An effective regimen should lower the viral load significantly, gradually raise the CD4 count, and not cause important side effects or laboratory abnormalities. If your antiretroviral regimen is successful, it will be continued, with laboratory studies repeated every three to four months thereafter. Your combination of antiretroviral drugs should be changed if you are experiencing serious side effects, if your viral load is rising, if your CD4 count is dropping, or if you develop significant new complications of HIV disease. There are some generally accepted recommendations for modifying antiretroviral regimens that are not working. Cross resistance refers to when a viral strain resistant to one drug is also resistant to another.
Clinical trials evaluate various antiretroviral drug combinations.
Some agents being tested in clinical trials are also available through pharmaceutical company expanded access programs.