Taking your drugs as prescribed is often called ‘adherence’. Adherence to your HIV treatment means:

• Taking all the medicines that make up your HIV treatment combination in the right quantities.
• Taking your medicines at the right time, as close as possible to the same time each day. Usually, this means taking the drug within a two-hour window (up to one hour either side of the set time).
• Following any instructions about food. Some medicines need to be taken with food so they are absorbed properly, but others need to be taken on an empty stomach.
• Checking for interactions with other medicines or drugs. This includes medicines that a doctor prescribes to you, as well as those bought over the counter. It’s also important to know that some herbal and alternative medicines can interact with some anti-HIV drugs, as can some recreational drugs. You may need to avoid some other drugs, or take care with the timing of doses (this is often the case with anti-indigestion drugs).

The best results of HIV treatment are seen in people who take all, or nearly all, of the doses of their drugs in the right way.

HIV treatment has a very powerful anti-HIV effect. Nevertheless, missing doses has been associated with an increase in viral load, a fall in CD4 cell count, and an increased risk of resistance. Near-perfect adherence is also needed to fully suppress HIV replication in cells, even in someone with an undetectable viral load in their blood.

Aim to take all the doses of your medication correctly.

You should try and make an effort to take every dose of your medication at the right time and in the right way. But most people taking HIV treatment occasionally forget to take a dose of their treatment.

What you should do about a missed dose will depend on the circumstances. In most cases, the safest option is to take the missed dose as soon as you realise and then to return to your normal schedule. If you only realise you have missed a dose when you come to the next dose, take the normal dose. Do not take a double dose to compensate for the one you have missed.

If you miss a dose and are not sure what to do, it’s a good idea to ring your clinic for advice.

If you are regularly missing doses of your medication, or taking them late, talk about this with your doctor or other staff at your clinic. Your clinic will be able to offer advice and support. In some cases, it may make sense for you to change your treatment to a drug combination with a lower risk of resistance.

If you vomit (are sick) after taking your HIV treatment, you generally do not need to take another dose, as the drugs will already have been absorbed into your body. Exceptions to this are if it is less than an hour since you took your anti-HIV drugs (or less than four hours if you are taking Eviplera or rilpivirine), or if you see the pills, or remnants of them, in the vomit.

A wide range of factors can have an influence on how well you adhere to your HIV treatment. These differ between people and can change over time. They won’t always be related to your health or medical care. What’s happening in other areas of your life, such as at work, or how you feel about starting treatment, can also affect your ability to take your treatment properly. This means that there’s no single magic solution that can guarantee the best possible adherence for everyone.

Instead, it’s important to think about the factors that are likely to affect you. Doing this can be beneficial if you are about to start or change treatment, or if you are having problems taking your treatment properly.

You may find NAM’s online tool, Get set for HIV treatment helpful when you’re thinking through the issues that might affect your ability to start and stick to treatment.