The most common Unwanted effects of VIAGRA: headache; flushing; upset stomach; abnormal vision, including changes in coloration eyesight (for example possessing a blue color tinge) and blurred eyesight; stuffy or runny nose; again agony; muscle mass agony; nausea; dizziness; rash.Grapefruit juice: Grapefruit juice may well interfere with the absorp