What should I watch for?
Visit your doctor or health care professional for regular check ups. You will need lab work done before you start this medicine and regularly while you are taking it. Check your blood pressure as directed. Ask your health care professional what your blood pressure should be, and when you should contact him or her.
This medicine may make you feel dizzy or lightheaded. This is more likely to happen after the first dose, after an increase in dose, or during hot weather or exercise. Drinking alcohol and taking some medicines can make this worse. Do not drive, use machinery, or do anything that needs mental alertness until you know how this medicine affects you. Do not sit or stand up quickly. If you begin to feel dizzy, sit down until you feel better. These effects can decrease once your body adjusts to the medicine.
Contact your doctor or health care professional right away if you have an erection that 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 are thinking of having cataract surgery, tell your eye surgeon that you have taken this medicine.
Common and Rare Side Effects
Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.
Check with your doctor immediately if any of the following side effects occur:
Dizziness or lightheadedness
dizziness, faintness, or lightheadedness when getting up suddenly from a lying or sitting position
feeling of constant movement of self or surroundings
painful or prolonged erection of the penis
sensation of spinning
Incidence not known
Blistering, peeling, or loosening of the skin
difficult or labored breathing
fast, pounding, or irregular heartbeat or pulse
joint or muscle pain
large, hive-like swelling on the face, eyelids, lips, tongue, throat, hands, legs, feet, or sex organs
red skin lesions, often with a purple center
red, irritated eyes
sores, ulcers, or white spots in the mouth or on the lips
tightness of the chest
unusual tiredness or weakness
Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:
body aches or pain
lack or loss of strength
stuffy or runny nose
tender, swollen glands in the neck
Decreased interest in sexual intercourse
decreased sexual drive or performance
inability to have or keep an erection
loss in sexual ability, desire, drive, or performance
pain or tenderness around the eyes and cheekbones
sleepiness or unusual drowsiness
Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.
Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.