The major classes of medications commonly included in cART regimens include nucleotide reverse transcriptase inhibitors (NRTIs), non-nucleotide reverse transcriptase inhibitors (NNRTIs), protease inhibitors (PIs), or integrase inhibitors, all of which interfere with different stages of the HIV infection and replication process.
When I first stumbled across the term cART -- combination antiretroviral therapy -- in the literature, I was confused. Why were certain scientists moving away from the term HAART -- highly active antiretroviral therapy? As it turns out, there is actually a good reason for the change. The term cART is a way for doctors to specify the use of combinations of antiretroviral medication in an age where there is growing interest in monotherapies -- single drug therapies for HIV/AIDS.
Interest in monotherapies springs from a desire to reduce barriers to HIV/AIDS treatment, such as cost and difficulties with adherence, and also to lower the risks of long-term treatment with various HIV drugs, such as premature aging and metabolic dysfunction.
Arguments against the use of monotherapies include concerns that using a single therapy greatly increases the risk of encouraging the formation of drug-resistant strains of the virus and worries that single regimens may simply be not as effective as combination regimens. However, even those who acknowledge that monotherapy may not be useful in all HIV patients are often willing to acknowledge that it might be suitable in certain subpopulations -- such as those individuals who have had good, long-term suppression of their HIV using more traditional combination therapies.
In truth, cART is a more technically accurate term than HAART, because it specifies that a combination of antiretroviral drugs are being used. Although HAART therapy is generally formulated as a combination, the term could theoretically also be used to refer to a highly active monotherapy. Referring specifically to cART allows doctors to clearly distinguish between drug cocktails and single medications, where using the term HAART only addresses theoretical levels of medication activity.
For reasons similar to the ones I used when deciding to call myself the Guide to sexually transmitted diseases instead of the Guide to sexually transmitted infections, I don't foresee switching from writing about HAART to writing about cART any time soon -- at least not on this website. The term STIs was also more medically accurate than STDs, but as with cART, it's less recognized and understood. When writing for the general public, that's a problem. However, being able to debate the terminology problem is great. It's a tool for education.
When someone comes up and asks me why I haven't switched from STDs to STIs, it generates a great discussion about the importance of asymptomatic sexually transmitted infections in sexual health. I suspect that a similar thing will happen if there is a widespread professional shift from HAART to cART. We'll start talking about the various types of drug regimens and have better discussions about when it is appropriate to use them in different situations.