Consequently, the patient must take increased drug concentrations to prevent replication, IC100. As a result, the viral load increases. Therefore, treatment recommendations should be tailored to an individuals's assessment of their ability to manage different dosing schedules and dietary requirements for the different drugs. Resistance HIV infection is characterized by high rates of viral replication, resulting in a high frequency of viral mutations and different strains. The mutation rate in HIV is high because the enzyme responsible for copying the genetic code makes many errors.
Resistance can develop against all anti-HIV drugs and drugs to treat opportunistic infections.
The virus becomes resistant by acquiring a mutation that desensitizes it to drug action, but does not damage itself. However, before treatment is started, the mutant or resistant strains are less frequent and the natural strain predominates as it replicates more efficiently. This strain is better suited to its environment. When a drug modifies the environment, one of the less frequent HIV strains multiply while the dominant strain is inhibited. The virus must acquire multiple mutations to overcome the action of two or more drugs simultaneously and this is highly unlikely to occur.