Drug resistance happens when HIV mutates, or changes itself, so that the HIV medicines a person is taking are no longer effective. People who become resistant to one drug may also become resistant to other drugs, including drugs they have never taken. Tests are available to help find out whether a person is resistant to any HIV medicine.
Drug resistance is much less likely to develop if the amount of HIV in a person’s body is kept as low as possible. That is why it is important that people with HIV take their HIV medicines as prescribed and not skip doses. Case managers, adherence counselors, and treatment educators can help people with HIV figure out strategies for taking their HIV medicines successfully.