HIV/AIDS Glossary

Resistance to one or more drugs that occurs as a result of previous exposure to a similar drug. For example, HIV resistance to one non-nucleoside reverse transcriptase inhibitor (NNRTI) drug may produce resistance to all drugs in the NNRTI drug class, including drugs never used. Excluding all drugs in a drug class from an HIV regimen (class sparing) is a strategy used to prevent cross resistance.