Changing treatment due to side-effects
Side-effects are the main reason why people change drugs in their first anti-HIV combination.
Although you may have a good viral-load response after starting antiretroviral therapy, you may find the side effects of some drugs hard to live with. Changing treatment is an option if side-effects cannot be controlled. If your viral load is undetectable, the only drug you will need to change is the one causing the side-effects.
The main problem with changing treatment due to side-effects is that the new combination may not be able to control HIV as well as the old combination. It is also possible that the new drug or drugs you switch to will bring their own unwanted effects.
There is also a bigger risk that the new combination will fail if you have lots of previous experience of treatment.