%0 Journal Article %T L-arginine, a nitric oxide precursor, reduces dapsone-induced methemoglobinemia in rats %A Moraes %A Nat¨˘lia Valadares de %A Bergamaschi %A Mateus Machado %A Bianchi %A Maria de Lourdes Pires %A Bragheto %A Juliana Bordinassi %A Malfar¨˘ %A Wilson Roberto %A Queiroz %A Regina Helena Costa %J Brazilian Journal of Pharmaceutical Sciences %D 2012 %I Universidade de S?o Paulo %R 10.1590/S1984-82502012000100010 %X dapsone use is frequently associated to hematological side effects such as methemoglobinemia and hemolytic anemia, which are related to n-hydroxylation mediated by the p450 enzyme system. the aim of the present study was to evaluate the influence of l-arginine supplementation, a precursor for the synthesis of nitric oxide, as single or multiple dose regimens on dapsone-induced methemoglobinemia. male wistar rats were treated with l-arginine at 5, 15, 30, 60 and 180 mg/kg doses (p.o., gavage) in single or multiple dose regimens 2 hours prior to dapsone administration (40 mg/kg, i.p.). the effect of the nitric oxide synthase inhibitor l-name was investigated by treatment with multiple doses of 30 mg/kg (p.o., gavage) 2 hours before dapsone administration. blood samples were collected 2 hours after dapsone administration. erythrocytic methemoglobin levels were assayed by spectrophotometry. the results showed that multiple dose supplementations with 5 and 15 mg/kg l-arginine reduced dapsone-induced methemoglobin levels. this effect is mediated by nitric oxide formation, since the reduction in methemoglobin levels by l-arginine is blocked by simultaneous administration with l-name, a nitric oxide synthase inhibitor. %K dapsone %K methemoglobinemia %K l-arginine %K nitric oxide %K l-name. %U http://www.scielo.br/scielo.php?script=sci_abstract&pid=S1984-82502012000100010&lng=en&nrm=iso&tlng=en