Do not take Viagra if you are taking any nitrate-based drug, including nitroglycerin patches (Nitro-Dur, Transderm-Nitro), nitroglycerin ointment (Nitro-Bid, Nitrol), nitroglycerin pills (Nitro-Bid, Nitrostat), and isosorbide pills (Dilatrate-SR, Isordil, Sorbitrate). Combining Viagra with these drugs can cause a severe drop in blood pressure.
If Viagra gives you an allergic reaction, do not use it again.
Side effects cannot be anticipated. If any develop or change in intensity, inform your doctor as soon as possible. Only your doctor can determine if it is safe for you to continue taking Viagra.
More common side effects may include:
Abnormal vision (color tinge, blurring, sensitivity to light), acid indigestion, diarrhea, flushing, headache, nasal congestion, urinary tract infection
Heart attack, stroke, heart irregularities, dangerous surges in blood pressure, and sudden death have all been reported after use of Viagra, usually in men with existing cardiac risk factors, and typically during or shortly after sex.
Taking Viagra approximately 1 hour before sexual activity works best for most men. Depending on how and when the drug works for you, an interval of one-half hour to as much as 4 hours may prove ideal.
–If you miss a dose…
Viagra is not for regular use. Take it only before sexual activity.
–Storage instructions…
Store at room temperature.