PDE5 inhibitors are a class of medications that includes silagra. It functions by causing your penis' blood vessels to relax. When a person is sexually stimulated, this permits blood to enter the penis and cause an erection. Men should consult a doctor before using any other medications to treat impotence, as silagra is not meant for use by women. If you have low blood pressure, recently had a heart attack or stroke, or have serious heart or liver problems, do not use this medication. You can take Silagra with or without food, although taking it at a set time is recommended.  Follow your doctor's instructions on the dosage and duration of this medication.