Gastroenterology: Medications

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Intestinal Antispasmodics

Many patients are not as well-informed about prescription medications as they ought to be. We believe that the more you know about your medications, the better. Therefore, we have written this leaflet to explain more about Intestinal Antispasmodics and to explain the importance of taking them properly.

If any of this information causes you concern or if you want additional information about your medicine and its use, please check with your doctor or pharmacist.

Remember to keep all prescription drugs beyond the sight and reach of children when not in use. Store all drugs in their original labeled containers; the place of storage should be cool, dry, and away from light. Always read the label before each use.

What are Antispasmodics?

Available since the 1950's, antispasmodic medications are derivatives of belladonna, a plant commonly used in the 18th century as a remedy for intestinal disorders. They all act to relax the muscles in the wall of the intestines and also the urinary bladder - prevents spasms from occurring. They also can slightly reduce the production of stomach acid. Newer man-made formulations are useful in treating symptoms such as abdominal pain, cramping, and diarrhea that result from spasm in the gastrointestinal tract. Antispasmodic medications are also commonly used to treat conditions such as irritable bowel syndrome. They are seldom used to treat peptic ulcers since there are now much better drugs available to reduce stomach acid and heal ulcers.

There are literally dozens of intestinal antispasmodics on the market. Common brand names include:

  • Anaspaz (hyoscyamine)
  • Bentyl (dicyclomine)
  • Librax (chlordiazepoxidem/clindium)
  • LevBid (hyoscyamine)
  • Levsin (hyoscyamine)
  • Levsinex (hyoscyamine)
  • NuLev (hyoscyamine)
  • Pro-Banthine (propantheline)
  • Robinul (glycopyrrolate)


  • What Antispasmodics are not.

    Antispasmodics do not heal or cure any disease process. They merely control symptoms. Since simple antispasmodics are not habit-forming, they can be taken indefinitely.

    Often, antispasmodics are combined with mild tranquilizers to boost their effectiveness. These "combination" drugs such as Donnatal are more effective in reducing intestinal spasms. However, they are potentially habit-forming when taken regularly for extended periods of time.

    How do Antispasmodics work?

    Although the process of how antispasmodics work is uncertain, it is known that these medications help reduce intestinal spasm by blocking nerve impulses from the brain and spinal cord to the intestinal wall.

    Taking Antispasmodics properly.

    • Take the dose as prescribed. There is no fixed rule for the correct dose of these drugs. Each case is different. As with all medications, the goal is to effectively control your symptoms with the lowest possible dose of medication. Your doctor will determine what initial dose is best for you on the basis of your age, weight, the severity of your symptoms, and any other medical conditions that you may have. After evaluating your response to treatment, your doctor will make adjustments in dosage as needed. Do not increase the dose on your own.
    • Antispasmodics are best taken 30 minutes before meals. This allows them to be most active when your digestive system is working. They can be taken either on an empty stomach or with food or milk. Avoid taking them at the same time as an antacid. A bedtime dose is sometimes prescribed. Since alcohol may increase or prolong the sedative effects of these drugs, it should be avoided. Otherwise, there are no food or beverage restrictions due to antispasmodics.
    • If you forget a dose, take the normal dose of the medication as soon as you remember. Then resume your normal schedule. If your next dose is within 2 hours, skip the missed dose. While an occasional extra dose is unlikely to cause problems, it may lead to excessive drowsiness. Do not intentionally double dose.
    • It is permissible to stop taking this medication on your own. Since antispasmodics act only to control symptoms, you may stop taking the medication once your symptoms have improved. You may then resume the medication as needed to control symptoms. As long as the side effects are tolerable, these drugs can be used long-term with physician supervision.
    What are the side effects?

    All medicines, even those purchased without a prescription, may sometimes produce unwanted side effects. Fortunately, serious side effects are rare. In general, the risk of side effects depends on the dosage of medication. It is important that you keep all your appointments with your doctor so that he can be sure the medication is working and check for possible side effects. Use caution when driving or performing tasks requiring alertness. This medication reduces sweating which can lead to heat stroke in hot weather. Avoid strenuous activity in hot weather.

    These side effects should be reported to your doctor:

    • Skin rash, severe itching
    • Unusual bleeding or bruising
    • Confusion
    • Tremors
    • Blurred vision
    • Difficulty urinating
    • Irregular or rapid pulse
    • Difficulty breathing
    • Severe constipation
    The following side effects usually do not require medical attention. They often will go away as the dosage is reduced or as your body becomes accustomed to the medication. However, if any of these side effects persist or are bothersome, simply check with your doctor:
    • Dizziness
    • Fatigue
    • Dryness of mouth, nose, and throat
    • Mild constipation
    • Light sensitivity caused by dilation of the pupils
    • Decreased sweating with exercise/overheating
    • Slightly increased heart rate
    Occasionally, patients experience side effects not listed above. If you notice any other effects, check with your doctor, nurse, or pharmacist.


    Do not take antispasmodics if you have a history of severe prostate problems or difficulty with urination. If you develop difficulty urinating while taking this medication, stop it and call your doctor for instructions. You should also avoid antispasmodics if you suffer from chronic constipation, glaucoma, or myasthenia gravis. Use with caution in hot environments.

    Tell your doctor if you are breast-feeding, pregnant or planning to become pregnant in the near future. Although there is no evidence that simple antispasmodics are harmful during lactation and pregnancy, we feel it is best to avoid all prescription drugs during these times.

    Since antispasmodics can cause drowsiness in some patients, you should avoid driving or operating machinery until you have determined if this drug affects you in this manner. Avoid alcohol while taking antispasmodics.


    Antispasmodics are powerful drugs that have many beneficial effects. As with all medications, side effects may occur. You can best limit problems with antispasmodics by taking them exactly as prescribed. If you have any questions or concerns, do not hesitate to consult your doctor.

    Text & Images Courtesy of Three Rivers Endoscopy Center
    © Dr. Robert Fusco, Three Rivers Endoscopy Center, All Rights Reserved

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