Side Effects of This Medicine

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.

Less common

Abnormal vision, including blurred vision, seeing shades of colors differently than before, or sensitivity to light; bladder pain; cloudy or bloody urine; dizziness; increased frequency of urination; pain on urination

Rare

Bleeding of the eye; convulsions (seizures); decreased vision or other changes in vision; double vision; prolonged, painful, or inappropriate erection of penis; redness, burning, or swelling of the eye; vision loss, temporary

Note: The following rare side effects have not been completely established as being caused by sildenafil

Blood sugar problems (more likely with patients with diabetes mellitus), such as anxiety, behavior change similar to drunkenness, blurred vision, cold sweats, confusion, cool and pale skin, difficulty in concentrating, drowsiness, excessive hunger, fast heartbeat, headache, nausea, nervousness, nightmares, restless sleep, shakiness, slurred speech, and unusual tiredness or weakness; bone pain; breast enlargement; chest pain; chills; confusion; convulsions (seizures); deafness; decrease in amount of urine or in frequency of urination; dizziness or lightheadedness, especially when getting up from a lying or sitting position; dry eyes; dry mouth; dryness, redness, scaling, or peeling of the skin; eye pain; fainting or faintness; fast, irregular, or pounding heartbeat; feeling of something in the eye; groups of skin lesions with swelling; headache (severe or continuing); heart failure; hives; increase in size of pupil; increased sweating; increased thirst; itching of skin; low blood pressure; lower back or side pain; migraine headache; nausea (severe or continuing); nervousness; numbness of hands; painful, swollen joints; redness, itching, or tearing of eyes; shortness of breath or troubled breathing; skin paleness; skin rash; skin ulcers; sore throat and fever or chills; sudden weakness; swelling of face, hands, feet, or lower legs; twitching of muscles; unusual tiredness or weakness; unusual feeling of burning or stinging of skin

Other 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. However, check with your doctor if any of the following side effects continue or are bothersome:

More common

Flushing; headache; nasal congestion; stomach discomfort following meals

Less common

Diarrhea

Rare

Anxiety

Note: The following rare side effects have not been completely established as being caused by sildenafil

Abdominal pain; abnormal dreams; aches or pains of muscles; clumsiness or unsteadiness; cough; diarrhea or stomach cramps (severe or continuing); difficulty in swallowing; ear pain; increased amount of saliva; increased skin sensitivity; lack of coordination; loss of bladder control; mental depression; nausea; numbness or tingling of hands, legs, or feet; rectal bleeding; redness or irritation of the tongue; redness, soreness, swelling, or bleeding of gums; ringing or buzzing in ears; sensation of motion, usually whirling, either of one's self or of one's surroundings; sexual problems in men (continuing), including failure to experience a sexual orgasm; sleepiness; sores in mouth and on lips; tense muscles; tightness of chest or wheezing; trembling and shaking; trouble in sleeping; vomiting; waking to urinate at night; worsening of asthma

Other side effects not listed above may also occur in some patients. If you notice any other effects, check with your doctor.