Invirase is a brand name for the drug saquinavir, which is used to treat HIV/AIDS. Synonyms for this drug include Fortovase, saquinavir mesylate, and SQV. Fortovase is a newer version of saquinavir that has been improved for better absorption in the body. Saquinavir mesylate is the active ingredient in both Invirase and Fortovase. SQV is the abbreviation for saquinavir and is sometimes used in medical shorthand. It is important to note that while these synonyms refer to the same drug, they may have different dosages, formulations, or methods of administration. It is important to follow the instructions given by your healthcare provider for the specific medication prescribed.