Patients should always ask their doctors for medical advice about adverse events. The body takes longer to absorb it after a high-fat meal or alcohol. Please expect up to 4 to 6 weeks for reimbursement. Its effects often last for 4 to 5 hours. In some patients, the use of VIAGRA with alpha-blockers can lead to a drop in blood pressure or to fainting medicines called HIV protease inhibitors, such as ritonavir Norvir , indinavir sulfate Crixivan , saquinavir Fortovase or Invirase , or atazanavir sulfate Reyataz some types of oral antifungal medicines, such as ketoconazole Nizoral and itraconazole Sporanox some types of antibiotics, such as clarithromycin Biaxin , telithromycin Ketek , or erythromycin other medicines that treat high blood pressure other medicines or treatments for ED VIAGRA contains sildenafil, which is the same medicine found in another drug called REVATIO. As with sildenafil, a high-fat meal or alcohol keep the body from absorbing it as quickly. Its effects might last longer if you have mild to moderate ED.The Savings Offer and Program expire on 12/31/ For further information, call , visit , or write: Viatris Inc., P.O. Box , Mission, KS . Currently, there are no over the counter alternatives to Viagra available. Viagra (sildenafil) is a prescription medication, meaning it’s not available over the counter from your local. Viagra is usually taken only when needed, 30 minutes to 1 hour before sexual activity. You may take it up to 4 hours before sexual activity. Other drugs may interact with .