Dicyclomine vs. Hyoscyamine

What's the Difference?

Dicyclomine and Hyoscyamine are both medications used to treat various gastrointestinal conditions, such as irritable bowel syndrome (IBS). They belong to the same class of drugs called anticholinergics, which work by relaxing the smooth muscles in the digestive tract. However, there are some differences between the two. Dicyclomine is primarily used to relieve symptoms of IBS, such as abdominal pain and cramping, while Hyoscyamine is also used to treat other conditions like peptic ulcers and urinary incontinence. Additionally, Dicyclomine is available in both oral tablet and injectable forms, while Hyoscyamine is commonly taken orally in tablet or sublingual form. Overall, both medications can be effective in managing gastrointestinal symptoms, but the choice between them may depend on the specific condition being treated.


Chemical FormulaC19H35NO2C17H23NO3
Brand NamesBentyl, Dibent, ByclomineLevsin, Anaspaz, Cystospaz
Medical UsesTreatment of irritable bowel syndrome (IBS), stomach cramps, and intestinal spasmsTreatment of irritable bowel syndrome (IBS), bladder spasms, and gastrointestinal disorders
Mode of ActionAnticholinergic and antispasmodic effects by blocking muscarinic receptorsAnticholinergic and antispasmodic effects by blocking muscarinic receptors
Side EffectsDrowsiness, dizziness, dry mouth, blurred visionDrowsiness, dizziness, dry mouth, blurred vision
ContraindicationsGlaucoma, myasthenia gravis, severe ulcerative colitisGlaucoma, myasthenia gravis, severe ulcerative colitis

Further Detail


Dicyclomine and Hyoscyamine are both medications that belong to the class of anticholinergic drugs. They are commonly prescribed to treat various gastrointestinal conditions, such as irritable bowel syndrome (IBS) and functional bowel disorders. While they share similarities in their mechanism of action and therapeutic uses, there are also notable differences in their pharmacokinetics, side effects, and dosing regimens. This article aims to provide a comprehensive comparison of the attributes of Dicyclomine and Hyoscyamine.

Mechanism of Action

Both Dicyclomine and Hyoscyamine exert their therapeutic effects by blocking the action of acetylcholine, a neurotransmitter that plays a crucial role in the contraction of smooth muscles in the gastrointestinal tract. By inhibiting the binding of acetylcholine to its receptors, these medications help relax the smooth muscles, thereby reducing spasms and relieving symptoms associated with gastrointestinal disorders.


Dicyclomine is rapidly absorbed after oral administration, with peak plasma concentrations reached within 1-2 hours. It undergoes extensive metabolism in the liver and has a half-life of approximately 1-2 hours. On the other hand, Hyoscyamine is also well absorbed orally, with peak plasma concentrations achieved within 1-2 hours. It undergoes hepatic metabolism and has a longer half-life of around 3-4 hours. These differences in pharmacokinetics may influence the dosing frequency and duration of action of the two medications.

Therapeutic Uses

Dicyclomine and Hyoscyamine are primarily indicated for the treatment of irritable bowel syndrome (IBS) and functional bowel disorders characterized by abdominal pain, cramping, and bowel irregularities. They help alleviate symptoms such as abdominal discomfort, bloating, and diarrhea by reducing gastrointestinal spasms. Additionally, these medications may also be used to manage other conditions, including peptic ulcers, diverticulitis, and urinary incontinence.

Side Effects

While Dicyclomine and Hyoscyamine are generally well-tolerated, they can cause certain side effects due to their anticholinergic properties. Common side effects of both medications include dry mouth, blurred vision, dizziness, and constipation. These effects are a result of the inhibition of acetylcholine in various parts of the body, including salivary glands, tear ducts, and smooth muscles. It is important to note that individual responses to these medications may vary, and some individuals may experience more pronounced side effects than others.

Dosing Regimens

The dosing regimens for Dicyclomine and Hyoscyamine differ slightly. Dicyclomine is typically administered as 10-20 mg tablets, to be taken orally 3-4 times a day before meals and at bedtime. The total daily dose should not exceed 80 mg. On the other hand, Hyoscyamine is available in various formulations, including sublingual tablets, extended-release capsules, and oral solutions. The recommended starting dose for Hyoscyamine is usually 0.125-0.25 mg taken orally 3-4 times a day, with a maximum daily dose of 1.5 mg.

Drug Interactions

Both Dicyclomine and Hyoscyamine may interact with other medications, potentially altering their effectiveness or increasing the risk of side effects. It is important to inform healthcare providers about all the medications, supplements, and herbal products being taken to avoid potential interactions. Dicyclomine may interact with certain antacids, antidiarrheal agents, and medications that affect the central nervous system. Hyoscyamine, on the other hand, may interact with drugs that have anticholinergic effects, such as antihistamines and tricyclic antidepressants.


Dicyclomine and Hyoscyamine are both valuable medications in the management of gastrointestinal disorders, particularly irritable bowel syndrome. While they share a common mechanism of action, their pharmacokinetics, side effects, and dosing regimens differ. Understanding these attributes is crucial for healthcare providers to make informed decisions when prescribing these medications. It is important for patients to communicate any concerns or side effects experienced while taking these medications to their healthcare providers for appropriate management. Overall, both Dicyclomine and Hyoscyamine offer effective relief for individuals suffering from gastrointestinal spasms and associated symptoms.

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