The reason why taking your HIV treatment properly (‘adherence’) is so important is because poor adherence can lead to the development of drug resistance. This can cause your anti-HIV drugs to stop working for you and you may need to change your treatment.
Resistance is a term doctors often use. It means that some HIV cells mutate and carry on reproducing despite treatment. In other words, the drugs don’t work well any more and you become resistant to them.
Every time HIV makes a new copy of itself, it ends up slightly different. Often these differences are not important but sometimes the new copy is different in a way that is ‘resistant’ to the drugs you’ve been taking. This means that it will be able to reproduce again, even when you take the drugs.
Resistance can develop if you don’t take your HIV treatment as prescribed, at the right time every day (often referred to as adherence).
It's possible to have resistance to some drugs even before you start HIV treatment. You may have been infected with a strain of the virus that is already resistant to some anti-HIV drugs. The British HIV Association (BHIVA, the organisation for specialist HIV doctors in the UK) recommends that resistance tests are always carried out when you are diagnosed with HIV, before you start treatment for the first time, and before changing treatment (if your viral load is detectable) to identify whether your strain of HIV is resistant to any anti-HIV drugs.
If you're taking combination therapy, it's important to make sure that enough of the drugs are in your blood all the time so that they can do their job properly. Missed or late doses could mean there are reduced levels of the drugs in your blood. This could allow the virus to make more copies of itself, including drug-resistant copies.
Drug-resistant HIV could lead to the treatment not working, and you not being able to use the same drug (and, sometimes, other drugs in the same class - this is called 'cross-resistance') again in the future. The next combination of drugs you are given might be more complicated to take, or cause more side-effects.
If you're able to take each dose of the combination therapy at the right time each day, then the development of drug-resistant HIV is unlikely. That means the drugs will work for many years.
If you do develop resistance to some drugs, don’t panic – there will still be other treatment options available to you. New drugs have been developed that are effective against drug-resistant strains of HIV.
It's very important that your new combination of drugs is taken properly. If not, you may develop resistance to those too, and this could mean that your HIV becomes very hard to treat.
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This article was last reviewed on
by Anna Peters
Date due for the next review: 6/7/2020
Content Author: S. Corkery (NAM)
Current Owner: Kerri Virani
British HIV Association guidelines for the treatment of HIV-1-positive adults with antiretroviral therapy 2015 (2016 interim update), N Ahmed, B Angus, M Boffito, M Bower, D Churchill, D Dunn, S Edwards, C Emerson, S Fidler, †M Fisher, R Horne, S Khoo, C Leen, N Mackie, N Marshall, F Monteiro, M Nelson, C Orkin, A Palfreeman, S Pett, A Phillips, F Post, A Pozniak, I Reeves, C Sabin, R Trevelion, J Walsh, E Wilkins, I Williams, A Winston
Adherence, by Greta Hughson, NAM Aidsmap, June 2017
HIV drug resistance, World Health Organization, 2017
British HIV Association guidelines for the routine investigation and monitoring of adult HIV-1-positive individuals 2016, Funmi Awosusi, Gary Barker, Marta Boffito, Satyajit Das, Lucy Dorrell, Esther Dixon-Williams, Charlotte Hall, Bridie Howe, Sebastian Kalwij, Nashaba Matin, Eleni Nastouli, Frank Post, Melinda Tenant-Flowers, Erasmus Smit, Dan Wheals
What is drug resistance?, NAM Aidsmap, March 2014
The basics – drug resistance, NAM Aidsmap, January 2017
How does resistance affect treatment, NAM Aidsmap
Transmission of resistant virus, NAM Aidsmap
Taking drugs on time, NAM Aidsmap, January 2017
Reducing the risk of resistance, NAM Aidsmap, March 2014
Transmission of drug resistant HIV, NAM/Aidsmap, March 2014
When to use resistance tests, i-Base, May 2014
Viral load, by Greta Hughson, NAM Aidsmap, May 2017
Williams I et al. BHIVA guidelines for the treatment of HIV-1 positive adults with antiretroviral therapy 2012 (Updated November 2013)
Various people talk about their experiences of living with HIV.
CAB - Citizens Advice Bureau
HIV Drug Interactions
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Equality and Human Rights Commission
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