Usage
Dicyclomine + Dimethicone is prescribed for the relief of symptoms associated with irritable bowel syndrome (IBS), such as abdominal pain, cramps, bloating, and flatulence. It is also used to treat other functional gastrointestinal disorders characterized by smooth muscle spasms and excessive gas.
Pharmacological Classification: This combination drug includes two components: Dicyclomine, an anticholinergic/antispasmodic, and Dimethicone, an anti-foaming agent.
Mechanism of Action: Dicyclomine inhibits the action of acetylcholine, a neurotransmitter that stimulates muscle contractions in the gut. This action reduces spasms and cramping. Dimethicone reduces the surface tension of gas bubbles trapped in the digestive tract, allowing them to coalesce and be expelled more easily, thus relieving bloating and flatulence.
Alternate Names
There is no officially recognized alternate name for the combination product Dicyclomine + Dimethicone itself, although the individual ingredients have other names. Dicyclomine hydrochloride is sometimes referred to simply as dicyclomine. Dimethicone is also known as simethicone or activated dimethicone.
Brand Names: This combination is available under various brand names, which can vary regionally. Examples include Colonext, Colimex, and Meftal-Spas. Many other formulations exist.
How It Works
Pharmacodynamics: Dicyclomine exerts its antispasmodic effect by competitively blocking muscarinic receptors, specifically M1 and M3 subtypes, located on smooth muscle cells in the gastrointestinal tract. This inhibition prevents acetylcholine from binding to these receptors and triggering muscle contractions, leading to decreased motility and spasm. Dimethicone works by decreasing the surface tension of gas bubbles in the GI lumen, facilitating their coalescence and expulsion.
Pharmacokinetics: Dicyclomine is well-absorbed orally and is metabolized primarily in the liver. It’s excreted mainly through the kidneys. Dimethicone is not absorbed systemically; it passes through the GI tract unchanged and is eliminated in the feces.
Mode of Action: Dicyclomine acts at the cellular level by interfering with muscarinic receptor activation on smooth muscle cells, ultimately preventing contraction. Dimethicone’s mode of action is physicochemical, altering the physical properties of gas bubbles rather than interacting with specific receptors or enzymes.
Receptor Binding/Enzyme Inhibition: Dicyclomine exhibits competitive antagonism at muscarinic receptors. Dimethicone does not involve receptor binding or enzyme inhibition.
Elimination Pathways: Dicyclomine is primarily eliminated via renal excretion following hepatic metabolism. Dimethicone is eliminated unchanged in the feces.
Dosage
The dosage of Dicyclomine + Dimethicone varies depending on the patient’s age, condition, and formulation of the medicine (drops, syrup, or tablets). It’s crucial to follow the prescribed dosage and instructions provided by the physician.
Standard Dosage
Adults:
The typical initial oral dose for adults is 20 mg of Dicyclomine + 40 mg of Dimethicone, taken four times a day. This can be increased to 40 mg of Dicyclomine + 40mg Dimethicone four times daily if needed and tolerated. For the injectable form (Dicyclomine only), 10-20 mg intramuscularly every 6 hours is the typical dose, not to exceed 80 mg/day IM. IV administration is not recommended.
Children:
Dosing for children varies by age and should be determined by a pediatrician. For infants older than 6 months, a common starting dose is 5 mg of Dicyclomine every 6-8 hours, not to exceed 20 mg/day. For older children, 10 mg of Dicyclomine every 6-8 hours, not exceeding 40 mg/day, might be prescribed. Some formulations combine Dicyclomine 10mg/ Simethicone 40mg per 5 ml of syrup, and pediatric doses are calculated based on this concentration.
Special Cases:
- Elderly Patients: Start with a lower dose due to the higher risk of anticholinergic side effects and potential for reduced renal function.
- Patients with Renal Impairment: Careful dose adjustment is advised.
- Patients with Hepatic Dysfunction: Dose reduction may be needed.
- Patients with Comorbid Conditions: Caution is advised in patients with cardiovascular disease, glaucoma, myasthenia gravis, urinary retention, and gastrointestinal obstruction.
Clinical Use Cases
Dicyclomine + Dimethicone is not typically used in clinical settings such as intubation, surgical procedures, mechanical ventilation, ICU care, or emergency situations. Its primary use is for managing symptoms of IBS and related gastrointestinal disorders in an outpatient setting.
Dosage Adjustments
Dose modification is based on individual patient responses and tolerance. Monitor for side effects and adjust accordingly. Consider renal and hepatic function when determining the appropriate dosage.
Side Effects
Common Side Effects:
Dry mouth, blurred vision, dizziness, drowsiness, constipation, nausea, and urinary retention.
Rare but Serious Side Effects:
Allergic reactions, rapid heart rate, confusion, hallucinations, difficulty breathing, and seizures.
Long-Term Effects:
Chronic use can lead to dependence on Dicyclomine. No specific long-term effects associated with Dimethicone are known.
Adverse Drug Reactions (ADR):
Anaphylaxis, paralytic ileus, and cardiac arrhythmias are potential ADRs.
Contraindications
Absolute contraindications include: hypersensitivity to dicyclomine or dimethicone, closed-angle glaucoma, myasthenia gravis, obstructive uropathy, paralytic ileus, gastrointestinal obstruction, unstable cardiovascular status in acute hemorrhage, toxic megacolon, severe ulcerative colitis, reflux esophagitis, and infants younger than six months of age. Breastfeeding is also generally contraindicated.
Drug Interactions
Dicyclomine can interact with other anticholinergic drugs, antidepressants (especially tricyclic antidepressants), antihistamines, antipsychotics, and some pain medications, potentially enhancing anticholinergic side effects. It can also interact with certain medications for heart problems (e.g., digoxin), asthma (e.g., ipratropium), and other irritable bowel medications. Alcohol should be avoided as it can increase drowsiness and other side effects.
Pregnancy and Breastfeeding
Dicyclomine is classified as Pregnancy Category B. It should be used during pregnancy only if clearly needed. Dicyclomine is contraindicated during breastfeeding as it can be excreted in breast milk and may cause side effects in infants. Simethicone is generally considered safe during both pregnancy and breastfeeding.
Drug Profile Summary
- Mechanism of Action: Dicyclomine: Anticholinergic, inhibiting gut motility; Dimethicone: Anti-foaming, reducing gas bubbles.
- Side Effects: Dry mouth, blurred vision, dizziness, drowsiness, constipation.
- Contraindications: Glaucoma, myasthenia gravis, GI obstruction, urinary retention, infants under 6 months.
- Drug Interactions: Anticholinergics, antidepressants, antihistamines.
- Pregnancy & Breastfeeding: Use with caution in pregnancy; contraindicated in breastfeeding.
- Dosage: Adults: Initially 20 mg four times daily, may increase to 40 mg four times daily. Pediatric doses vary.
- Monitoring Parameters: Heart rate, blood pressure, bowel sounds, signs of anticholinergic toxicity.
Popular Combinations
Dicyclomine is sometimes combined with other medications to manage specific symptoms, such as analgesics for pain relief. Combining dicyclomine and dimethicone addresses both spasm and gas.
Precautions
- General Precautions: Evaluate patients for underlying medical conditions, including glaucoma, urinary retention, and cardiovascular disease.
- Specific Populations: Use with caution in pregnant women, contraindicated in breastfeeding women and infants under 6 months. Dose adjustment may be needed in older adults.
FAQs (Frequently Asked Questions)
Q1: What is the recommended dosage for Dicyclomine + Dimethicone?
A: The adult dosage is typically 20 mg Dicyclomine/40 mg Dimethicone four times daily, potentially increasing to 40 mg Dicyclomine four times a day. Pediatric and elderly patients require adjusted dosing determined by a physician.
Q2: What are the common side effects?
A: Common side effects include dry mouth, blurred vision, dizziness, constipation, drowsiness, nausea, and urinary retention.
Q3: Is Dicyclomine + Dimethicone safe during pregnancy?
A: Dicyclomine should only be used during pregnancy if clearly needed due to potential risks. Consult an obstetrician for guidance. Simethicone is considered safe.
Q4: Can I take this medication while breastfeeding?
A: Dicyclomine is contraindicated during breastfeeding due to its presence in breast milk. Simethicone is generally considered safe.
Q5: How does Dicyclomine + Dimethicone work in IBS?
A: Dicyclomine reduces bowel spasms, while dimethicone relieves bloating and gas, thus addressing multiple IBS symptoms.
Q6: Are there any drug interactions I should be aware of?
A: Yes, Dicyclomine can interact with other anticholinergics, antidepressants, antihistamines, and some heart medications. Inform your physician of all other medications you’re taking.
Q7: What should I do if I miss a dose?
A: Take the missed dose as soon as you remember. However, if it’s close to your next scheduled dose, skip the missed dose and return to your regular schedule. Do not double the dose.
Q8: Can I operate machinery while taking this medication?
A: Use caution as dicyclomine can cause drowsiness or blurred vision, which may impair your ability to operate machinery safely.
Q9: What are the signs of an allergic reaction to this drug?
A: Signs of an allergic reaction can include skin rash, itching, swelling (especially of the face, tongue, or throat), severe dizziness, and difficulty breathing. Seek immediate medical attention if these occur.
Q10: How long does it take for Dicyclomine + Dimethicone to work?
A: The onset of action can vary, but many people experience some relief within 30-60 minutes of taking the medication.
