4. 3 Side effects overview

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

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

Why do side effects occur?

Anything you take into your body has the potential to cause other effects, at least for some people.

The body is very complex. There are also billions of small differences between one person and the next. Sometimes side effects occurs in ways that could never have been predicted from the early studies.

Sometimes rare side effects are only discovered after a drug has been approved.

Are newer drugs likely to be more safe?

It is also very difficult to develop medicines.

Drugs needs to be both effective and safe. New medicines usually need to be better than existing ones. Sometimes they can be more effective at reducing virl load nd sometimes side effects might be easier.

While a medicine is being developed, serious side effects are usually enough to stop further development. Or the company tries to redesign it to be safer.

The aim is always to develop drugs that are safe and tolerable, as well as being better.

This means that the latest HIV drugs are much better than earlier drugs. And future drugs might become even easier.

But technically newer drugs are supported by less evidence. In a similar way, older drugs will be supported by much more evidence over years of uses. It could be argued that side effects of older drugs are therefor better understood.

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 they are only picked up by a special test.
Most only affect some people that use the drug, not everyone.
All drugs have side effects, but not all people taking drugs will experience the same effects and to the same extent.
Rare side effects might only become found after the drugs have been approved and widely used. They might need to be used by many more people over a much longer time than the original studies.

Summary of Product Characteristics (SPC)

Every medicine should have a detailed leaflet about the medicine.

It should include how and when to take the medicine. This leaflet is called the Summary of Product Characteristics or SPC. Sometimes a less technical version is produced for people using the medicine.

These leaflets list all the reported range of possible side effects associated with each drug.

It also includes other useful information, including results from research studies. Also, information about drug interactions with other medicines.

How are side effects reported?

When drugs are first developed, every symptom that occurs is recorded. This is even if it only affects a few people. It also includes things that might not even be caused by the medicine.

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.

The SPC also discusses side effects that are serious or occur most frequently.

If side effects only become known about after the drug has been approved, it might take a while for the SPC to be updated.

Some side effects are only found during monitoring tests, For example, checking your liver and kidneys are working well. Or that your cholesterol levels are okay.

Starting ART for the first time

The risk of side effects can be a big worry if you are about to start ART.

It helps to know what to expect from each drug before choosing your combination.

Ask for information about side effects for the drugs you might take. Ask how likely these are. For example, does this occur in 1 in 10 people (10% chance) or 1 in 100 (1% chance)?

Ask what percentage of people had serious side effects and what percentage were mild?

For modern HIV meds these percentages will all be very low.

Can I change drugs easily?

If side effects are difficult, most people should be able to use a different combination. This will also depend on options in your country,

The US and Europe have approved more than 30 HIV drugs and formulations.

You can’t just mix and match them, but this does mean there are lots of choices. Even countries using WHO guidelines will have choices for first and second combinations.

If one or more of the drugs in your combination are difficult, you can change it for another.

However, the fewer drugs you have used previously, the more choices you have if you need to change.

You can also come back to use the changed drug again in the future, if you need to. Just because you used a drug once, doesn’t mean you have ‘used up your option’ of using it again.

One drug you cannot use again is abacavir. If you have a hypersensitivity reaction to abacavir you must never take it again. Also, if you get a serious skin reaction to an HIV drug, using a similar drug is not recommended.

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 try an alternative. 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?

Most trials still enrol too few women to study sex differences properly.

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

Recent studies reported that the risk of gaining weight with integrase inhibitors, especially dolutegravir, was higher in women than in men.
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?

Getting side effects can make some people less likely to take all their meds. This is why is it so important to talk to your doctor.

ART needs to be taken as prescribed – on time and following any diet advice. Missing doses can lead to drug resistance. It can cause ART to fail.

This is why side effects are an important advocacy issue.

It is also about communication. ART is only effective if it can be taken easily. If this is not the case, the doctor needs to know.

How do I know if a symptom is a side effect?

Sometimes it is difficult to know whether new symptoms are side effects or caused by something else.

Many of the symptoms of side effects are similar to symptoms of illnesses.

This is why it is important to talk to your doctor about anything that worries you. Sometimes you might blame the meds when there might be another cause.

Different treatment is needed when these symptoms relate to a different illness.

Please see the information below and these later sections for practical information about talking to your doctor about side effects.

Getting your doctor to help

Often, for many reasons, communication with your doctor can be difficult.

Sometimes there is limited time. Sometimes things get forgotten. Sometimes there can be a big difference between what is actually going on and what a doctor thinks is going on. This is why side effects are often ignored.

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

So a doctor might think that their patients exaggerate side effects.

But patients generally say that side effects are less difficult than they really are. Or often forget to mention them at all.

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

What happens if side effects continue?

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 2023.