if you have an allergic reaction to sildenafil or another a part of this drug. tell your medical doctor in case you are allergic to any capsules. make sure to inform about the allergy and what signs and symptoms you had. This consists of telling approximately rash; hives; itching; shortness of breath; wheezing; cough; swelling of face, lips, tongue, or throat; or some other symptoms. if you use pills known as poppers like amyl nitrite and butyl nitrite. if you have been informed no longer to have intercourse via your physician.