VIAGRA has sildenafil, which is identical medicine present in another drug named REVATIO. REVATIO is employed to treat a exceptional disease identified as pulmonary arterial hypertension (PAH).Thu?c Kamagra 50mg hay Kamagra 100mg ch?a ho?t ch?t sildenafil theo hàm l??ng t??ng ?ng, thu?c nhóm thu?c ???c g?i là ch?t ?c ch? phosphodiesterase lo?i f