This effect was not seen in the study of 20 mg tadalafil taken for 6 months. Levitra tablets addition there was no adverse effect on mean concentrations of reproductive hormones, testosterone, luteinizing hormone or follicle stimulating hormone with either 10 or 20 mg of tadalafil compared to placebo. Dose-Response Relationship Dose-response relationships, between 20 mg and 40 mg, were not observed for 6-minute walk distance or pulmonary vascular resistance PVR in subjects with PAH in the placebo-controlled study. Over a dose Levitra pills of 2. In PAH patients administered between 20 and 40 mg of tadalafil, an approximately 1.