Zenegra 100 mg should not be used with nitrates or certain heart medicines because it can dangerously lower blood pressure. It should also be used carefully in people with heart disease, low blood pressure, liver or kidney problems, or a recent stroke or heart attack. Alcohol may increase side effects and reduce effectiveness. Common side effects include headache, flushing, dizziness, blurred vision, stomach upset, muscle pain, and nasal congestion. Some people may also notice rash, indigestion, or sleepiness.

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