Men who are already taking medicines that contain nitrates, such as nitro-glycerine, are strongly advised not to use Viagra because the combination can lower blood pressure too much. There are also concerns about its safety following the deaths of a small number of American men who have taken the drug. The Food and Drug Administration is investigating. Some people in the UK are already taking Viagra. This allows the doctor to prescribe an unlicensed drug if they are satisfied that it is the right treatment and the patient takes full responsibility for anything that goes wrong.
Many men use vacuum devices or compression rings to get and keep an erection.
It is possible to have an injection in the base of the penis to increase the flow of blood. Surgery and implants are also an option in some cases. This page contains basic information. If you are concerned about your health, you should consult a doctor.