Comparative effects of quinacrine and erythromycin in adult female rats : a nonsurgical sterilization study

Abstract Objective: To compare the efficacies of erythromycin and quinacrine for nonsurgical sterilization in rats. Quinacrine used for nonsurgical sterilization in women is mutagenic, and most clinical regimens have had a higher failure rate than surgical sterilization. Design: This acute mammal study included five groups of rats assigned randomly and evaluated at two times after treatment. Animal(s): Adult female Sprague-Dawley rats. Intervention(s): Five groups of female Sprague-Dawley rats (20 per group) were given 70 or 280 mg/kg of erythromycin lactobionate, 350 mg/kg of quinacrine hydrochloride, or vehicle control administered transcervically. Rats were mated 21 days later. Additional groups (n = 4 per group) were treated and killed 21 days later without mating. Main Outcome Measure(s): Fourteen days after mating, numbers of ovarian corpora lutea, total uterine implants, and embryos were evaluated. For unmated animals, uterine sections were examined for fibrosis and lumen closure. Result(s): Neither drug altered numbers of corpora lutea. Erythromycin decreased pregnancy rate and number of implantations (increased preimplantation loss) in a dose-related fashion. Quinacrine increased resorptions. Uterine pathology was more extensive and frequent in erythromycin-treated animals, with extent and severity increasing from 21 to 35+ days. Conclusion(s): Erythromycin was more effective than quinacrine in preventing pregnancy.