What Are Antispasmodics?
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Antispasmodics - Uses, Side Effects, Precautions, and Interactions

Published on Nov 11, 2022 and last reviewed on May 10, 2023   -  4 min read


Antispasmodics are drugs used to treat medical conditions involving muscle contraction and relaxation. To learn more about it, read below.

What Are Antispasmodics?

Antispasmodics are a heterogeneous group of drugs used for the symptomatic treatment of cramping and discomfort affecting the smooth muscles of the gastrointestinal, biliary, or genitourinary tract. These drugs relieve, prevent, or lower the incidence of muscle spasms, especially in the smooth muscles of the bowel wall. Antispasmodics, also called Anticholinergics, are a broad group of medicines that act on the neurotransmitter, acetylcholine.

There are two types of antispasmodics - Antimuscarinics such as Dicycloverine, Atropine, Propantheline, and Hyoscine. The other antispasmodics are Smooth muscle relaxants such as Alverine, Mebeverine, and peppermint oil.

How Do Antispasmodics Work?

Antispasmodics work by blocking the action of acetylcholine in the brain and the parasympathetic nerves. These drugs prevent the binding of acetylcholine to the neurotransmitters on the surface of the nerves, muscles, and glands. This prevents impulses from the nervous system from reaching smooth muscles and causing contractions and spasms.

Anticholinergic drugs also decrease the activity of the muscles in the gut and reduce the production of sweat, saliva, digestive juices, urine, and tears. These drugs help to balance the production of dopamine neurotransmitters. And play an important role in maintaining mood, memory, and motivation.

What Are Antispasmodics Used For?

Antispasmodics are commonly used to help relieve symptoms of irritable bowel syndrome (IBS) such as spasms, bloating, and abdominal pain. They help to reduce the movement of the gastrointestinal tract. The drug also helps to reduce anxiety as it acts on the brain to produce a calming effect. Antispasmodics are used together with antacids for the treatment of peptic ulcers. They can be used to prevent nausea, vomiting, and motion sickness. Antispasmodics are indicated in chronic obstructive pulmonary disease (COPD) and asthma.

How to Use Antispasmodics?

It is generally recommended to take the medicines only when necessary and as advised by the doctor. Antispasmodics should be taken at a particular time and may be taken with or without food. It is advised to take it at least two hours apart from antacids as they lower the absorption of antispasmodics. The dose should not be increased without consulting the doctor. The medication should not be stopped suddenly as there may be withdrawal symptoms such as anxiety, nausea, vomiting, and muscle twitching.

Antispasmodics usually work within an hour after oral administration. Their effectiveness depends on the dosage and the frequency. The medication may be taken for two weeks. Antispasmodics such as Dicyclomine are given in injection form intramuscularly and should be used only for one to two days.

What Is the Dosage of Antispasmodics?


Missed Dose:

If you miss a dose of antispasmodics, take it as soon as you remember. However, if it is almost time for the next dose, skip it. Follow your regular dosing schedule. You should avoid doubling the dose as it may lead to adverse reactions.

What Are the Precautions and Warnings for Using Antispasmodics?

Before starting the antispasmodics, it is advised to inform your doctor if you have any of the following conditions:

  • Allergies - It is important to inform the doctor if you have had allergic reactions to antispasmodics or other medicines, foods, dyes, preservatives, or animals.

  • Pediatric - Children sensitive to belladonna alkaloids may experience unusual excitement, nervousness, restlessness, or irritability.

  • Geriatrics - Antispasmodics may cause memory loss, constipation, difficulty urination, dryness of mouth, or eye pain in the elderly and should be given with caution.

  • Pregnancy and Breastfeeding - The drug is not recommended for use during pregnancy as it may harm the unborn baby. Antispasmodics pass into the breast milk and can have undesirable effects on the baby.

  • Liver Disease - The medication should be used with caution in patients with impaired liver function.

  • Kidney Disease - Antispasmodics should be used with caution in patients with impaired kidney function.

  • Alcohol - Alcohol may increase side effects like dizziness, drowsiness, and difficulty concentrating.

  • Addiction - Antispasmodics should be taken with caution in patients with a history of drug abuse as it may cause addiction. Hence it should be taken as prescribed by the doctor.


In case of an overdose, the patient should consult a doctor immediately. It may cause restlessness, dizziness, and confusion, which may require gastric lavage.

What Are the Interactions of Antispasmodics?

With Other medicines:

  • Darunavir.

  • Etravirine.

  • Potassium.

  • Sodium oxybate.

  • Ketoconazole.

  • Phenobarbitone.

  • Sorafenib.

  • Voriconazole.

  • Boceprevir.

  • Rilpivirine.

With Food:

The administration of antispasmodics with grapefruit juice may delay and increase the bioavailability of the drug.

With Disease:

  • Cardiovascular Disease - The intravenous administration may produce severe cardiovascular reactions such as bradycardia, and hypertension.

  • Renal Dysfunction - Injectable antispasmodics are contraindicated in patients with impaired renal function due to nephrotoxic potential and preexisting acidosis and urea retention.

  • Seizures - Antispasmodics should be administered with caution in patients with a history of epilepsy.

What Are the Side Effects of Antispasmodics?

The common side effects include

  • Constipation.

  • Decreased sweating.

  • Dizziness.

  • Dry mouth, nose, throat, or skin.

Rare side effects may include,

  • A bloated feeling.

  • Blurred vision.

  • Headache.

  • Loss of memory.

  • Difficult urination.

  • Decreased flow of breast milk.

  • Confusion.

  • Fainting.


Antispasmodic medicines are used to treat symptoms such as stomach pain and cramps. They are more effective at relieving symptoms in certain surgical and emergency procedures. Antispasmodics are mostly available only with a doctor’s prescription and should be used judiciously and only when you have active symptoms.

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Last reviewed at:
10 May 2023  -  4 min read




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