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Atropine and diphenoxylate

Generic name: atropine and diphenoxylate [ A-troe-peen-and-DYE-fen-OX-i-late ]
Brand names: Lomotil, Lonox, Lomocot, Vi-Atro
Dosage forms: oral liquid (0.025 mg-2.5 mg/5 mL), oral tablet (0.025 mg-2.5 mg)
Drug class: Antidiarrheals

Medically reviewed by on Mar 4, 2024. Written by Cerner Multum.

What is atropine and diphenoxylate?

Atropine affects the body in many different ways, such as reducing spasms in the bladder, stomach, and intestines.

Diphenoxylate is an antidiarrheal medication.

Atropine and diphenoxylate is a combination medicine used to treat diarrhea in adults and children who are at least 13 years old.

Atropine and diphenoxylate may also be used for purposes not listed in this medication guide.

Atropine and diphenoxylate side effects

Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Some side effects may occur up to 30 hours after you take atropine and diphenoxylate.

This medicine may cause serious side effects. Stop using this medicine and call your doctor at once if you have:

Common side effects of atropine and diphenoxylate may include:

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.


Do not use this medicine if you have diarrhea that is caused by bacteria or by taking an antibiotic. You should not use atropine and diphenoxylate if you have a bile duct disorder causing jaundice (yellowing of your skin or eyes).

Keep this medicine where a child cannot reach it. An overdose can be fatal to a child.

Before taking this medicine

You should not use atropine and diphenoxylate if you are allergic to atropine or diphenoxylate, or if you have:

Atropine and diphenoxylate is not approved for use by anyone younger than 6 years old. This medicine has not been proven safe or effective in children younger than 13 years old.

Tell your doctor if you have ever had:

It is not known whether this medicine will harm an unborn baby. Tell your doctor if you are pregnant.

It may not be safe to breast-feed a baby while you are using this medicine. Ask your doctor about any risks.

How should I take atropine and diphenoxylate?

Follow all directions on your prescription label and read all medication guides or instruction sheets. Your doctor may occasionally change your dose. Use the medicine exactly as directed.

Measure liquid medicine carefully. Use the dosing syringe provided, or use a medicine dose-measuring device (not a kitchen spoon).

Drink plenty of liquids to keep from getting dehydrated while you have diarrhea. Your doctor may recommend an electrolyte supplement such as Gatorade or Pedialyte. Carefully follow all care instructions.

It may take up to 48 hours before your symptoms improve. Keep using the medication as directed. Call your doctor if you still have diarrhea after 10 days, or if you have a fever.

Store at room temperature away from moisture and heat.

Keep this medicine where a child cannot reach it. An overdose of atropine and diphenoxylate can be fatal to a child.

Atropine and diphenoxylate dosing information

Usual Adult Dose for Diarrhea:

Initial dose: 2 tablets or 10 mL (5 mg of diphenoxylate), orally, 4 times a day
Maintenance dose: Once control is achieved, reduce dose to individual requirements, to as little as 2 tablets or 10 mL once a day
Maximum dose: 20 mg diphenoxylate per day

-Clinical improvement is usually seen within 48 hours.
-If no improvement is seen within 10 days, symptoms are unlikely to respond to further administration.

Usual Pediatric Dose for Diarrhea:

2 years and older:
Initial dose: 0.3 to 0.4 mg/kg of diphenoxylate, orally, in 4 divided doses
Maintenance dose: Once control is achieved, reduce dose to individual requirements, to as little as one quarter of the initial daily dosage
Maximum dose: 20 mg diphenoxylate per day

-These doses are approximate; adjust downward according to nutritional status and degree of dehydration.
-Reduce dose as soon as initial control of symptoms has been achieved.
-If no response within 48 hours, this medicine is unlikely to be effective.
-Use only the liquid medication in children under 13 years old; do not use tablets.

What happens if I miss a dose?

Take the medicine as soon as you can, but skip the missed dose if it is almost time for your next dose. Do not take two doses at one time.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222. An overdose of atropine and diphenoxylate can cause breathing problems and may result in death or permanent brain damage.

Early overdose symptoms include weakness, blurred vision, slurred speech, feeling hot, fast heartbeats, slowed breathing, fainting, seizure, or coma. Report any early overdose symptoms to your doctor as soon as possible.

What should I avoid while taking atropine and diphenoxylate?

Avoid driving or hazardous activity until you know how atropine and diphenoxylate will affect you. Your reactions could be impaired.

Avoid becoming overheated or dehydrated during exercise, in hot weather, or by not drinking enough fluids. Follow your doctor's instructions about the type and amount of liquids you should drink.

Drinking alcohol with this medicine can cause side effects.

What other drugs will affect atropine and diphenoxylate?

Using this medicine with other drugs that make you drowsy can worsen this effect. Ask your doctor before using opioid medication, a sleeping pill, a muscle relaxer, cold or allergy medicine, or medicine for anxiety, depression, or seizures.

Tell your doctor about all your other medicines. Some may affect atropine and diphenoxylate, especially:

This list is not complete. Other drugs may affect atropine and diphenoxylate, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible drug interactions are listed here.

Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.