When to Change »

… viral replication to below detectable levels as measured on an ultrasensitive viral load assay, and keeping it there.

However, this is not always achievable with a given combination and it sometimes needs to be changed.

There are a number of reasons why a particular combination of anti- HIV drugs fails. These include poor adherence to the drugs and sub-optimal blood levels of anti-HIV drugs.  In the latter case, drug levels may be low in some patients because of an …