What is medication adherence?

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.

Why is adherence to an HIV regimen important?

Adherence to an HIV regimen gives HIV medicines the chance to do their job: to prevent HIV from multiplying and destroying the immune system. HIV medicines help people with HIV live longer, healthier lives. HIV medicines also reduce the risk of HIV transmission.

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 and HIV treatment failure.

What is drug resistance?

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. HIV medicines that used to suppress the person’s HIV are not effective against the new drug-resistant 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.

What is the connection between medication adherence and drug resistance?

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.

Why is medication adherence sometimes difficult?

Adherence to an HIV regimen can be difficult for several reasons. For example, side effects from some HIV medicines, such as nausea or diarrhea, can make it hard to follow an HIV regimen. When an HIV regimen includes several HIV medicines, it’s easy to forget how many pills to take and when to take them.

The following factors can also make medication adherence difficult:

• Side effects from interactions between HIV medicines and other medicines a person may take
• Trouble swallowing pills or other difficulty taking medicines
• A busy schedule, shift work, or travel away from home that makes it hard to take medicines on time
• Illness or depression
• Alcohol or drug use that interferes with the activities of daily life
• Fear of disclosing one’s HIV-positive status to others  
• Lack of health insurance to cover the cost of HIV medicines

Before starting HIV medicines, it helps to have strategies in place to maintain adherence. Strategies may include using a 7-day pill box or using an app (for example, the AIDSinfo Drug Database app) to set daily pill reminders. Also, health care providers can provide helpful referrals and resources for anticipated adherence challenges. People can work with their health care providers to select an HIV regimen that works best for their needs and lifestyle.  

To get more tips on adherence, read the AIDSinfo fact sheet: Following an HIV Regimen: Steps to Take Before and After Starting HIV Medicines.

This fact sheet is based on information from the following sources.

• From the Department of Health and Human Services: Guidelines for the Use of Antiretroviral Agents in HIV-1-Infected Adults and Adolescents/Adherence to Antiretroviral Therapy 
• From the Health Resources and Services Administration: Guide for HIV/AIDS Clinical Care/HIV Treatment/Adherence