Zhewitra 40 mg may cause side effects in some individuals, including headache, flushing, dizziness, nasal congestion, and indigestion. Serious side effects such as sudden vision loss or hearing loss are rare but may occur. The usual recommended dose is one tablet taken orally, with or without food, about 30 minutes to 1 hour before sexual activity. The effects of Zhewitra typically last for about 4 to 5 hours.