Along with its needed effects, sildenafil (the active ingredient contained in Viagra) 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 while taking sildenafil:
Less common
- Bladder pain
- burning feeling in the chest or stomach
- burning, crawling, itching, numbness, prickling, “pins and needles”, or tingling feelings
- cloudy or bloody urine
- dizziness
- increased frequency of urination
- indigestion
- pain on urination
- stomach upset
- tenderness in the stomach area
Rare
- Abnormal vision
- anxiety
- behavior change similar to drunkenness
- bleeding of the eye
- blurred vision
- bone pain
- breast enlargement
- chest pain
- chills
- cold sweats
- confusion
- convulsions (seizures)
- cool and pale skin
- deafness or hearing loss
- decrease in amount of urine or the frequency of urination
- decreased vision
- difficulty in concentrating
- dizziness or lightheadedness, especially when getting up suddenly from a lying or sitting position
- double vision
- drowsiness
- dry eyes
- dry mouth
- dryness, redness, scaling, or peeling of the skin
- excessive hunger
- eye pain
- fainting or faintness
- fast, irregular, or pounding heartbeat
- feeling of something in the eye
- fever or chills
- headache (severe or continuing)
- increase in the size of the pupil
- increased sweating
- increased thirst
- lower back or side pain
- migraine headache
- nausea (severe or continuing)
- nervousness
- nightmares
- numbness of the hands
- painful, swollen joints
- prolonged, painful erection of penis
- redness, burning, or swelling of the eyes
- redness, itching, or tearing of the eyes
- restless sleep
- seeing shades of colors differently than before
- sensitivity to light
- shakiness
- skin lesions with swelling
- skin paleness
- skin rash, hives, or itching
- skin ulcers
- slurred speech
- sore throat
- sudden weakness
- swelling of the face, hands, feet, or lower legs
- trouble breathing
- twitching of the muscles
- unusual feeling of burning or stinging of the skin
- unusual tiredness or weakness
- vision changes
- vision loss, temporary
Incidence not known
- Blindness
Side effects not requiring immediate medical attention
Some side effects of sildenafil 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
- Aches or pains in the muscles
- bloody nose
- diarrhea
- difficult or labored breathing
- flushing
- headache
- pain or tenderness around the eyes and cheekbones
- redness of the skin
- sneezing
- stomach discomfort following meals
- stuffy or runny nose
- trouble sleeping
- unusually warm skin
Rare
- Abdominal or stomach pain
- abnormal dreams
- anxiety
- 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 the hands, legs, or feet
- rectal bleeding
- redness or irritation of the tongue
- redness, soreness, swelling, or bleeding of the gums
- ringing or buzzing in the 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 the mouth and on the lips
- tense muscles
- trembling and shaking
- vomiting
- waking to urinate at night
- worsening of asthma