Treatment training manual

4. 3 Side effects overview

Drugs are generally developed to treat a specific illnesses. When they affect the body in other ways, these effects are called side effects.

Many of the symptoms of side effects are similar to symptoms of illnesses. Different treatment is needed when these symptoms relate to illnesses.

Side effects are also called adverse events (AEs) or drug toxicity.

Why do side effects occur?

Although drugs are designed to work against specific illnesses, they sometimes interfere with other ways that your body works.

It is difficult to develop effective drugs. Before being approved drugs have been studied to minimise toxicity. Often, the development of very promising drug is stopped because of side effects. The aim is always to develop safer and more tolerable, as well as better drugs.

Most people – people living with HIV, doctors and researchers – recognise that the current drugs are significantly better and esier to take than earlier drugs. Although current drugs are not perfect, newer drugs in the future might be even easier to take.

Do all drugs have side effects?

Most drugs have some side effects for some people. In the majority of cases these side effects are mild and easy to manage.

  • Some side effects are so mild that they are unnoticed or only picked up by a special test.
  • Some only affect a small proportion of people that use the drug.
  • Some rare side effects only become apparent after the drugs have been licensed and approved. This is after many more people use them over a much longer period than the original studies.
  • All drugs have side effects, but not all people taking drugs will experience the same effects and to the same extent.

Summary of Product Characteristics

The leaflet included in the packaging with a drug is called the Summary of Product Characteristics or SPC.

This leaflet lists all the reported range of possible side effects associated with each drug.

It also includes other useful information, including how the drug needs to be taken and interactions with other medicines.

How are side effects reported?

When drugs are first studied, every symptom that occurs in the study is recorded. This is even if it only affects a few people, and even if it cannot be directly linked to the drug being studied.

This means that if you look at the SPC leaflet you usually find a long and daunting list of potential side effects. It does not mean you are going to get all these side effects.

Side effects that are serious or occur most frequently are also usually discussed in more detail.

If side effects only become apparent after the drug has been approved, the SPC may not list it. It usually takes time for this to be updated in a new version of the SPC.

Starting ART for the first time

The risk of side effects can be a big worry if you are about to start ART for the first time. It helps to know what to expect from each drug before choosing your combination.

Ask for information about each of the drugs you might take, including the likelihood of side effects occurring. For example, what percentage of people had side effects related to each drug and how serious they were?

You may be asked to consider entering a study looking at side effects in different combinations and these studies are important to define the extent of side effects in different combinations.

Can I change drugs easily?

If starting ART for the first time, you will have more options to choose from. You will have more options to change drugs until you find a combination that works and is easy to take.

There are already over 30 approved ARV drugs and formulations. While you can’t quite mix and match them all, you have a lot of choice. If one or more of the drugs in your combination are difficult to tolerate, you can change it for another.

Often people are not given a choice when starting treatment. However, the fewer drugs you have used previously, the more choices you have if you need to change.

If you change a drug because of side effects, you can usually use it again later if you need to. Just because you used a drug once, doesn’t mean you have ‘used up your option’ of using it again in the future.

The only drug you cannot use again is abacavir. If you have a hypersensitivity reaction to abacavir you must never take it again.

Some side effects improve after the first few weeks or months, but some don’t.

You do not have to continue with a drug to prove anything to yourself or to please your doctor. If something is wrong, ask your doctor to change it to something else. Some drugs are just not for everyone.

Can I predict the side effects I may get?

Generally you cannot predict how difficult or easy you will find it to take any particular drug.

Sometimes, if you already have similar symptoms related to the side effects, these may make the risk of side effects greater.

For example:

  • If you have raised liver enzymes, these may increase higher still if you use nevirapine.
  • If you have high cholesterol or triglycerides before treatment, these are more likely to increase if you use some protease inhibitors.

Are side effects different in men and women?

Many trials in the past enrolled far too few women to study gender differences properly.

Sometimes differences in side effects between men and women are reported later.

  • Women have shown higher rates of side effects in some nevirapine studies (both liver toxicity and rash), which highlights the importance of careful monitoring.
  • With lipodystrophy (fat loss in your arms, legs or face, or fat gain in abdomen, breasts, and shoulders), women are more likely to report symptoms of fat accumulation rather than fat loss.

What about side effects and adherence?

Whether you are starting your first treatment or have been using HIV drugs for a long time, your doctor should have talked to you about the importance of adherence.

Adherence means taking the meds in your combination exactly as they are prescribed – on time and following any diet advice.

Getting your doctor to do something

There can be a big difference between what is actually going on and what a doctor thinks is going on – and this is why side effects are often ignored.


  • Some doctors think that their patients overestimate side effects.
  • Most patients underestimate side effects.

Doctors generally think that their patients exaggerate side effects, and that they are not really as bad as their patients say.

Patients generally say that side effects are less difficult than they really are, or often forget to mention them at all.

Regular blood tests will check for some side effects.

If you have any side effects make sure your doctor takes these seriously…

What happens if side effects persist?

If the first treatment you are given to help with a side effect does not work, there are usually others that you can use.

In this manual we have listed a range of options, including alternative treatments, for each of the main side effects. If one doesn’t work – try the other options.

Changing or stopping treatment are important options that you can discuss with your doctor.

Last updated: 1 January 2016.