With any medication, there are risks and benefits. Even if the medication is working, you may experience some unwanted side effects.
Contact your doctor immediately if you experience any of the following:
- Erection lasting for more than 4 hours
- Vision loss
- Hearing loss
The following side effects may get better over time as your body gets used to the medication. Let your doctor know immediately if you continue to experience these symptoms or if they worsen over time.
*Common side effects*
- Headache (11-15%)
- Indigestion (4-10%)
- Back pain (3-6%)
*Other side effects*
- Muslce ache (1-3%)
- Nasal congestion (2-3%)
- Flushing (2-3%)
- Pain in arms/legs (1-3%)
The following side effects have also been reported:
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:
*Less common*
Arm, back, or jaw pain, blurred vision, chest pain or discomfort, chest tightness or heaviness, chills, cold sweats, confusion, dizziness, fainting, faintness or lightheadedness when getting up suddenly from a lying or sitting position, fast or irregular heartbeat, headache, hearing loss, increased erection, nausea, nervousness, pain or discomfort in the arms, jaw, back, or neck, pounding in the ears, slow or fast heartbeat, spontaneous penile erection, sweating, unusual tiredness or weakness, vomiting
*Rare*
Painful or prolonged erection of the penis
*Incidence not known*
Blindness, blistering, peeling, or loosening of the skin, cough, cracks in the skin, decrease or change in vision, diarrhea, difficulty with speaking, double vision, fast, irregular, pounding, or racing heartbeat or pulse, headache, severe and throbbing, hives or welts, itching, skin rash, inability to move the arms, legs, or facial muscles, inability to speak, joint or muscle pain, loss of heat from the body, numbness or tingling of the face, hands, or feet, red skin lesions, often with a purple center, red, irritated eyes, red, swollen skin, redness of the skin, redness or soreness of the eyes, scaly skin, slow speech, sores, ulcers, or white spots in the mouth or on the lips, stomach pain, sudden cardiac death, swelling of the feet or lower legs
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:
*More common*
Belching, heartburn, indigestion, stomach discomfort, upset, or pain
*Less common*
Bloody nose, body aches or pain, burning, crawling, itching, numbness, prickling, "pins and needles", or tingling feelings, burning, dry, or itching eyes, burning feeling in the chest or stomach, congestion, difficulty with moving, difficulty with swallowing, dry mouth, dryness or soreness of the throat, excessive eye discharge, eye pain, feeling of constant movement of self or surroundings, feeling of warmth, redness of the face, neck, arms and occasionally, upper chest, fever, hoarseness, lack or loss of strength, loose stools, muscle aching or cramping, muscle stiffness, nasal congestion, neck pain, pain, pain in the arms or legs, pain or burning in the throat, redness, pain, swelling of the eye, eyelid, or inner lining of the eyelid, reduced sensitivity to touch, runny nose, sensation of spinning, sleepiness or unusual drowsiness, stomach upset, swelling of the eyelids, swelling or puffiness of the eyes or face, swollen joints, tearing, tender, swollen glands in the neck, tenderness in the stomach area, trouble with sleeping, upper abdominal or stomach pain, voice changes, watering of the eyes
*Rare*
Changes in color vision
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.