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Bentyl Side Effects

Generic Name: dicyclomine

Note: This document contains side effect information about dicyclomine. Some of the dosage forms listed on this page may not apply to the brand name Bentyl.

For the Consumer

Applies to dicyclomine: oral capsules and tablets, oral solution, parenteral injection

Side effects include:

Most adverse effects are manifestations of pharmacologic effects at muscarinic-cholinergic receptors and usually are reversible when therapy is discontinued.

Severity and frequency of adverse effects are dose related and individual intolerance varies greatly; although adverse effects occasionally may be obviated by a reduction in dosage, this also will likely eliminate potential therapeutic effects. If dosage of ≥80 mg daily cannnot be achieved because of intolerance, discontinue dicyclomine (the active ingredient contained in Bentyl)

Dry mouth, dizziness, blurred vision, nausea, light-headedness (especially with the injectable form), drowsiness, weakness, nervousness.

For Healthcare Professionals

Applies to dicyclomine: compounding powder, intramuscular solution, oral capsule, oral syrup, oral tablet


-The most serious adverse reactions include cardiovascular and central nervous system symptoms.
-The most common adverse reactions are dizziness, dry mouth, vision blurred, nausea, somnolence, asthenia and nervousness, fever, tachycardia, agitation, and dry skin/mucous membranes.[Ref]


Very common (10% or more): Dry mouth (33%), nausea (14%)
Rare (less than 0.1%): Constipation, anorexia
Frequency not reported: Thirst, delayed gastric emptying time, reduced gastric acid secretion, gastroesophageal reflux
Postmarketing reports: Abdominal distension, abdominal pain, dyspepsia, constipation, dry mouth, nausea, vomiting[Ref]

Nervous system

Very common (10% or more): Dizziness (40%)
Common (1% to 10%): Somnolence, nervousness
Rare (less than 0.1%): Sedation, headache
Postmarketing reports: Dizziness, headache, somnolence, syncope[Ref]


Very common (10% or more): Blurred vision (27%)
Frequency not reported: Follicular conjunctivitis, all muscarinic antagonists can precipitate glaucoma
Postmarketing reports: Cycloplegia, mydriasis, blurred vision[Ref]


Common (1% to 10%): Asthenia
Frequency not reported: Fatigue
Postmarketing reports: Malaise, fatigue[Ref]


Rare (less than 0.1%): Rash
Postmarketing reports: Allergic dermatitis, erythema, rash[Ref]


Rare (less than 0.1%): Dysuria[Ref]


Frequency not reported: Urinary retention, impotence in male patients
Postmarketing reports: Suppressed lactation[Ref]


Postmarketing reports: Palpitations, tachyarrhythmias, thrombosis, thrombophlebitis[Ref]


Postmarketing reports: Face edema, angioedema, anaphylactic shock[Ref]


Postmarketing reports: Local pain, edema, skin color change, reflex sympathetic dystrophy syndrome (caused by inadvertent IV injection)[Ref]


Postmarketing reports: Delirium or symptoms of delirium such as amnesia (or transient global amnesia), nervousness, agitation, confusional state, delusion, disorientation, hallucination (including visual hallucination), and mania, mood (altered and pseudodementia).[Ref]


Postmarketing reports: Dyspnea, nasal congestion[Ref]


1. Kagan G, Huddlestone L, Wolstencroft P "Comparison of dicyclomine with antacid and without antacid in dyspepsia." J Int Med Res 12 (1984): 174-8

2. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0

3. "Product Information. Bentyl (dicyclomine)." Aventis Pharmaceuticals, Kansas City, MO.

Some side effects of Bentyl may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA.

Disclaimer: Every effort has been made to ensure that the information provided is accurate, up-to-date and complete, but no guarantee is made to that effect. In addition, the drug information contained herein may be time sensitive and should not be utilized as a reference resource beyond the date hereof. This material does not endorse drugs, diagnose patients, or recommend therapy. This information is a reference resource designed as supplement to, and not a substitute for, the expertise, skill , knowledge, and judgement of healthcare practitioners in patient care. The absence of a warning for a given drug or combination thereof in no way should be construed to indicate safety, effectiveness, or appropriateness for any given patient. does not assume any responsibility for any aspect of healthcare administered with the aid of materials provided. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the substances you are taking, check with your doctor, nurse, or pharmacist.