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.