(Last updated 5/6/2014; last reviewed 5/6/2014)
Adherence means “to stick firmly.” So for people with HIV, medication adherence means sticking firmly to an HIV regimen—taking HIV medicines every day and exactly as prescribed.
Adherence to an HIV regimen gives HIV medicines the chance to do their job: to prevent HIV from multiplying and destroying the immune system.
Poor adherence to an HIV regimen allows HIV to destroy the immune system. A damaged immune system makes it hard for the body to fight off infections and certain cancers. Poor adherence also increases the risk of drug resistance.
Drug resistance is when HIV is no longer suppressed by HIV medicines that previously prevented the virus from multiplying.
Drug resistance can develop as HIV multiplies in the body. When HIV multiplies, the virus sometimes mutates (changes form) and makes variations of itself. Variations of HIV that develop while a person is taking HIV medicines can lead to new, drug-resistant strains of HIV. The drug-resistant HIV no longer responds to the HIV medicines that used to suppress the person’s HIV. In other words, the person’s HIV continues to multiply.
Once drug-resistant HIV develops, it remains in the body. Drug resistance limits the number of HIV medicines available to include in a current or future HIV regimen.
Taking HIV medicines every day prevents HIV from multiplying, which reduces the risk that HIV will mutate and produce drug-resistant HIV. Skipping HIV medicines allows HIV to multiply, which increases the risk of drug-resistant HIV developing.
Research shows that a person’s first HIV regimen offers the best chance for long-term treatment success. So adherence is important from the start—when a person first begins taking HIV medicines.
Adherence to an HIV regimen can be difficult for several reasons. For example, side effects from HIV medicines, such as nausea or diarrhea, can make it hard to follow an HIV regimen. A complicated regimen that involves taking several pills at different times every day can also be hard to follow.
The following is a list of other factors that can make medication adherence difficult:
Planning ahead can help. For example, it helps to have a plan in place to manage any issues that can make adherence difficult.
To get tips on adherence, read the AIDSinfo fact sheet: Following an HIV Regimen: Steps to Take Before and After Starting Treatment.