxin hydrochloride is similar to meperidine hydrochloride, the concurrent use of MOTOFEN® with monoamine oxidase inhibitors may, in theory, precipitate a hypertensive crisis.

MOTOFEN® may potentiate the action of barbiturates, tranquilizers, narcotics, and alcohol. When these medications are used concomitantly with MOTOFEN®, the patient should be closely monitored.

Diphenoxylate hydrochloride, from which the principal active metabolite difenoxin is derived, was found to inhibit the hepatic microsomal enzyme system at a dose of 2 mg/kg/day in studies conducted with male rats. Therefore, difenoxin 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.

Drug Abuse And Dependence

MOTOFEN® tablets are a Schedule IV controlled substance.

Addiction to (dependence on) difenoxin hydrochloride is theoretically possible at high dosage. Therefore, the recommended dosage should not be exceeded. Because of the structural and pharmacological similarities of difenoxin hydrochloride to drugs with a definite addiction potential, MOTOFEN® should be administered with considerable caution to patients who are receiving addicting drugs, to individuals known to be addiction prone, or to those in whom histories suggest may increase dosage on their own initiative.

Diagnosis And Treatment

In the event of overdosage (initial signs may include dryness of the skin and mucous membranes, flushing, hyperthermia and tachycardia followed by lethargy or coma, hypotonic reflexes, nystagmus, pinpoint pupils and respiratory depression) gastric lavage, establishment of a patent airway and possibly mechanically assisted respiration are advised.

The narcotic antagonist naloxone may be used in the treatment of respiratory depression caused by narcotic analgesics of pharmacologically related compounds such as MOTOFEN® tablets. When naloxone is administered intravenously, the onset of action is generally apparent within two minutes. Naloxone may be administered subcutaneously or intramuscularly providing a slightly less rapid onset of action but a more prolonged effect.

To counteract respiratory depression caused by MOTOFEN® overdosage, the following dosage schedule for naloxone should be followed:

Adult Dosage: The usual initial adult dose of naloxone is 0.4 mg (one mL) administered intravenously. If respiratory function does not adequately improve after the initial dose, the same IV dose may be repeated at two-to-three minute intervals.

Children: The usual adult dose of naloxone for children is 0.01 mg/kg of body weight administered intravenously and repeated at two-to-three minute intervals if necessary.

Since the duration of action of difenoxin hydrochloride is longer than that of naloxone, improvement of respiration following administration may be followed by recurrent respiratory depression. Consequently, continuous observation is necessary until the effect of difenoxin hydrochloride on respiration (which effect may persist for many hours) has passed. Supplemental intramuscular doses of naloxone may be utilized to produce a longer lasting effect. TREAT ALL POSSIBLE MOTOFEN® OVERDOSAGES AS SERIOUS AND MAINTAIN MEDICAL OBSERVATION FOR AT LEAST 48 HOURS, PREFERABLY UNDER CONTINUOUS HOSPITAL CARE.

Although signs of overdosage and respiratory depression may not be evident soon after ingestion of difenoxin hydrochloride, respiratory depression may occur from 12 to 30 hours later.

Read the entire FDA prescribing information for Motofen (Difenoxin and Atropine)


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© Motofen Patient Information is supplied by Cerner Multum, Inc. and Motofen Consumer information is supplied by First Databank, Inc., used under license and subject to their respective copyrights.

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