Old for new

Some symptoms in the first few weeks of treatment may be caused by immune stimulation of your body getting better. So what you think may be side effects may not be related to the drugs at all.

If your initial symptoms are only mild or moderate, seeing whether they settle down before changing treatment, can be good advice. Some side effects become much easier after the first few days and weeks of treatment.

If side effects are more serious or difficult it is important to switch drugs.

Changing to another treatment is usually easy and will not affect your future options.

  • Switching drugs can improve your quality of life and still keep your viral load undetectable.

The decision to change treatment in order to manage side effects will depend on:

  • The other drugs available.
  • Whether the side effects are likely to get worse if don’t change.
  • Whether the side effects are related to drugs. Even though there may not be a known link, this may be a new report, and you may be the first person to experience this.
  • Never just stop or interrupt treatment without contacting your doctor first.
  • If your current combination is not your first treatment, you may have fewer options.

Close monitoring after changing a drug will help you know whether that treatment was causing the symptoms.

Switching nukes

Most combinations involve two nukes. the most commonly used nukes are 3TC, FTC, abacavir and tenofovir.

Guidelines recommend that people using older nukes like AZT, d4T or ddI should switch to tenofovir or abacavir as these drugs have fewer side effects.

So long as you haven’t developed resistance to other nukes, you can switch one for another. The exceptions are:

  • Do not use 3TC and FTC together
  • Do not use AZT and d4T together
  • Do not use d4T and ddI together
  • Do not use ddI and tenofovir together
  • There may be a caution against using abacavir and tenofovir together.

Switching between PIs

Switching from one protease inhibitor (PI) to another is also straight-forward, especially if both PIs are being boosted by 100 mg or 200 mg of ritonavir.

However, some people find ritonavir a difficult drug, even at 100 mg/day.

Although not generally recommended, atazanavir and fosamprenavir can also be used without ritonavir.

If you want to do this, your drug levels need to be checked (see page 19).

Switching NNRTIs

Nevirapine and efavirenz have similar potency but some different side effects.

Nevirapine is more linked with skin rash and liver toxicity – usually in the first 1-2 months of treatment.

Efavirenz is linked to mood disturbance, disturbed sleep patterns and vivid dreams (called CNS side effects) when starting and more rarely in the long term.

You should be able to switch from one to the other without stopping treatment or changing your other drugs.

Two newer NNRTIs may also become more widely used as options for people who have difficulty with efavirenz or nevirapine.

Etravirine (Intelence) is a newer NNRTI that can be used if you have difficulty with nevirapine or efavirenz. Etravirine does not cause CNS side effects.

Rilpivirine (Edurant) is another new NNRTI. It still has CNS side effects, only at half the rate compared to efavirenz.

Switching between different classes

It is also easy to switch between different type of HIV drugs.

For example, people who have difficulty taking efavirenz often switch this drug to atazanavir/ritonavir or to darunavir/ritonavir or to raltegravir.

Similarly, people who have trouble with a protease inhibitor can often switch to an NNRTI or an integrase inhibitor.


Using new drugs and new classes of drugs

One of the advantages of new drugs is that they hopefully have fewer side effects.

There are several new drugs available including some that work in different ways.

These include:

  • Raltegravir (an integrase inhibitor)
  • Maraviroc (a CCR5 inhibitor)
  • Other new drugs in development

Each of these drugs has their own side effects, and advantages as a switch options.

For example, raltegravir does not increase cholesterol or triglycerides.

As each new drug becomes more widely used, they will probably be used as switch options.

Each choice will be based on your individual treatment history.

It may also depend on how the drug is licensed, on drug cost, and on which clinic you attend. If it is important to get access to a new drug, it may be worth changing your clinic.

1 July 2012