A very serious allergic reaction to this drug is rare.
However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.
Be sure to tell your doctor and pharmacist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).
Tell your doctor if your condition does not improve.
Before taking sildenafil, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies.
This product may contain inactive ingredients, which can cause allergic reactions or other problems. Before using this medication, tell your doctor or pharmacist your medical history, especially of: heart problems (such as heart attack or life-threatening irregular heartbeat in the past 6 months, chest pain/angina, heart failure), stroke in the past 6 months, kidney disease, liver disease, high or low blood pressure, a severe loss of body water (dehydration), penis conditions (such as angulation, fibrosis/scarring, Peyronie's disease), history of painful/prolonged erection (priapism), conditions that may increase the risk of priapism (such as sickle cell anemia, leukemia, multiple myeloma), eye problems (such as retinitis pigmentosa, sudden decreased vision, NAION). Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).
Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects.
The dosage is based on your medical condition, response to treatment, and other medications you may be taking.Stop taking sildenafil and get medical help right away if these effects occur.In the rare event you have a painful or prolonged erection lasting 4 or more hours, stop using this drug and get medical help right away, or permanent problems could occur.Sildenafil is used to treat male sexual function problems (impotence or erectile dysfunction-ED).In combination with sexual stimulation, sildenafil works by increasing blood flow to the penis to help a man get and keep an erection.