
What should I watch for while using this medicine?
If you notice any changes in your vision while taking this drug, call your doctor or health care professional as soon as possible. Stop using this medicine and call your health care provider right away if you have a loss of sight in one or both eyes.
Contact you doctor or health care professional right away if the erection lasts longer than 4 hours or if it becomes painful. This may be a sign of serious problem and must be treated right away to prevent permanent damage.
If you experience symptoms of nausea, dizziness, chest pain or arm pain upon initiation of sexual activity after taking this medicine, you should refrain from further activity and call your doctor or health care professional as soon as possible.
Do not drink alcohol to excess (examples, 5 glasses of wine or 5 shots of whiskey) when taking this medicine. When taken in excess, alcohol can increase your chances of getting a headache or getting dizzy, increasing your heart rate or lowering your blood pressure.
Using this medicine does not protect you or your partner against HIV infection (the virus that causes AIDS) or other sexually transmitted diseases.
What side effects may I notice from this medicine?
Side effects that you should report to your doctor or health care professional as soon as possible:
allergic reactions like skin rash, itching or hives, swelling of the face, lips, or tongue
breathing problems
changes in hearing
chest pain
fast, irregular heartbeat
Side effects that usually do not require medical attention (report to your doctor or health care professional if they continue or are bothersome):
back pain
dizziness
flushing
headache
indigestion
muscle aches
stuffy or runny nose
This list may not describe all possible side effects.
