Bismuth subnitrate absorption

In rats, the effects of various thiol compounds (mercaptopropionic acid, D-penicil-lamine, Ucysteine, DL-homocysteine, 2-mercaptoethylamine and mercaptoethane) on the absorption and elimination of bismuth subnitrate given orally were determined. All of the thiol substances, and particularly cysteine, homocysteine and mercaptopropionic acid, enhanced Bi absorption and elimination. Moreover, the acute toxicity of Bi was enhanced when Bi was given as a complex with cysteine (LDjq = 156mgkg ). Studies of and N NMR confirmed complexation of Bi and cysteine. The enhancement of the absorption, elimination and acute toxicity of Bi may be caused by the increases of solubility and permeability of Bi arising from complexation with thiol compounds. 

Nwokolo CU, Prewett EJ, Sawyer AA, et al. Lack of bismuth absorption from bismuth subnitrate (Roter) tablets. Eur J Gastroenterol Hepatol 1989 5 433. 

Ranitidine possibly causes an increase in the absorption of bismuth from tripotassium dicitratobismuthate, but not bismuth salicylate or bismuth subnitrate. Any increase is considered unlikely to be clinically relevant with recommended short courses for H. pylori eradication. Other H2-receptor antagonists would be expected to interact similarly. 

The AUC of a single 240-mg dose of tripotassium dicitratobismuthate (TDB, De Noltabs), was increased fourfold in 12 healthy subjects given two 300-mg doses of ranitidine (one the night before and one 2 hours before the bismuth compound). The maximum serum levels were approximately doubled. The same regimen of ranitidine had no significant effect on the absorption of bismuth from bismuth salicylate (Pepto-Bismol) or bismuth subnitrate (Roter tablets) ... 

RANITIDINE TRIPOTASSIUM DICITRATOBISMUTHATE t adverse effects of tripotassium dicitratobismuthate t absorption Do not use together for more than 16 weeks. Bismuth salicylate and subnitrate do not interact... 

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