Lomotil Side Effects

Generic name: atropine / diphenoxylate

Medically reviewed by Drugs.com. Last updated on Apr 17, 2025.

Note: This document provides detailed information about Lomotil.

Applies to atropine / diphenoxylate: oral solution, oral tablet Side Effects associated with atropine / diphenoxylate. Some dosage forms listed on this page may not apply specifically to the brand name Lomotil.

Applies to atropine / diphenoxylate: oral solution, oral tablet.

Precautions

It is very important that your doctor check your progress at regular visits to make sure that this medicine is working properly and to check for unwanted effects.

Diarrhea usually stops 2 days after treatment with this medicine. If your symptoms do not improve or if they get worse within 10 days of treatment, check with your doctor.

This medicine may cause serious stomach or bowel problems (eg, toxic megacolon). This is more likely if you also have ulcerative colitis. Check with your doctor right away if you have bloating, constipation, loss of appetite, nausea, vomiting, or stomach pain.

Check with your doctor if you have dizziness, fast, shallow breathing, a fast, weak heartbeat, headache, muscle cramps, pale, clammy skin, thirst, extremely high fever or body temperature, decrease in urine volume, decrease in frequency of urination, difficulty in passing urine, painful urination, dry skin and mouth. This may be signs of condition called atropinism.

Check with your doctor before using this medicine with alcohol or other medicines that affect the central nervous system (CNS). The use of alcohol or other medicines that affect the CNS with diphenoxylate and atropine combination may worsen the side effects of this medicine, such as dizziness, poor concentration, drowsiness, unusual dreams, and trouble with sleeping. Some examples of medicines that affect the CNS are antihistamines or medicine for allergies or colds, sedatives, tranquilizers, or sleeping medicines, medicine for depression, medicine for anxiety, prescription pain medicine or narcotics, medicine for attention deficit and hyperactivity disorder, medicine for seizures or barbiturates, muscle relaxants, or anesthetics, including some dental anesthetics.

If you think you or anyone else may have taken an overdose of this medicine, get emergency help at once. Taking an overdose of this medicine may lead to unconsciousness and possibly death. Signs or symptoms of overdose include severe drowsiness, shortness of breath or troubled breathing, fast heartbeat, and unusual warmth, dryness, and flushing of the skin.

This medicine may make you dizzy or drowsy. Do not drive or do anything else that could be dangerous until you know how this medicine affects you.

Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal or vitamin supplements.

Serious side effects of Lomotil

Along with its needed effects, atropine / diphenoxylate may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur while taking atropine / diphenoxylate:

Get emergency help immediately if any of the following symptoms of overdose occur while taking atropine / diphenoxylate:

Symptoms of overdose

• agitation
• back pain
• bigger, dilated, or enlarged pupils (black part of eye)
• blurred vision
• difficult or troubled breathing
• feeling of warmth
• fever
• garbled speech
• increased sensitivity of the eyes to light
• irregular, fast or slow, or shallow breathing
• loss of consciousness
• mood or mental changes
• pale or blue lips, fingernails, or skin
• seizures
• speech that is not understood
• stiff neck
• unusual tiredness or weakness

For healthcare professionals

Applies to atropine / diphenoxylate: oral liquid, oral tablet.

Nervous system adverse events

• Frequency not reported: Numbness of extremities, sedation/drowsiness, dizziness, headache, somnolence^[Ref]

Gastrointestinal

• Frequency not reported: Swelling of the gums, toxic megacolon, paralytic ileus, pancreatitis, vomiting, nausea, abdominal discomfort, constipation^[Ref]

Cardiovascular

• Frequency not reported: Tachycardia, cardiac irregularities (e.g. arrhythmias, bradycardia, palpitations)^[Ref]

Ocular

• Frequency not reported: Increased intraocular pressure, dilation of pupils with loss of accommodation, photophobia, angle closure glaucoma^[Ref]

Genitourinary

• Frequency not reported: Urinary retention, difficulty in micturition^[Ref]

Psychiatric

• Frequency not reported: Euphoria, depression, confusion, restlessness, hallucinations^[Ref]

Dermatologic

• Frequency not reported: Urticaria, pruritus, flushing^[Ref]

Hypersensitivity

• Frequency not reported: Anaphylaxis, angioneurotic edema^[Ref]

Metabolic

• Frequency not reported: Anorexia^[Ref]

Respiratory

• Frequency not reported: Respiratory depression in children^[Ref]

Other

• Frequency not reported: Malaise/lethargy, hyperthermia, dryness of the skin and mucous membranes^[Ref]

See also:

Frequently asked questions

• How to stop diarrhea - any medicine or remedy suggestions?

Further information

Lomotil side effects can vary depending on the individual. Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Note: Medication side effects may be underreported. If you are experiencing side effects that are not listed, submit a report to the FDA by following this guide.

Medical Disclaimer