Usage
Colloidal bismuth subcitrate (CBS) is primarily prescribed for the treatment of peptic ulcers (gastric and duodenal ulcers) and Helicobacter pylori infections, often in combination with other medications as part of eradication therapy. It can also be used for gastritis associated with dyspepsia when H. pylori eradication is desired, and in the symptomatic treatment of mild, non-specific diarrhea, including traveler’s diarrhea and chronic infantile diarrhea. It is classified as an anti-ulcer drug and an antidiarrheal.
CBS works through several mechanisms. It inhibits the activity of pepsin and other proteolytic enzymes, stimulates the secretion of mucus and bicarbonate, thus enhancing mucosal defenses, and has direct antibacterial activity against H. pylori.
Alternate Names
Common alternate names include bismuth subcitrate, tripotassium dicitrato bismuthate, and bismuth tripotassium dicitrate. Brand names include De-Nol, Tritec (in combination with ranitidine), and Pylera (in combination with tetracycline and metronidazole).
How It Works
Pharmacodynamics: CBS acts locally in the gastrointestinal tract. It coats the ulcer crater, creating a protective barrier against gastric acid and pepsin. It also has bactericidal activity against H. pylori.
Pharmacokinetics: Orally administered CBS is minimally absorbed systemically. Bismuth is mainly excreted in feces. A small amount of absorbed bismuth can be excreted in urine.
Mode of Action: At a cellular level, CBS disrupts the cell wall of H. pylori, leading to bacterial cell death. Its protective effects are mediated by stimulating prostaglandin E2 synthesis and increasing bicarbonate and mucus secretion, leading to a strengthened mucosal barrier. CBS doesn’t exhibit any significant receptor binding, enzyme inhibition (apart from pepsin), or neurotransmitter modulation.
Elimination Pathways: Primarily eliminated through feces, with a small fraction excreted in the urine.
Dosage
Standard Dosage
Adults:
For peptic ulcers: 120 mg four times daily (one hour before meals and at bedtime) or 240 mg twice daily (one hour before meals) for 4-8 weeks. For H. pylori eradication, CBS is used in combination with other medications, and the dosage and duration depend on the specific regimen. One regimen involves 120 mg four times a day for 2 weeks.
Children:
The recommended dose is 10 mg/kg/day, divided into two doses, administered half an hour before meals. Use and dose should be determined by a doctor.
Special Cases:
- Elderly Patients: No specific dose adjustment is generally required. However, caution is advised due to potential age-related decline in renal function.
- Patients with Renal Impairment: Use with caution. In moderate to severe renal impairment, avoid use.
- Patients with Hepatic Dysfunction: No specific dose adjustment is generally required. Monitor liver function.
- Patients with Comorbid Conditions: Evaluate on a case-by-case basis.
Clinical Use Cases
The dosage of CBS in specialized settings like intubation, surgical procedures, mechanical ventilation, ICU use, or emergency situations is not specifically defined. Its use in these settings is not common.
Dosage Adjustments
Dosage adjustments are primarily necessary for patients with renal impairment.
Side Effects
Common Side Effects
Darkening of the stool and tongue, nausea, and mild constipation.
Rare but Serious Side Effects
Encephalopathy, neurotoxicity (especially with prolonged high doses).
Long-Term Effects
Long-term use of high doses may lead to bismuth accumulation and toxicity, particularly affecting the nervous system.
Adverse Drug Reactions (ADR)
Severe allergic reactions, though rare, require immediate attention.
Contraindications
Hypersensitivity to bismuth, history of gastrointestinal bleeding or coagulopathy, severe renal impairment. Pregnancy and breastfeeding require careful risk-benefit assessment. Use in children under 14 years of age is generally not recommended.
Drug Interactions
May decrease the absorption of tetracyclines, fluoroquinolones, and other drugs. Antacids, dairy products, and fruit juices can reduce the effectiveness of CBS.
Pregnancy and Breastfeeding
Pregnancy Safety Category: The FDA has not categorized CBS. Its use during pregnancy and breastfeeding should be avoided unless the potential benefits outweigh the risks to the fetus or infant.
Drug Profile Summary
- Mechanism of Action: Coats ulcer crater, inhibits pepsin, antibacterial against H. pylori.
- Side Effects: Dark stools, black tongue, nausea, constipation. Rarely: encephalopathy.
- Contraindications: Hypersensitivity to bismuth, GI bleeding, coagulopathy, severe renal impairment.
- Drug Interactions: Tetracyclines, fluoroquinolones, antacids.
- Pregnancy & Breastfeeding: Use with caution; avoid if possible.
- Dosage: Adults: 120 mg QID or 240 mg BID. Children: 10 mg/kg/day divided BID.
- Monitoring Parameters: Renal function, neurological status with prolonged use.
Popular Combinations
Commonly combined with antibiotics (e.g., metronidazole, tetracycline, clarithromycin) and proton pump inhibitors (e.g., omeprazole) for H. pylori eradication.
Precautions
Assess renal function. Monitor for neurologic symptoms with prolonged use. Caution in pregnancy and breastfeeding. Not generally recommended for children under 14.
FAQs (Frequently Asked Questions)
Q1: What is the recommended dosage for Colloidal bismuth subcitrate?
A: Adults: 120 mg QID or 240 mg BID. Children: 10 mg/kg/day BID. Dose adjustments needed for patients with renal impairment.
Q2: What is the role of Colloidal bismuth subcitrate in H. pylori eradication?
A: CBS has direct antibacterial activity against H. pylori and is used in combination therapies to eradicate the bacteria.
Q3: What are the most common side effects of Colloidal bismuth subcitrate?
A: Black stools and tongue, nausea, and constipation.
Q4: Can Colloidal bismuth subcitrate be used during pregnancy?
A: Use with caution during pregnancy and only if the benefits outweigh the risks.
Q5: How does Colloidal bismuth subcitrate work in treating peptic ulcers?
A: Forms a protective coating over the ulcer, inhibits pepsin, and promotes ulcer healing.
Q6: What are the contraindications for using Colloidal bismuth subcitrate?
A: Hypersensitivity to bismuth, severe renal impairment, history of GI bleeding.
Q7: Does Colloidal bismuth subcitrate interact with other medications?
A: Yes. It can interact with tetracyclines, fluoroquinolones, and antacids, potentially reducing their absorption.
Q8: How is Colloidal bismuth subcitrate eliminated from the body?
A: Primarily excreted in feces, with a small amount in urine.
Q9: What monitoring is needed for patients on long-term Colloidal bismuth subcitrate therapy?
A: Monitor renal function and neurological status periodically, especially with high doses.
