- Active Ingredient: Sildenafil citrate
- Appearance: Blue, film-coated, rounded-diamond-shaped tablets, typically debossed with “PFIZER” on one side and “VGR 100” or just “100” on the other.
- Mechanism: It works by increasing blood flow to the penis when a man is sexually stimulated, helping him get and maintain an erection.
- Dosage: The typical starting dose is 50 mg, but it can be increased to 100 mg or decreased to 25 mg based on effectiveness and side effects, as determined by a doctor. It should not be taken more than once a day.
- Timing: Take it orally about 30 minutes to 4 hours before sexual activity, with 1 hour prior being most effective. A high-fat meal may delay the onset of action.
- Efficacy Duration: The effects typically last for at least 4 hours, though they may be less after 2 hours.
Important Precautions and Warnings
- Prescription Only: Viagra is a prescription medication and should only be used under a doctor’s supervision.
- Drug Interactions: Do not take Viagra if you are also using nitrate drugs (often prescribed for chest pain), as this combination can cause a dangerous drop in blood pressure. Inform your doctor about all medications and supplements you are taking.
- Side Effects: Common side effects include headaches, flushing, stomach upset, and dizziness.
- When to Seek Immediate Medical Help:
- An erection that is painful or lasts longer than 4 hours (priapism).
- Sudden vision or hearing loss.
- Symptoms of a heart attack (chest pain, nausea, shortness of breath) during sexual activity.


