Bismuth Subsalicylate / Metronidazole / Tetracycline Dosage
Applies to the following strength(s): 262.4 mg-250 mg-500 mg
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Usual Adult Dose for:
Additional dosage information:
Usual Adult Dose for Helicobacter pylori Infection
524.8 mg bismuth subsalicylate (chewable), metronidazole 250 mg, and tetracycline 500 mg orally four times daily for 14 days with meals and at bedtime. This therapy should be accompanied by a histamine-2 antagonist approved for the treatment of acute duodenal ulcer. The metronidazole tablet and the tetracycline capsule should be swallowed whole with a full glass of water (8 ounces).
Renal Dose Adjustments
Tetracycline is not recommended for use in patients with renal impairment (CrCl <50 mL/min). Tetracycline accumulates in patients with renal dysfunction and causes worsening of acidosis and elevated blood urea nitrogen (due to its catabolic effects). If a tetracycline is needed, doxycycline has a less pronounced catabolic effect and may therefore be preferable.
Liver Dose Adjustments
The use of aspirin in patients with severe hepatic impairment is not recommended due to the potential for increased risk of clinically significant bleeding and other adverse effects.
Patients with severe hepatic disease metabolize metronidazole slowly, with resultant accumulation of metronidazole and its metabolites in the plasma. Accordingly, for such patients, doses below those usually recommended should be administered cautiously. Close monitoring of plasma metronidazole levels and toxicity is recommended.
In patients where H pylori eradication is not accomplished following initial therapy, it is recommended that these patients be retreated with a regimen (plus the H2 antagonist) which does not contain metronidazole.
Bismuth subsalicylate/metronidazole/tetracycline is contraindicated in pregnant or nursing women, pediatric patients, in patients with renal or hepatic impairment. This product does not contain aspirin but should not be administered to those patients who have a known allergy to aspirin or salicylates.
Metronidazole should not be administered to patients who have taken disulfiram within the last two weeks.
Patients should be advised to avoid alcohol during metronidazole therapy and for at least 1 day after completion of therapy. Psychotic reactions have been reported in alcoholic patients who are using metronidazole and disulfiram concurrently.
Children and teenagers who are recovering from the flu or chicken pox should not receive bismuth subsalicylate to treat nausea or vomiting. If nausea or vomiting is present, patients should be advised to contact a doctor because this could be an early sign of Reye's syndrome, a rare but serious illness.
Neurotoxicity has been associated with excessive doses of bismuth subsalicylate. Symptoms resolved upon discontinuation of therapy.
Convulsive seizures and peripheral neuropathy (numbness or paresthesia of an extremity) have been reported in patients treated with metronidazole. The neuropathy was most prevalent in patients taking high doses for prolonged treatment periods.
Metronidazole should be discontinued if abnormal neurologic signs are present. Use caution if metronidazole is to be used in patients with central nervous system diseases.
Photosensitivity manifested by an exaggerated sunburn reaction has been observed in some individuals taking tetracyclines. Treatment should be discontinued at the first evidence of skin erythema.
Tetracyclines may cause an increase in blood urea nitrogen (BUN). In patients with significantly impaired renal function, higher serum levels of tetracycline may lead to azotemia, hyperphosphatemia, and acidosis.
Detailed information concerning the removal of aspirin by hemodialysis is not available. Some investigators have suggested that aspirin and/or salicylate may be removed by hemodialysis and that aspirin dosing should follow dialysis sessions. Metronidazole is dialyzable. Tetracycline is not dialyzable.
Upon oral administration, bismuth subsalicylate is almost completely hydrolyzed in the gastrointestinal tract to bismuth and salicylic acid. Each 262.4 mg tablet of bismuth subsalicylate (102 mg salicylate) contains approximately 130 mg aspirin.