What You Need to Know About Donnatal (Belladonna/Phenobarbital)

Other brand names: Antispas, Barbidonna, Donnapine, Hyosophen, Spasmolin

Donnatal is a type of drug called an anticholinergic and is actually a combination of two drugs: belladonna and phenobarbital. It is used to relax the muscles in the bladder and the intestines as well as to reduce stomach acid. It's also important to know that phenobarbital is a mild sedative.

Woman holding medication
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The Habit-Forming Potential of Donnatal

Phenobarbital can be habit-forming. Donnatal may not be an appropriate treatment for people who have been dependant on other drugs. Before taking donnatal, talk to your doctor if you have had difficulty with drug dependence or alcoholism in the past. Being chemically dependant on a drug means that there are physiologic reactions when the drug is withdrawn.

How It's Taken

Donnatal should be taken one or two tablets three or four times a day according to condition and severity of symptoms. It should never be taken at the same time as antacids, as antacids can decrease the absorption of Donnatal.

Why It's Prescribed

Donnatal is used to treat irritable bowel syndrome (IBS). It may be prescribed for other conditions as well.

What to Do After Missing a Dose

If a dose is missed, it should be taken as soon as it is remembered. If the next dose should be taken soon, just take that dose. Don't double up, or take more than one dose at a time.

Who Should Not Take Donnatal

Before taking Donnatal, tell a doctor if any of these conditions are occurring now or have occurred in the past:

Potential Side Effects of Donnatal

The most serious side effects of Donnatal are confusion, blurred vision, difficulty in urination, and decreased sweating. If these symptoms occur after taking Donnatal, seek medical attention immediately. Take care to stay hydrated while taking this drug, particularly in hot weather, because it can cause dehydration.

Other common side effects that are usually not as serious include headache, nausea, constipation, rash, and vomiting. See a doctor if any of these side effects become severe or are bothersome.

Medications That Can Interact With Donnatal

Donnatal can interact with several drugs. Tell the prescribing physician about all drugs and nutritional supplements you are taking, especially those from the following list which may interact with Donnatal.

  • Antacids
  • Antidepressants
  • Antihistamines
  • Antispasmodics
  • Barbiturates
  • Birth Control Pills
  • Blood-thinning drugs (Coumadin)
  • Cimetidine (Tagamet)
  • Diarrhea medications containing Kaolin or attapulgite
  • Digitalis (Lanoxin)
  • Metoclopramide (Reglan)
  • Monoamine oxidase (MAO) inhibitors
  • Narcotics
  • Potassium chloride
  • Prednisone
  • Sedatives
  • Thiazide diuretics

Potential Food Interactions

Consuming alcohol while taking Donnatal could increase the sedative effect and cause tiredness or sleepiness. Take care to avoid alcohol from unexpected sources, such as over the counter cough suppressants or cold products (Nyquil, for example).

Safety During Pregnancy

Donnatal can cause fetal harm when administered to a pregnant woman. Animal reproduction studies have not been conducted with Donnatal.

Donnatal should be avoided during pregnancy. Women should call their doctor upon becoming pregnant while taking Donnatal. The potential for serious side effects in an infant should be weighed against the usefulness of the medication to the mother.

Potential Sexual Side Effects

Donnatal can cause impotence in men, and suppression of breast milk in nursing mothers. It may also decrease the effectiveness of birth control pills.

A Word From Verywell

Donnatal can be helpful in relieving pain or discomfort for people who are living with bowel and bladder conditions. However, it does carry a risk of dependency, which may mean that it is not a good choice for people who have experienced chemical dependency in the past. This drug is usually prescribed to be taken when it is needed, such as after a meal. In the beginning, it may be helpful to take this drug at night to see if it causes a sedative effect. Once the potential side effects are better understood, it may be possible to take this drug at other times if it doesn't cause drowsiness.

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  1. National Institute of Health. Donnatal.