If you are a Mayo Clinic patient, this could include protected health information. Monitoring Parameters Monitor blood pressure and pulse when used concurrently with medications that lower blood pressure; monitor for pulmonary edema Pregnancy Pregnancy Considerations Sildenafil was shown to cross the placenta in an ex vivo placenta perfusion study Russo Please expect up to 4 to 6 weeks for reimbursement. Substantial consumption of ethanol may increase the risk of hypotension and orthostasis. Monitor therapy Clarithromycin: May increase the serum concentration of Sildenafil. Avoid combination Nefazodone: May increase the serum concentration of Sildenafil. · Sildenafil: 20 mg / 30 tablets. *Lowest online price at national pharmacy chains Costco, CVS, RiteAid, Walgreens and Walmart as of 1/19/ Prices vary by location and pharmacy, see test1.ru for actual pricing in your area. Visit test1.ru to find your nearest coupon prices.  · 10 tips to use sildenafil (aka Viagra) effectively. A set of instructions should be given to patients on sildenafil: A minimum wait of 45 minutes to 1 hour is required between taking the tablet. Sildenafil is a generic drug, which is an exact copy of the active drug in a brand-name medication. The generic is considered to be as safe and effective as the original drug. And generics tend to.