Dicyclomine (10mg/5ml) + Dimethicone (40mg/5ml)

Clinical Pharmacologist's Monograph

⚠️ Prescription Only: This medicine is Schedule H/H1. Do not self-medicate.

1. Clinical Overview

A fixed-dose combination oral suspension containing an antispasmodic agent (Dicyclomine) and an antiflatulent agent (Dimethicone). Dicyclomine is an anticholinergic that relieves smooth muscle spasm in the gastrointestinal tract, while Dimethicone is a silicone polymer that reduces surface tension of gas bubbles, aiding in their coalescence and expulsion. This combination is widely used in India for symptomatic relief of abdominal pain, bloating, and discomfort associated with functional gastrointestinal disorders like Irritable Bowel Syndrome (IBS) and functional dyspepsia.

OnsetDurationBioavailability
Dicyclomine: 1-2 hours; Dimethicone: Acts locally, onset within minutes of reaching the gut.Dicyclomine: 4-6 hours; Dimethicone: Transient, requires repeated dosing with meals.Dicyclomine: Approximately 67% after oral administration. Dimethicone: Not systemically absorbed; acts locally in the GI tract.

2. Mechanism of Action

Dicyclomine competitively inhibits muscarinic acetylcholine receptors (M1, M2, M3) on smooth muscle cells in the gastrointestinal tract, leading to direct smooth muscle relaxation. It also has a direct papaverine-like spasmolytic effect. Dimethicone is a physiologically inert silicone oil with defoaming properties. It reduces the surface tension of gas bubbles trapped in the GI mucus and chyme, causing them to coalesce. This allows the gas to be more easily expelled via belching or flatus, relieving bloating and discomfort.

3. Indications & Uses

  • Symptomatic relief of abdominal pain and discomfort in Irritable Bowel Syndrome (IBS)
  • Symptomatic relief of abdominal colic and bloating associated with functional gastrointestinal disorders

4. Dosage & Administration

Adult Dosage: 10 ml (containing Dicyclomine 20mg + Dimethicone 80mg) three to four times daily, preferably 20-30 minutes before meals and at bedtime. The dose may be adjusted based on response, but total Dicyclomine should not exceed 160mg/day.

Administration: Shake the bottle well before use. Use the measuring cup or spoon provided. Can be taken with or without food, but taking 20-30 minutes before meals may provide better prophylactic relief for postprandial symptoms. Do not dilute. Follow with a glass of water if desired.

5. Side Effects

Common side effects may include:

  • Dry mouth
  • Blurred vision/cycloplegia
  • Drowsiness/dizziness
  • Constipation
  • Nausea
  • Palpitations
  • Decreased sweating

6. Drug Interactions

DrugEffectSeverity
Other Anticholinergics (e.g., Atropine, Oxybutynin, TCAs, Antihistamines)Additive anticholinergic side effects (dry mouth, constipation, urinary retention, confusion, tachycardia).Major
AmantadineIncreased anticholinergic side effects.Moderate
Potassium Chloride (wax-matrix tablets)Dicyclomine may reduce GI motility, increasing risk of GI mucosal lesions from KCl.Moderate
Metoclopramide, DomperidonePharmacological antagonism; Dicyclomine reduces GI motility, counteracting prokinetic effects.Moderate
Opioid Analgesics (e.g., Codeine, Tramadol)Additive constipation and CNS depression.Moderate
Benzodiazepines, Alcohol, CNS DepressantsAdditive sedative effects, increased drowsiness and dizziness.Moderate
DigoxinReduced GI motility may increase digoxin absorption, potentially leading to toxicity.Moderate
Antacids, KaolinMay reduce absorption of Dicyclomine. Administer at least 1-2 hours apart.Minor
Monoamine Oxidase Inhibitors (MAOIs)May intensify anticholinergic effects.Moderate

7. Patient Counselling

  • DO take the exact dose prescribed by your doctor.
  • DO shake the bottle well before each use.
  • DO use the measuring device provided with the medicine.
  • DO inform your doctor if you are pregnant, planning pregnancy, or breastfeeding.
  • DO inform your doctor about all other medicines you are taking.
  • DONT drive or operate heavy machinery if you feel drowsy or dizzy.
  • DONT take this medicine if you have glaucoma or difficulty urinating due to prostate enlargement unless advised by your doctor.
  • DONT exceed the recommended dose.
  • DONT give to infants below 6 months of age.

8. Toxicology & Storage

Overdose: Symptoms are primarily due to Dicyclomine and reflect anticholinergic toxidrome: CNS effects (headache, dizziness, drowsiness, confusion, hallucinations, seizures, coma), cardiovascular effects (tachycardia, palpitations, hypotension, circulatory failure), blurred vision, dry mouth, difficulty swallowing, fever, hot dry skin, urinary retention, constipation, ileus, respiratory depression.

Storage: Store at room temperature (15-30°C). Protect from light and moisture. Keep the bottle tightly closed. Keep out of reach and sight of children. Do not freeze. Discard any unused suspension after the expiry date printed on the label. Do not store the measuring cup/spoon inside the bottle.