Drug resistance: When HIV mutates (changes form), causing one or more anti-HIV medications to be ineffective.
Regimen: A combination of three or more anti-HIV medications from at least two different drug classes.
Treatment adherence: Closely following an HIV treatment regimen -- taking the correct dose of each anti-HIV medication at the correct time and exactly as prescribed.
Treatment adherence means following your treatment regimen closely every day -- taking the correct dose of each anti-HIV medication at the correct time and exactly as prescribed. Adherence is very important for successful HIV treatment.
Adherence affects HIV treatment in two ways:
Skipping medications makes it easier for drug resistance to develop. HIV can become resistant to the anti-HIV medications in a person's current regimen or to other, similar anti-HIV medications not yet taken, limiting options for successful HIV treatment. And drug-resistant strains of HIV can be transmitted to others, too.
There are many different anti-HIV medications and treatment regimens, but studies show that a person's first regimen offers the best chance for long-term treatment success. And good adherence from the start is key to successful treatment.
Adhering to an HIV treatment regimen can be difficult for several reasons. Some treatment regimens involve taking several pills every day -- with or without food, or before or after other medications. Other factors that can make treatment adherence difficult include:
Before you start treatment, be certain you're committed to taking anti-HIV medications every day as directed. Talk to your health care provider about any issues that can make adherence difficult, including:
Understanding issues that can make adherence difficult will help you and your health care provider select the best regimen for you. Some people find that adhering to an HIV treatment regimen becomes more difficult over time. So, every time you see your health care provider, make it a point to talk about adherence. (See the "Following an HIV Treatment Regimen" fact sheet for tips on adherence.)
Contact an AIDSinfo health information specialist at 1-800-448-0440 or visit http://aidsinfo.nih.gov. See your health care provider for medical advice.
This information is based on the U.S. Department of Health and Human Services' Guidelines for the Use of Antiretroviral Agents in HIV-1-Infected Adults and Adolescents.