Some mutations can keep multiplying even when you are taking an antiviral drug. When this happens, the drug will stop working. If you take a protease inhibitor by itself, resistance develops within one month. When you take more than one antiviral drug at the same time, HIV mutates much more slowly and it takes much longer for resistance to develop. Sometimes, if you develop resistance to one drug, you will also have resistance to other antiviral drugs.
Resistance can develop quickly.
It is very important to take protease inhibitors according to instructions, on schedule, and not to skip or reduce doses. The capsules are 200mg, so you will take 6 capsules every 8 hours. Researchers are studying twice a day dosing of saquinavir. Some physicians prescribe saquinavir in combination with another protease inhibitor, ritonavir. Studies are underway using a single daily dose of saquinavir taken with a small amount of ritonavir.