[Studies on the metabolism and distribution of 14C-sodium nitroprusside in rats (author's transl)].

Studies on the in vivo degradation of 14C-labelled nitroprusside (NP) were conducted in rats and indicated that the primary product was cyanide and not thiocyanate. With the administration of higher doses of sodium nitroprusside (NNP; Nipruss) cyanide, thipcyanate, Fe++ and Fe+++ were evident in the blood plasma, whereas [Fe(CN)6]4- and [Fe(CN)6]3- were not detected. The biological half-life for the disappearance of nitroprusside was about 2 min with a dose of 0.4 mg NNP/kg and was 28 min with a dose of 6.25 mg NNP/kg. Nitroprusside and its degradation products, cyanide and thiocyanate, were eliminated mainly in the urine. Significant accumulation of nitroprusside did not occur either in blood vessel walls, in smooth muscles, or in parenchymal organs.