Usage
Dicyclomine + Simethicone is prescribed to relieve symptoms associated with gastrointestinal spasms, bloating, and pain. This includes conditions like irritable bowel syndrome (IBS), infantile colic, and other functional bowel disorders characterized by cramps, flatulence, and abdominal discomfort. It is also used as adjunctive therapy in peptic ulcer disease.
It’s pharmacological classification is:
- Dicyclomine: Anticholinergic, Antispasmodic
- Simethicone: Anti-foaming agent
Mechanism of Action: Dicyclomine acts by inhibiting the action of acetylcholine, a neurotransmitter that stimulates muscle contractions in the gastrointestinal tract. This relaxes the smooth muscles of the GI tract, reducing spasms and pain. Simethicone works by reducing the surface tension of gas bubbles in the GI tract, allowing them to coalesce and be expelled more easily, thus relieving bloating and flatulence.
Alternate Names
There are no widely recognized alternate names for the combination product itself. However, the individual components are sometimes referred to as:
- Dicyclomine: Dicycloverine, Dicicloverina
- Simethicone: Activated dimethicone
Brand Names: The combination is available under various brand names like Colicspam, Meftal-Spas, and Axcel Dicyclomine-S (regional variations exist).
How It Works
Pharmacodynamics: Dicyclomine competitively inhibits the action of acetylcholine at muscarinic receptors, predominantly in the GI tract. This leads to smooth muscle relaxation and reduced GI motility and secretions. Simethicone is physiologically inert and not absorbed; it acts locally in the GI lumen by defoaming entrapped gas.
Pharmacokinetics: Dicyclomine is well absorbed orally. It is metabolized in the liver, primarily by CYP3A4 enzymes, and excreted mainly in the urine. Simethicone is not absorbed and is eliminated unchanged in the feces.
Mode of Action: Dicyclomine blocks acetylcholine binding to muscarinic M3 receptors on smooth muscle cells in the gut, inhibiting their contraction.
Elimination pathways: Dicyclomine is mainly excreted renally (via the kidneys). Simethicone is excreted unchanged in the feces.
Dosage
Standard Dosage
Adults:
10-20 mg of dicyclomine (often combined with 40-80 mg of simethicone per dose), orally, three to four times a day.
Children:
- 6 months - 2 years: 5-10 mg of dicyclomine, orally, three to four times a day (not to exceed 40 mg/day).
- 2-12 years: 5-10 mg of dicyclomine, orally, three to four times a day. Pediatric safety must be carefully considered, especially in infants younger than six months.
Special Cases:
- Elderly Patients: Start with a lower dose (10 mg dicyclomine) and adjust cautiously. Monitor renal function.
- Patients with Renal Impairment: Dose adjustment is usually required in patients with severe renal impairment.
- Patients with Hepatic Dysfunction: Use with caution due to the risk of impaired metabolism.
- Patients with Comorbid Conditions: Use with caution in patients with glaucoma, urinary retention, prostatic hyperplasia, tachycardia, or other cardiovascular conditions.
Clinical Use Cases
Dicyclomine + Simethicone’s use in these clinical settings is generally limited to addressing co-existing abdominal discomfort, gas, and spasms, and its use must be carefully evaluated:
- Intubation: Limited use; caution advised due to anticholinergic effects.
- Surgical Procedures: May be used pre-operatively to reduce secretions.
- Mechanical Ventilation: Limited use; consider potential for delayed gastric emptying.
- Intensive Care Unit (ICU) Use: Use with caution, consider potential for adverse effects in critically ill patients.
- Emergency Situations: Not typically indicated.
Dosage Adjustments
Adjustments are based on patient response, renal function, and hepatic function.
Side Effects
Common Side Effects
Dry mouth, blurred vision, dizziness, drowsiness, constipation, nausea, and urinary retention.
Rare but Serious Side Effects
Allergic reactions (rash, itching, swelling), difficulty breathing, rapid heart rate, confusion, hallucinations, and coma.
Long-Term Effects
Chronic constipation, cognitive impairment (with prolonged high doses), and potential for tolerance.
Adverse Drug Reactions (ADR)
Anaphylaxis, paralytic ileus, severe cardiovascular events, and acute angle-closure glaucoma.
Contraindications
Hypersensitivity to dicyclomine or simethicone, paralytic ileus, gastrointestinal obstruction, severe ulcerative colitis, toxic megacolon, unstable cardiovascular status, myasthenia gravis, closed-angle glaucoma, urinary retention, and infants under 6 months of age. Use with extreme caution in breast-feeding mothers.
Drug Interactions
Anticholinergics (additive effects), antidepressants (e.g., tricyclics, MAOIs), antihistamines, opioid analgesics, digoxin, antacids (reduced dicyclomine absorption), and potassium chloride. Alcohol can exacerbate drowsiness.
Pregnancy and Breastfeeding
- Pregnancy: Dicyclomine is Pregnancy Category B (animal studies show no risk, but human data limited). Simethicone is Pregnancy Category C. Use only if clearly needed and under medical supervision.
- Breastfeeding: Dicyclomine is excreted in breast milk and contraindicated while nursing. Simethicone’s safety during breastfeeding has not been established.
Drug Profile Summary
- Mechanism of Action: Dicyclomine: Anticholinergic, relaxes GI smooth muscle; Simethicone: Defoaming agent
- Side Effects: Dry mouth, blurred vision, dizziness, constipation, urinary retention
- Contraindications: Glaucoma, GI obstruction, myasthenia gravis, infants <6 months
- Drug Interactions: Other anticholinergics, antidepressants, antacids
- Pregnancy & Breastfeeding: Use with caution in pregnancy; contraindicated during breastfeeding
- Dosage: Adults: 10-20 mg PO TID-QID; Children: Dose adjustment required.
- Monitoring Parameters: Heart rate, blood pressure, GI symptoms, and cognitive function.
Popular Combinations
Dicyclomine is sometimes combined with other drugs like mefenamic acid for additional analgesic effects or with ranitidine for peptic ulcer disease.
Precautions
- General Precautions: Monitor for anticholinergic side effects. Use cautiously in elderly patients and those with pre-existing cardiovascular or GI conditions.
- Specific Populations: See above.
- Lifestyle Considerations: Avoid alcohol and activities requiring alertness.
FAQs (Frequently Asked Questions)
Q1: What is the recommended dosage for Dicyclomine + Simethicone?
A: Adults: 10-20 mg dicyclomine with 40-80mg simethicone, orally, three to four times a day. Pediatric and special population dosing requires adjustments.
Q2: What are the common side effects?
A: Dry mouth, blurred vision, dizziness, constipation, and urinary retention.
Q3: Is it safe to use during pregnancy or breastfeeding?
A: Use with caution during pregnancy only if absolutely necessary. Contraindicated during breastfeeding due to dicyclomine’s excretion in breast milk.
Q4: How does dicyclomine differ from simethicone in its action?
A: Dicyclomine is an antispasmodic that relaxes the gut muscles, while simethicone is an anti-foaming agent that helps expel trapped gas.
Q5: What conditions should be considered before prescribing this medication?
A: Glaucoma, urinary retention, prostatic hyperplasia, myasthenia gravis, GI obstruction, severe ulcerative colitis, and cardiovascular diseases.
Q6: Can Dicyclomine + Simethicone be used in infants?
A: Contraindicated in infants younger than six months due to the risk of serious adverse effects like seizures, respiratory failure, or even death.
Q7: Does this medication interact with other drugs?
A: Yes, it can interact with other anticholinergics, antidepressants, antacids, and certain other medications. Provide a complete medication history before prescribing.
Q8: What should patients be advised regarding lifestyle while taking this medication?
A: Avoid alcohol and activities requiring alertness due to potential drowsiness. Increase fluid and fiber intake to mitigate constipation.
Q9: Are there any long-term effects of using Dicyclomine + Simethicone?
A: Potential long-term effects can include chronic constipation and, with high doses, potential cognitive impairment. Tolerance to the antispasmodic effects can also develop with prolonged use.
Q10: What should be done in case of an overdose?
A: Immediately seek medical attention. Symptoms may include severe drowsiness, confusion, hallucinations, rapid heart rate, difficulty breathing, and coma. Supportive care and symptomatic treatment are essential.
