To stop HIV reproducing, it is necessary to take a combination of anti-HIV drugs that each target the virus in a slightly different way. These drugs have a very powerful anti-HIV effect, but they can also have unwanted secondary effects, or side-effects.

It isn’t just anti-HIV drugs that cause side-effects – all medicines (including complementary and alternative medicines, which include so-called ‘natural’ and ‘herbal’ medicines) can have unwanted secondary effects.

Every anti-HIV drug now in use went through years of research. This included clinical trials with hundreds, if not thousands of people with HIV. These trials are to make sure that the drugs work against HIV and are safe to use.  For a drug to be approved for use it has to be shown that the benefits of using it outweigh the side-effects that it causes.

Most of the side-effects that are identified in clinical trials tend to be quite mild – for example diarrhoea, feeling sick, or headache, and they are often temporary. But even mild side-effects can affect your quality of life so it is important to know about the risk of them.

Sometimes more serious side-effects are identified in clinical trials and research – and a particularly serious, even dangerous side-effect, can be an allergic reaction to a drug. However, these are rare.