People taking nitrates like nitroglycerin Nitrostat or isosorbide mononitrate Imdur should not take PDE5 inhibitors, as doing so could result in a dangerous drop in blood pressure. Sudden vision loss in one or both eyes can be a sign of a serious eye problem called non-arteritic anterior ischemic optic neuropathy NAION. This information is reviewed by a licensed practitioner who will assess your eligibility for the medication. Box , Mission, KS If your pharmacy does not participate, you may be able to submit a request for a rebate in connection with this Savings Offer. You’ll also need to fill out a medical questionnaire with answers about your medical history, current medications, and lifestyle habits. If you prefer, you may contact the U.Side Effects. Dizziness, headache, flushing, or stomach upset may occur. Vision changes such as increased sensitivity to light, blurred vision, or trouble telling blue and green colors apart may.  · Sildenafil is used to treat men who have erectile dysfunction (also called sexual impotence). Sildenafil belongs to a group of medicines called phosphodiesterase 5 (PDE5) inhibitors. These medicines prevent an enzyme called phosphodiesterase type-5 from working too quickly. The penis is one of the areas where this enzyme works. The products on this page have been transferred to VIATRIS SPECIALTY LLC. The U.S. Physician Prescribing Information and Patient Information on this page may no longer be current. Please visit for the most current product information. for Consumers: VIAGRA en Español. for Healthcare professionals: VIAGRA U.S.