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Belladona/ Phenobarbital

Generic Name

belladonna (bell ah DON ah)
phenobarbital (feen oh BAR bit all)


Trade Name



What is belladonna/phenobarbital?

This combination acts on the muscle in the wall of the gut and also the urinary bladder. It relaxes the muscle and prevents spasms from occurring. It also can slightly reduce the production of stomach acid. There is also a sedative in the product since, in some instances, stress can aggravate intestinal spasm.


What is it used for?

The main role of this drug is to prevent painful spasm of the gut and urinary bladder. The following conditions may be helped: diarrhea, irritable or spastic bowel, diverticulosis, colic and urinary bladder spasm. At times, intestinal spasm is aggravated by stress so a sedative has been added to this product. It is seldom used in treating peptic ulcers since there are much better drugs now available to reduce stomach acid and heal ulcers.


How do I take it?

Follow your physician’s instructions carefully. Take belladonna/phenobarbital 30 to 60 minutes before eating for best results. Tablets may be crushed and capsules may be opened. The Extentabs should be swallowed whole. If you also take an antacid, take the antacid after the meal. Taking an antacid at the same time as belladonna/ phenobarbital can interfere with the absorption of this combination. Store at room temperature in a tightly sealed container. Keep all medications away from children. Never share your medications with anyone else.


What do I do for a missed dose?

If you miss a dose of this medicine, take it as soon as possible. If it is almost time for your next dose, skip the missed dose and return to your regular schedule. Do not double up on this medication.


Are there interactions with food or beverages?

There are no known food interactions with belladonna/phenobarbital. This drug can cause constipation which can be prevented by using foods rich in fiber and bran. Alcohol should be used with caution or avoided completely because the combination may cause excessive sedation.


Are there interactions with other drugs?

An interaction generally means that one drug may increase or decrease the effect of another drug. Also, the more medications a person takes, the more likely there will be a drug interaction.

Interactions with this drug may occur with the following:

  • monoamine oxidase (MAO) inhibitors (Nardil, Parnate)
  • sedatives (Ambien, Dalmane, Restoril)
  • antidepressants (Haldol, Elavil)
  • antacids
  • antihistamines (Benadryl)
  • cimetidine (Tagamet)
  • prednisone
  • blood thinners (Coumadin)
  • phenytoin (Dilantin)
  • gout medicine (probenecid)
  • narcotics (Percocet, Tylox)
  • digoxin (Lanoxin)
  • metoclopramide (Reglan)
  • thiazide diuretics (Dyazide, hydrochlorothiazide)
  • amantadine (Symmetrel)
  • cardiac rhythm regulators (Pronestyl, quinidine)
  • birth control pills


Is there a problem if I have another disorder or disease?

At times, a drug may have a different or enhanced effect when other diseases are present. At other times, the drug may worsen or effect another disease.

With this drug, the following disorders may be a problem:

  • glaucoma
  • prostate enlargement – BPH
  • hypertension (high blood pressure)
  • congestive heart failure
  • severe ulcerative colitis where bowel movements have stopped
  • myasthenia gravis
  • severe mental disorder
  • chronic or severe kidney or liver disease
  • asthma


What about allergies?

People who have known allergies or asthma may be at an increased risk for a reaction from any new medication. The physician should always know a patient’s allergy history. Signs of an allergic reaction are skin rash, hives and itching. Of course, a person should not take belladonna/phenobarbital if there has been a previous reaction to these or other anticholinergic drugs.


What if I’m pregnant, considering pregnancy or breast-feeding?

Most females now know that, if possible, no drug, including alcohol, should be taken during pregnancy or lactation. The potential danger, of course, is an injury to the baby. However, some drugs are much safer than others in this regard. So, the FDA has a grading system for each drug which reflects what is known medically. It ranks drugs from A, where medical studies show no evidence for danger to the fetus or mother, to B, C, D and X, where the medical evidence indicates that the risk to the fetus outweighs any benefit to the mother. Belladonna/phenobarbital is ranked C. Always consult your physician before taking any drug during or when planning pregnancy.


What are the effects on sexual function?

Belladonna/phenobarbital can cause impotence. In nursing mothers, it can cause suppression of breast milk. For women taking birth control pills, this medicine may decrease the effectiveness of your birth control pill. To prevent pregnancy, use an additional form of birth control for the duration of therapy.


Are there other precautions?

  • Belladonna/phenobarbital may make you dizzy, drowsy or blur your vision. Do not drive or operate hazardous machinery while taking this medication until the full effects of the drug have been determined.
  • This medication may decrease your ability to perspire. If you exercise in extremely hot weather, be aware of the possibility of heat stroke.
  • One of the ingredients is phenobarbital which can be habit forming. If you have ever been dependent on drugs, do not take this preparation.
  • Severe mental changes have occasionally been reported in individuals who are sensitive to this group of drugs. Symptoms include confusion, short-term memory loss, hallucinations or agitation. These symptoms usually resolve within 12 to 48 hours after discontinuation of the drug.


How long is it safe to take belladonna/phenobarbital?

It may take 4 to 5 days of regular use to determine the effectiveness of this drug. As long as the side effects are tolerable and there is no increase in the intensity of the side effects, this drug can be used long-term with physician supervision.


How about side effects?

Adverse reactions can occur with any drug, even over-the-counter medications. Some of these are mild such as a stomach upset, which may be avoided by taking the medication with food. Minor reactions may go away on their own but if they persist, contact the physician. For major reactions, the patient should contact the physician immediately.

For belladonna/phenobarbital, the following are the observed side effects:


  • headache
  • drowsiness
  • dizziness
  • rapid heartbeat
  • dry mouth
  • nausea
  • vomiting
  • rash
  • constipation


  • difficult urination
  • confusion
  • blurred vision


A physician’s comment…

This drug relieves symptoms. It does not cure an underlying disorder. The long-term use of any preparation containing phenobarbital is discouraged because of drug dependency. Some people have problems with constipation while taking this drug. The addition of fiber to the diet is helpful. Check with your physician on a regular basis.