Usage
Dicyclomine + Ranitidine is prescribed for the relief of abdominal pain and discomfort associated with gastrointestinal disorders, such as irritable bowel syndrome (IBS), gastroesophageal reflux disease (GERD), peptic ulcers, and functional dyspepsia.
Pharmacological Classification:
- Dicyclomine: Anticholinergic/antispasmodic
- Ranitidine: H2 receptor antagonist
Mechanism of Action: This combination medication works through two distinct mechanisms:
- Dicyclomine relaxes the smooth muscles of the gastrointestinal tract, reducing spasms and cramps. It achieves this by blocking the action of acetylcholine, a neurotransmitter responsible for muscle contraction.
- Ranitidine decreases the production of stomach acid by blocking histamine H2 receptors in the stomach lining. This helps to relieve heartburn, acid reflux, and promotes the healing of ulcers.
Alternate Names
There are no widely recognized alternate names for the combination product itself. However, the individual components are known by their generic names (dicyclomine hydrochloride and ranitidine) and various brand names.
Brand Names: A commonly marketed brand name for this drug combination was Zanocin. However, this is no longer available as ranitidine has been withdrawn from the market in many countries due to safety concerns.
How It Works
Pharmacodynamics:
- Dicyclomine: Relaxes smooth muscle in the GI tract by blocking the action of acetylcholine at muscarinic receptors.
- Ranitidine: Reduces gastric acid secretion by blocking histamine H2 receptors on parietal cells.
Pharmacokinetics:
- Dicyclomine: Well absorbed orally. Metabolized primarily in the liver and excreted mainly in urine.
- Ranitidine: Absorbed rapidly after oral administration. Undergoes some hepatic metabolism but primarily excreted unchanged in the urine.
Mode of Action:
- Dicyclomine acts as a competitive antagonist at muscarinic receptors, preventing acetylcholine from binding and triggering muscle contraction.
- Ranitidine competitively inhibits the binding of histamine to H2 receptors on parietal cells, reducing the activation of adenylate cyclase and consequently, gastric acid secretion.
Elimination Pathways:
- Dicyclomine: Primarily hepatic metabolism, with subsequent renal excretion.
- Ranitidine: Primarily renal excretion, with some hepatic metabolism.
Dosage
Due to ranitidine’s withdrawal from the market in numerous locations including the US and India, dosing information for the combination product Dicyclomine + Ranitidine is not available as this combination is no longer marketed or prescribed. The dosage information below reflects how each drug was dosed when they were available:
Dicyclomine
Standard Dosage
Adults:
- Initial: 20 mg orally four times a day.
- Maintenance: Up to 40 mg orally four times a day (after one week on initial dose).
Children:
- Not recommended for children under 18 years of age. Contraindicated in infants under 6 months.
Special Cases:
- Elderly: Use with caution due to increased risk of adverse effects.
Ranitidine
Standard Dosage
Adults:
Dosages varied depending on the indication but often involved 150 mg twice daily or 300 mg at bedtime.
Children:
Dosages were weight-based.
Special Cases:
Dose adjustments were necessary for patients with renal impairment.
Side Effects
Common Side Effects:
- Dry mouth, constipation, blurred vision, drowsiness, dizziness, headache, weakness, and nausea.
Rare but Serious Side Effects:
- Confusion, hallucinations, difficulty urinating, rapid heart rate, and allergic reactions.
Contraindications
- Hypersensitivity to either dicyclomine or ranitidine.
- Glaucoma, urinary retention, obstructive gastrointestinal disorders, myasthenia gravis, severe ulcerative colitis, and toxic megacolon.
Drug Interactions
- Other anticholinergic medications, antacids, some antidepressants, some antipsychotics, and alcohol can interact with dicyclomine, increasing the risk of side effects.
Pregnancy and Breastfeeding
- Dicyclomine + Ranitidine’s use during pregnancy and breastfeeding is generally discouraged due to potential risks to the fetus or infant.
Drug Profile Summary
The Dicyclomine + Ranitidine combination is no longer available. Information here describes the properties when this medication was available.
- Mechanism of Action: Dicyclomine: Anticholinergic/antispasmodic, relaxing smooth muscles. Ranitidine: H2 receptor antagonist, reducing stomach acid.
- Side Effects: Dry mouth, constipation, blurred vision, drowsiness, dizziness. Serious: Confusion, hallucinations, urinary retention.
- Contraindications: Hypersensitivity, glaucoma, urinary retention, GI obstructions.
- Drug Interactions: Anticholinergics, antacids, some antidepressants, alcohol.
- Pregnancy & Breastfeeding: Use with caution; potential fetal/infant risks.
Popular Combinations
This combination is no longer marketed.
Precautions
- Caution in elderly patients and those with cardiovascular disease, hyperthyroidism, liver or kidney impairment.
FAQs (Frequently Asked Questions)
Q1: What conditions was Dicyclomine + Ranitidine used to treat?
A: This combination, no longer available, was previously prescribed for conditions like IBS, GERD, peptic ulcers, and functional dyspepsia.
Q2: Why is Dicyclomine + Ranitidine no longer available?
A: Ranitidine, a component of this combination, was withdrawn from the market due to safety concerns related to the presence of N-nitrosodimethylamine (NDMA), a potential carcinogen.
Q3: What are the common side effects of this combination?
A: Side effects could include dry mouth, constipation, blurred vision, drowsiness, dizziness, and headache.
Q4: Are there any medications that should not be taken with this combination?
A: Yes, other anticholinergics, some antidepressants and antipsychotics, as well as alcohol should be avoided or used with caution as they may enhance the side effects.
Q5: Can this combination product be used during pregnancy or breastfeeding?
A: Dicyclomine + Ranitidine was generally not recommended during pregnancy or while breastfeeding due to potential risks to the baby. Safer alternatives should be considered.
Q6: What was the typical adult dose of Dicyclomine + Ranitidine?
A: Dosing recommendations would vary depending on the indication and could change over time based on the patient’s response. A medical professional would need to determine the appropriate dose. As this medication is no longer available, this is not applicable anymore.
Q7: What should patients do if they are currently taking a medication containing ranitidine?
A: Patients taking any ranitidine-containing product should speak with their doctor about discontinuing its use and switching to a safer alternative.
Q8: What are the alternatives for managing conditions previously treated with Dicyclomine + Ranitidine?
A: Treatment options may include other antispasmodics, H2 receptor antagonists (other than ranitidine), proton pump inhibitors, and lifestyle modifications depending on the specific condition being addressed. A medical professional should determine the appropriate treatment.
Q9: Are there any drug interactions to be aware of with the individual components?
A: Yes, dicyclomine may interact with other anticholinergic medications, enhancing their effects. Ranitidine may affect the absorption of certain drugs, and also has interactions with antacids. It is critical to disclose all medications being taken to a physician to avoid adverse events.
