Dicyclomine + Domperidone + Simethicone

Usage

This combination medication is prescribed to alleviate symptoms associated with gastrointestinal disorders, particularly Irritable Bowel Syndrome (IBS). It addresses abdominal pain, cramping caused by intestinal spasms, bloating, and gas.

• Pharmacological Classification: This is a combination product containing an antispasmodic (dicyclomine), an antiemetic/prokinetic (domperidone), and an anti-foaming agent (simethicone).

• Mechanism of Action: Dicyclomine, an anticholinergic, blocks acetylcholine’s action, reducing gut muscle contractions and thus spasms and pain. Domperidone, a dopamine antagonist, enhances gut motility and speeds up gastric emptying, reducing bloating, nausea, and vomiting. Simethicone, an anti-foaming agent, diminishes the surface tension of gas bubbles, facilitating their coalescence and expulsion.

Alternate Names

This combination lacks a universally recognized International Nonproprietary Name (INN). It is often identified by its components: Dicyclomine + Domperidone + Simethicone. Brand names include Ranydol Spas. Regional brand names may differ.

How It Works

• Pharmacodynamics: Dicyclomine exerts anticholinergic effects, primarily on muscarinic receptors in the GI tract, inhibiting acetylcholine-mediated smooth muscle contractions. Domperidone antagonizes dopamine receptors, enhancing gastric motility and coordination. Simethicone decreases gas bubble surface tension, promoting coalescence for easier passage.

• Pharmacokinetics: Dicyclomine is well-absorbed orally and metabolized by the liver. Domperidone undergoes hepatic metabolism with limited systemic absorption. Simethicone is not absorbed systemically and is eliminated in the feces.

• Mode of Action: Dicyclomine’s action involves direct antimuscarinic activity at M1, M2, and M3 receptors and antagonism of bradykinin and histamine. Domperidone is a peripheral dopamine D2-receptor antagonist. Simethicone physically alters gas bubble surface tension.

• Elimination Pathways: Dicyclomine is primarily eliminated renally. Domperidone undergoes significant first-pass metabolism followed by hepatic and renal elimination. Simethicone is excreted unchanged in the feces.

Dosage

It’s important to note that the triple combination of dicyclomine, domperidone, and simethicone is not a standard clinical practice due to potential drug interactions, particularly between dicyclomine and domperidone, and the increased risk of adverse cardiac events with domperidone. Therefore, dosage information will be provided primarily for the more common combination of dicyclomine and simethicone.

Standard Dosage

Adults:

Dicyclomine + Simethicone: 20 mg dicyclomine/40 mg simethicone orally four times a day. This may be increased to 40 mg dicyclomine/40 mg simethicone four times a day if tolerated. The maximum daily dose for dicyclomine is 160 mg.

Children:

Infants (6-11 months): 5 mg dicyclomine/40 mg simethicone orally four times a day.

Children (2-12 years): Adjust dosage based on child’s weight and clinical response.

Special Cases:

Dosage adjustments should be made for patients with renal or hepatic impairment based on individual patient response and clinical status. Consider monitoring renal function in the elderly.

Clinical Use Cases

The use of this combination in clinical settings like intubation, surgical procedures, mechanical ventilation, ICU use, or emergency situations is not standard practice.

Dosage Adjustments

Adjustments based on renal/hepatic function, co-existing medical conditions, and patient response are essential.

Side Effects

Common Side Effects:

Dry mouth, blurred vision, dizziness, drowsiness, constipation, nausea, urinary retention.

Rare but Serious Side Effects:

Allergic reactions (rash, itching, swelling), confusion, hallucinations, cardiac arrhythmias (with domperidone).

Long-Term Effects:

Chronic complications from prolonged use are not well established, but potential anticholinergic effects with dicyclomine should be considered.

Adverse Drug Reactions (ADR):

Serious cardiac events, including QT prolongation and arrhythmias, are possible with domperidone and warrant immediate intervention.

Contraindications

Hypersensitivity to any component, GI obstruction, paralytic ileus, glaucoma, myasthenia gravis, QT prolongation risk (with domperidone). Infants under 6 months of age (dicyclomine).

Drug Interactions

Anticholinergics, antipsychotics, antihistamines, opioids, medications for Parkinson’s disease, other antispasmodics, potassium chloride, antidepressants (especially with domperidone). CYP450 interactions should be considered.

Pregnancy and Breastfeeding

Safety during pregnancy and breastfeeding is not well-established. Dicyclomine use is contraindicated in breastfeeding women. Consult a physician before use during pregnancy or lactation.

Drug Profile Summary

• Mechanism of Action: Antispasmodic, prokinetic, anti-foaming.
• Side Effects: Dry mouth, blurred vision, dizziness, drowsiness, constipation, nausea, urinary retention, cardiac arrhythmias (with domperidone).
• Contraindications: Hypersensitivity, GI obstruction, glaucoma, myasthenia gravis, QT prolongation risk (domperidone).
• Drug Interactions: Multiple, including anticholinergics, antipsychotics, and QT prolonging drugs.
• Pregnancy & Breastfeeding: Consult a physician; contraindicated during breastfeeding.
• Dosage: See Dosage section above (primarily for dicyclomine + simethicone combination).
• Monitoring Parameters: Heart rate, electrolyte levels (with domperidone), renal and hepatic function.

Popular Combinations

Due to the contraindication of combining dicyclomine and domperidone, this triple combination is not commonly used in clinical practice. Dicyclomine is frequently combined with simethicone.

Precautions

Pre-existing medical conditions (glaucoma, myasthenia gravis), age (infants, elderly), pregnancy and breastfeeding, potential for drowsiness and impaired driving.

FAQs (Frequently Asked Questions)

Q1: What is the recommended dosage for Dicyclomine + Simethicone?

A: Adults: 20 mg dicyclomine/40 mg simethicone four times a day, up to 40 mg/40 mg four times a day if tolerated. Infants (6-11 months): 5mg dicyclomine/40 mg simethicone four times a day. Children (2-12 years): Adjust dosage based on the child’s weight and clinical response.

Q2: Is the triple combination of Dicyclomine, Domperidone, and Simethicone commonly prescribed?

A: No, this triple combination is not typically used clinically due to potential drug interactions and cardiac risks associated with domperidone.

Q3: What are the key contraindications for Dicyclomine?

A: Glaucoma, myasthenia gravis, GI obstruction, urinary retention, and infants under six months of age.

Q4: What are the main concerns with Domperidone use?

A: Increased risk of serious cardiac events, including QT prolongation and arrhythmias.

Q5: What patient education should be provided regarding Dicyclomine + Simethicone?

A: Potential side effects like dry mouth, blurred vision, dizziness, and drowsiness. Caution patients about operating machinery or driving. Advise on potential drug interactions.

Q6: What are the alternatives to Domperidone for prokinetic action?

A: Metoclopramide may be considered, but careful evaluation of risk-benefit is crucial.

Q7: How should dosage be adjusted for patients with renal impairment?

A: Adjust dosage based on the degree of impairment and monitor renal function.

Q8: What is the mechanism of action of Simethicone?

A: Simethicone reduces the surface tension of gas bubbles in the GI tract, allowing them to coalesce for easier passage and reducing bloating.

Q9: Can Dicyclomine + Simethicone be used in pregnant women?

A: The safety of dicyclomine in pregnancy has not been adequately established. Use only if clearly needed and under medical supervision. Simethicone is generally considered safe during pregnancy.

Q10: What should be done in case of an overdose?

A: Seek immediate medical attention, particularly with the potential for cardiac events related to domperidone. Supportive care and symptomatic treatment may be required.