Sildenafil oral jelly 100 mg kamagra is a member of the class of drugs known as PDE5 inhibitors. 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. If you also take any nitrate-containing medications, avoid using this one. The recommended amount of time to wait before having sex is one hour. Work takes different amounts of time for different people, but it often takes 30 to 1 hour. Men should not use this medication or any other medication to treat impotence without first consulting a physician. It is not meant for use by women.