Effects of pyrazinamide on pregnant albino rats

RESUMO

Although being used for years in the treatment of tuberculosis, no data are available in the literature on the safety of pyrazinamide during pregnancy. Accordingly, we aimed to make a first approach to this problem by evaluating the effects of this drug administered during the entire pregnancy of albino rats. Fourty female, EPM-1 Wistar albino rats of about 250 g b.w. were used. Upon conception (day zero of pregnancy) the animals were randomly divided in 4 groups of 10 rats each and labeled as follows. Controls (C), animals treated with the drug vehicle (destilled water); experimental groups (E1, E2 and E3), animals treated with 35, 105 or 315 mg/kg b.w. pyrazinamide by gavage (oral route) once daily up to the term (20th day of pregnancy). Drug or vehicle volume was always 0.5 ml. Body weight gain was followed up every week. At term, upon sacrifice (in excess of anesthesia) and histerectomy, the following parameters have been studied number of implantations and reabsorptions; intrauterine deaths; number of living foetuses and of placentae; weights of concepts and of placentae; major foetal malformations; maternal mortality index. No significant effects of pyrazinamide on rat pregnancy have been observed regarding the maternal body weight gain, the weights of concepts, the number of implantations and reabsorptions and the weights of placentae and foetuses. Also, no deleterious effects have been noticed regarding major foetal malformations, intrauterine deaths or maternal mortality. With the highest pyrazinamide dosis employed (315 mg/kg b.w.), however, a significant lowered uterine weight was recorded. Although otherwise safe, a high-dose regimen of pyrazinamide during rat pregnancy can induce a slight yet significant reduction of uterine weight.