Drug Resistance and Adherence

Drug resistance  

As HIV multiplies in the body, the virus sometimes mutates (changes form) and produces variations of itself. Variations of HIV that develop while a person is taking HIV medication can lead to drug-resistant strains of HIV, meaning the HIV medications that previously controlled a person's HIV are not effective against the new, drug-resistant strain of HIV. In other words, the HIV medications can't prevent the drug-resistant HIV from multiplying. As a result of drug resistance, one or more HIV medications in a person's HIV regimen may not longer be effective. 

A person can be initially infected with drug-resistant HIV or develop drug-resistant HIV after starting HIV medications. Drug-resistance testing is used to identify which HIV medications (if any) won't be effective against an individual's HIV. Drug-resistance testing results help determine which HIV medicines to include in an HIV treatment regimen.   


Medication adherence means taking HIV medications every day and exactly as prescribed. HIV medications prevent HIV from multiplying. Skipping HIV medicines allows HIV to multiply, which increases the risk that the virus will mutate and produce drug-resistant HIV. Adherence to an effective HIV treatment regimen reduces the risk of drug resistance. 

Here are some tips to help with adherence and reduce the risk of developing drug-resistant forms of HIV:   

  • Once you decide to start treatment, talk with your health care provider to choose an HIV regimen that you can tolerate and that suits your needs. A regimen that meets your needs will make adherence easier. Tell your health care provider about any issues that might make adherence difficult. For example, tell your health care provider if you have a busy schedule that makes it hard to take medicines on time. Your health care provider can recommend resources to help you address any issues before you start taking HIV medicines.
  • When you start treatment, take your HIV medications every day and exactly as prescribed. Use medication aids such as a 7-day pill box or pill diary to stay on track. Try setting a daily alarm on your phone to remind yourself to take your medication, or pick up a portable alarmed pillbox at your local AIDS council or doctor's office. Consider taking your medications with you wherever you go, or keep supplies of your drugs at places you know you'll be (at your partner's house, work, etc.). When travelling, be aware of the different time zones you might be crossing and change the times you take your medication if necessary.   
  • Keep your medical appointments so that your health care provider can monitor your HIV treatment. Having your viral load checked every 3-4 months helps detect resistance and gives you the chance to talk about your treatment plan with your doctor, so that any necessary changes can be made. Appointments are also a good time to ask questions and ask for help to manage problems that make it hard to follow an HIV regimen.
  • Keep a record of which combinations of HIV medications you've taken. 

For more information on adherence and tips on how to manage your HIV medications, refer to this HIV Treatment Adherence fact sheet