Review article: safety of bismuth in the treatment of gastrointestinal diseases.

Bismuth preparations are commonly used to treat a variety of gastrointestinal disorders, including peptic ulcers and dyspepsia. The safety profile of currently approved bismuth preparations, such as tripotassium dicitrato bismuthate (De-Nol), bismuth subsalicylate (Pepto-Bismol) and ranitidine bismuth citrate (Pylorid, Tritec), is excellent. Adverse reactions to these agents are mild, transient and infrequent, and reports of serious adverse reactions are rare. This, in part, reflects the low systemic bioavailability of bismuth from these medicines: less than 1% of the bismuth dose administered is absorbed. During repeated dosing with ranitidine bismuth citrate 200, 400 or 800 mg b.d. trough plasma bismuth concentrations remain well below 50 micrograms/L. After 4 weeks of treatment median concentrations of 3.4 micrograms/L or less were reported amongst 1210 duodenal ulcer patients receiving this new chemical entity, while mean concentrations of 5.1 micrograms/L (plasma) and 12.3 micrograms/L (blood) have been reported in two studies of patients receiving tripotassium dicitrato bismuthate 120 mg q.d.s. for 4 weeks. Transient peak plasma bismuth concentrations greater than 50 micrograms/L are observed 30-60 min after dosing with tripotassium dicitrato bismuthate in some patients, but are not associated with any toxic effects. After discontinuation of treatment with bismuth preparations its excretion in urine may continue for up to 3 months, by which time blood bismuth concentrations have declined to pretreatment values.