- Irritable Bowel Syndrome (IBS) Slideshow Pictures
- Digestive Disease Myths
- Irritable Bowel Syndrome (IBS) Quiz
- Dicyclomine vs. Donnatal: What's the difference?
- What is dicyclomine? What is Donnatal?
- What are the side effects of dicyclomine and Donnatal?
- What is the dosage of dicyclomine vs. Donnatal?
- What drugs interact with dicyclomine and Donnatal?
- Are dicyclomine and Donnatal safe to use while pregnant or breastfeeding?
Dicyclomine vs. Donnatal: What's the difference?
- Dicyclomine and Donnatal (belladonna/phenobarbital) are used to treat irritable bowel syndrome (IBS).
- Dicyclomine and Donnatal belong to different drug classes. Dicyclomine is an anticholinergic and Donnatal is a combination of an anticholinergic/antispasmodic.
- A brand name for dicyclomine is Bentyl.
- Side effects of dicyclomine and Donnatal that are similar include dry mouth, blurred vision, increased heart rate, heart palpitations, constipation, difficulty urinating, headache, nervousness, drowsiness, and dizziness.
- Side effects of dicyclomine that are different from Donnatal include confusion, agitation, seizures, changes in taste, difficulty swallowing, weakness, impotence, flushing, delirium, difficulty falling asleep (insomnia), nausea, vomiting, rash, skin redness, fainting, bloating, and difficulty breathing.
- Side effects of Donnatal that are different from dicyclomine include dry eyes.
What is dicyclomine? What is Donnatal?
Dicyclomine is an anticholinergic used to treat irritable bowel syndrome (IBS). Anticholinergic drugs block the effects of acetylcholine, the chemical transmitter that nerves release in order to cause muscles to contract. They prevent contraction of muscles by blocking the acetylcholine receptors on the muscle cells. Anticholinergic drugs also have a direct relaxing effect on muscle. Dicyclomine is used to reduce contraction of the muscles in the intestines.
Donnatal (belladonna/phenobarbital) is a combination of an anticholinergic/antispasmodic drug and a barbiturate sedative used to treat symptoms of abdominal pain, bloating, and cramps in patients with irritable bowel syndrome (IBS). Donnatal is also used to treat acute inflammation of the stomach and intestines (gastroenteritis) to reduce pain and diarrhea, and in patients with duodenal ulcer. Belladonna alkaloids block the action of acetylcholine, a chemical that nerves to use to communicate with other nerves and muscles. Acetylcholine stimulates the muscles of the intestines that propels digesting food through the intestine. It also affects the secretion of fluids by salivary glands and the stomach. By blocking acetylcholine, belladonna alkaloids relax intestinal muscles, slow passage of digesting food through the intestines, and reduce gastric secretion. Phenobarbital produces sedation.

SLIDESHOW
Digestive Disorders: Common Misconceptions See SlideshowWhat are the side effects of dicyclomine and Donnatal?
Dicyclomine
Common side effects include:
- dry mouth (xerostomia),
- blurred vision,
- confusion,
- agitation,
- increased heart rate,
- heart palpitations,
- constipation,
- difficulty urinating, and
- seizures.
Other important side effects include:
- changes in taste perception,
- difficulty swallowing,
- headache, nervousness,
- drowsiness,
- weakness,
- dizziness,
- impotence,
- flushing,
- delirium,
- difficulty falling asleep,
- nausea,
- vomiting,
- rash,
- erythema,
- fainting,
- bloating, and
- difficulty breathing.
Donnatal
Adverse reactions include:
- constipation;
- dry eyes;
- dry mouth;
- urinary hesitancy and retention (difficulty urinating, particularly in men);
- blurred vision;
- rapid heart rate;
- palpitations;
- headache;
- nervousness;
- drowsiness; and
- dizziness
Caution is advised in patients with glaucoma, myasthenia gravis and urinary obstruction since symptoms of these conditions may worsen with the use of belladonna/phenobarbital. Patients with an unstable cardiac status, severe ulcerative colitis and acute intermittent porphyria should avoid belladonna/phenobarbital. Elderly patients may experience confusion, depression, and excitement even from small doses.
What is the dosage of dicyclomine vs. Donnatal?
Dicyclomine
The recommended starting oral dose of dicyclomine is 20 mg given 4 times daily. The dose can be increased to 40 mg 4 times daily. The recommended intramuscular injection is 10 to 20 mg 4 times daily. The intramuscular injection is only used for 1 to 2 days if a patient cannot take capsules or tablets.
Donnatal
May be taken with or without food. The dosage is adjusted to the individual patient to assure control of symptoms with a minimum of side effects. The usual doses are 1-2 regular tablets 3 to 4 times daily or 1 extended release tablet every 8 or 12 hours or 5-10 ml of the elixir, 3 or 4 times daily.
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What drugs interact with dicyclomine and Donnatal?
Dicyclomine
Antiglaucoma Agents
Anticholinergics antagonize the effects of antiglaucoma agents and may increase intraoccular pressure. Anticholinergic drugs in the presence of increased intraocular pressure may be hazardous when taken concurrently with agents such as corticosteroids. Use of Bentyl in patients with glaucoma is not recommended.
Other Drugs with Anticholinergic Activity
The following agents may increase certain actions or side effects of anticholinergic drugs including Bentyl:
- amantadine,
- antiarrhythmic agents of Class I (for example, quinidine),
- antihistamines,
- antipsychotic agents (for example, phenothiazines),
- benzodiazepines,
- MAO inhibitors,
- narcotic analgesics (for example, meperidine),
- nitrates and nitrites,
- sympathomimetic agents,
- tricyclic antidepressants, and
- other drugs having anticholinergic activity.
Other Gastrointestinal Motility Drugs
Interaction with other gastrointestinal motility drugs may antagonize the effects of drugs that alter gastrointestinal motility, such as metoclopramide.
Effect of Antacids
Because antacids may interfere with the absorption of anticholinergic agents including Bentyl, simultaneous use of these drugs should be avoided.
Effect on Absorption of Other Drugs
Anticholinergic agents may affect gastrointestinal absorption of various drugs by affecting on gastrointestinal motility, such as slowly dissolving dosage forms of digoxin; increased serum digoxin concentration may result.
Effect on Gastric Acid Secretion
The inhibiting effects of anticholinergic drugs on gastric hydrochloric acid secretion are antagonized by agents used to treat achlorhydria and those used to test gastric secretion.
Donnatal
Phenobarbital reduces the blood levels of several drugs by increasing their breakdown in the body. Examples include voriconazole (Vfend), bocepravir (Victrelis), ranolazine (Ranexa), and protease inhibitors (for example, atazanavir [Reyataz], indinavir [Crixivan], saquinavir [Invirase], ritonavir [Norvir]). Belladonna/phenobarbital should not be combined with potassium tablets because belladonna/phenobarbital slows the passage of potassium tablets through the gastrointestinal tract, leading to potassium-induced ulcers and high potassium levels in the blood.

QUESTION
What is irritable bowel syndrome or IBS? See AnswerAre dicyclomine and Donnatal safe to use while pregnant or breastfeeding?
Dicyclomine
There are no adequate studies of the effect of dicyclomine in pregnant women at recommended doses (80-160 mg/day). Observation of women who received dicyclomine (up to 40 mg/day) containing products during the first trimester of pregnancy did not reveal any increased risk of harm to the fetus.
Dicyclomine is excreted into breast milk. Since there have been reports of apnea (cessation of breathing) when dicyclomine has been given to children, it should not be used by nursing mothers.
Donnatal
Use during pregnancy has not been adequately evaluated. Pregnant women should use belladonna alkaloid/phenobarbital only when the expected benefit outweighs the potential but unknown risks. Belladonna/phenobarbital are secreted in breast milk and may also reduce milk production.
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Summary
Dicyclomine and Donnatal (belladonna/phenobarbital) are used to treat irritable bowel syndrome (IBS). Dicyclomine and Donnatal belong to different drug classes. Dicyclomine is an anticholinergic and Donnatal is a combination of an anticholinergic/antispasmodic.
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Related Disease Conditions
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Inflammatory Bowel Disease (IBD)
The inflammatory bowel diseases (IBD) are Crohn's disease (CD) and ulcerative colitis (UC). The intestinal complications of Crohn's disease and ulcerative colitis differ because of the characteristically dissimilar behaviors of the intestinal inflammation in these two diseases.
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Inflammatory Bowel Disease (IBD) Diet
Inflammatory bowel disease (IBD) is a name for a group of diseases in which there is inflammation of the digestive tract (gastrointestinal tract). Crohn's disease and ulcerative colitis (UC) are the most common types of inflammatory bowel disease. While there is no specific recommended diet for a person with IBD, doctors and specialists recommend a low-residue (low fiber) diet for people with inflammatory bowel disease. Nutritionists, registered dieticians, and other health-care professionals can recommend specific foods, create meal plans, and recommend vitamins and other nutritional supplements.Foods to avoid with IBDExamples of foods to avoid that may trigger symptoms include if you have IBD include products alcohol, diary products, fatty, fried, and spicy foods, beans, and creamy sauces. Foods to eat with IBD Examples of a low-residue (low-fiber) diet that may help relieve symptoms after a flares of the disease are plain cereals, canned fruit, rice, oatmeal, and bananas.
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IBS vs. IBD: Differences and Similarities
IBS (irritable bowel syndrome) and IBD (inflammatory bowel disease) are both problems with the digestive tract (gastrointestinal or GI tract), but they are not the same disease. IBS is a functional disorder (a problem with the way the GI tract functions), and IBD is a disease that causes chronic prolonged inflammation of the GI tract, that can lead to ulcers and other problems that may require surgery. The most common forms of IBD are Crohn's disease and ulcerative colitis, or UC. Researchers do not know the exact cause of either disease, but they believe that IBS may be caused and triggered by a variety of factors (foods, stress, and the nervous system of the GI tract), while IBD may be genetic or due a problem with the immune system.Common symptoms of both diseases are an urgent need to have a bowel movement, diarrhea, nausea, vomiting, and abdominal pain and cramping. There are differences between the signs and symptoms of irritable bowel syndrome and inflammatory bowel disease, for example, symptoms unique to IBD are: Fever Joint pain or soreness Skin changes Rectal bleeding Anemia Eye redness or pain Unintentional weight loss Feeling tired Symptoms unique to irritable bowel syndrome include: Sexual problems Fibromyalgia Abdominal bloating Whitish mucous in the stool Changes in bowel movements and in the way stools look An urgent need to urinate Urinating frequently Treatment for IBS is with diet recommendations from a doctor or nutritionist, medication, and lifestyle changes like stress management and avoiding foods that trigger the condition. Treatments for IBD depend upon the type of disease, its symptoms, and health of the patient. Surgery may be necessary for some individuals.REFERENCES: Brown, AC, et al. "Existing Dietary Guidelines for Crohn's Disease and Ulcerative Colitis." Medscape. Lehrer, J. "Irritable Bowel Syndrome." Medscape. Updated: Apr 04, 2017. Rowe, W. "Inflammatory Bowel Disease." Medscape. Updated: Jun 17, 2016. Romanowski, A, MS, RD. "Matching the Right Diet to the Right Patient." Medscape. Jan 27, 2017.
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Drug interaction section for dicyclomine courtesy of the U.S. Food and Drug Administration