Treatment Adherence & Drug Resistance

Reviewed by: HU Medical Review Board | Last reviewed: September 2019

Adherence and resistance are two common things to consider when thinking about HIV treatment and how successful it might be. Starting and being adherent to a treatment plan reduces the risk of developing medication-resistant HIV, which can become difficult to treat.

The benefits of treatment

As we’ve learned more about HIV and how to treat it, we’ve developed highly effective medications that have changed what it means to live with HIV. HIV is no longer a life-threatening or ending diagnosis for those who are committed to treating the virus. Although HIV is still a chronic or long-term illness, it can be manageable. Without treatment, however, the virus can progress to its most advanced stage, AIDS (acquired immunodeficiency syndrome), in roughly ten years. For some untreated or non-adherent individuals, this progression may vary and can be shorter or longer.1Life expectancy with HIV has increased significantly with the use of ART medicines (antiretroviral therapy). Some recent studies have suggested that for an individual with HIV who takes their ART as directed, life expectancy is approaching or even the same as the general population.2-4

This is especially true for more developed countries. However, anyone who is dedicated to treatment and who maintains regular appointments with their healthcare team, regardless of their background, can increase their life expectancy with HIV.4

Additionally, recent research has suggested that those who achieve and maintain an undetectable viral load have virtually no risk of transmitting the virus to an HIV-negative partner. This idea has been referred to as “undetectable = untransmittable” or “U=U”. Therefore, the risk of HIV transmission to an HIV-negative partner can be reduced when an HIV-positive partner is on ART and taking their medications as prescribed.5-7

What is adherence?

The term adherence, or being described as someone who is adherent to their treatment regimen, refers to someone who is taking their medications exactly as prescribed. Individuals who are adherent to their medication regimen follow their healthcare provider’s instructions, take their medications when they are supposed to, and rarely miss doses of their medicine.

However, we are all human, and missing a dose of medication happens to everyone. Individuals who are adherent to treatment will take their missed dose as soon as they remember, if it’s early enough before their next dose (taking two doses of HIV medications at the same time is not recommended), or will contact their healthcare provider as soon as possible to determine the next best step.

Why is adherence important to HIV treatment?

Regular and consistent treatment is important in controlling HIV for several reasons. Specifically, skipping doses or not taking HIV medications as prescribed can lead to a decreased amount of these medications in the bloodstream, allowing HIV to replicate and become more severe.

When HIV is untreated (or not treated properly) and allowed to multiply in the body, it attacks immune cells called CD4 cells (also called T cells). These cells play an important role in helping us fight off illnesses and foreign invaders. With few to no CD4 cells, the body can be vulnerable to life-threatening conditions, such as cancers, fungal infections, other viral infections, and more. These illnesses can then lead to mortality.8-10

Resistance to HIV treatment options

Another reason consistent treatment is important is to prevent the mutation of HIV as much as possible. When HIV replicates in the body as a result of no treatment or poor adherence to treatment, it has the potential to mutate or change itself.

When HIV mutates, certain medications may not fight the virus as effectively. If HIV continues to mutate, fewer and fewer treatment options may be effective against it, speeding up the progression of HIV. When treatment is taken as directed every day, the virus can be suppressed enough that mutations, and treatment failures, become rare. Treatment for HIV should be started as soon as possible after an HIV diagnosis is made.5,6

An HIV-positive individual may be tested for drug resistance before starting a new HIV treatment regimen or when a current treatment regimen seems to not be controlling the virus as effectively as hoped. Your healthcare provider will let you know if drug resistance testing is required in your situation, and will monitor you for any signs of treatment failure.

Reasons for not adhering to treatment

There are several reasons why an individual may have a hard time taking treatment exactly as directed. Several of these include a lack of consistent medical care or a healthcare provider, a lack of healthcare insurance to cover treatments and appointments, frustration with the pill burden of HIV (some treatment regimens require multiple pills to be taken every day), side effects, and more.

This is why it is incredibly important to find a healthcare provider that you can check-in with regularly throughout treatment about any obstacles you face. There may be resources they have access to that can help, or they may be able to adjust your treatment plan. They may even be able to give you tips on how to combat some common treatment side effects, such as fatigue, nausea, vomiting, diarrhea, headache, insomnia and more. Open communication and regular visits with your healthcare provider may help prevent obstacles before they come up. 11

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