Caverta 50 Tablet (Sildenafil) is a prescription medicine for erectile dysfunction and may cause side effects such as headache, nausea, dizziness, indigestion, and stomach upset. VigRX Plus Tablet is a herbal supplement that helps stimulate sexual activity and maintain a firm erection, and may rarely cause mild stomach upset. Siteboost Tablet is a multivitamin that is generally well-tolerated, but may cause nausea or constipation.