In addition to the high cost of prescription antifungals, they require that liver enzyme tests be performed to make sure they aren't adversely affected. Some physicians wants to take the tests before use, then perhaps once a month during use. I used Nizoral and Diflucan(not together) years ago, and imo the combination of grapefruit seed extract and olive leaf extract is much more potent, much safer than the prescription drugs, and much less expensive(especially when you factor in the cost of lab tests when using the prescription drugs).