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

Other brand names: phenobarbital, hyoscyamine sulfate, atropine sulfate, scopolamine hydrobromide tablet

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 healthcare provider 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 Being chemically dependant on a drug means that there are physiologic reactions when the drug is withdrawn.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 healthcare provider if any of these conditions are occurring now or have occurred in the past:

  • Glaucoma
  • Obstructive uropathy
  • Obstructive disease of the gastrointestinal tract
  • Paralytic ileus, intestinal atony of the elderly or debilitated patient
  • Unstable cardiovascular status in acute hemorrhage
  • Severe ulcerative colitis especially if complicated by toxic megacolon
  • Myasthenia gravis
  • Hiatal hernia associated with reflux esophagitis
  • In patients with known hypersensitivity to any of the ingredients

Potential Side Effects of Donnatal

There are many adverse reactions to Donnatal, including but not limited to blurred vision, difficulty in urination, decreased sweating, nervousness, musculoskeletal pain, vomiting, headache, nausea, constipation, and weakness. If these symptoms occur after taking Donnatal, seek medical attention immediately. In addition, take care to stay hydrated while taking this drug, particularly in hot weather, because it can cause dehydration. 

Medications That Can Interact With Donnatal

Donnatal can interact with several drugs. Tell the prescribing healthcare provider 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 healthcare provider 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.

5 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. National Library of Medicine DailyMed. Donnatal.

  2. Herman MA, Roberto M. The addicted brain: understanding the neurophysiological mechanisms of addictive disorders. Front Integr Neurosci. 2015;9. doi:  10.3389/fnint.2015.00018

  3. National Library of Medicine MedlinePlus. Belladonna Alkaloid Combinations and Phenobarbital.

  4. National Library of Medicine DailyMed. Donnatal.

  5. National Library of Medicine MedlinePlus. Belladonna Alkaloid Combinations and Phenobarbital.

By Amber J. Tresca
Amber J. Tresca is a freelance writer and speaker who covers digestive conditions, including IBD. She was diagnosed with ulcerative colitis at age 16.