Certain medications, such as delavirdine, methadone, and fluticasone, can cause negative drug interactions with nelfinavir. These interactions can affect the drug levels in your blood, which could increase your risk for serious side effects or decrease the effectiveness of the medications. Other medicines that may cause negative nelfinavir interactions include oral contraceptives, ergot medications, erectile dysfunction medications, and other protease inhibitors.
Nelfinavir mesylate (Viracept®) can potentially interact with several other medicines. Some of these medicines that may lead to nelfinavir interactions include: