Sildenafil generic Suhagra 25 mg is a phosphodiesterase type 5 (PDE5) inhibitor, prescribed for erectile dysfunction (impotence). Erectile dysfunction is the inability to achieve or maintain an erection long enough to perform intercourse. It relaxes the blood vessels in the penis, allowing more blood to enter to achieve an erection. It can also be used in pulmonary arterial hypertension.