They need to know if you have any of these conditions:

Take this medicine by mouth with a glass of water. Follow the directions on the prescription label. The dose is usually taken 1 hour before sexual activity. You should not take the dose more than once per day. Do not take your medicine more often than directed.
Overdosage: If you think you have taken too much of this medicine contact a poison control center or emergency room at once.

This does not apply. Do not take double or extra doses.

Do not take this medicine with any of the following medications:

This medicine may also interact with the following medications:

This list may not describe all possible interactions. Give your health care provider a list of all the medicines, herbs, non-prescription drugs, or dietary supplements you use. Also tell them if you smoke, drink alcohol, or use illegal drugs. Some items may interact with your medicine.

If you notice any changes in your vision while taking this drug, call your doctor or health care professional as soon as possible. Call your health care provider right away if you have any change in vision. 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 a 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. Using this medicine does not protect you or your partner against HIV infection (the virus that causes AIDS) or other sexually transmitted diseases.

Side effects that you should report to your doctor or health care professional as soon as possible:

Side effects that usually do not require medical attention (report to your doctor or health care professional if they continue or are bothersome):

Keep out of reach of children.
Store at room temperature between 15 and 30 degrees C (59 and 86 degrees F). Throw away any unused medicine after the expiration date.