Here are all the antiretroviral drugs approved in the U.S. at the end of July 2003. We list them by drug class:

• NRTIs (nucleoside reverse transcriptase inhibitors) target reverse transcriptase (an enzyme of HIV), by providing false building blocks that the enzyme puts into new copies of the virus it is building. Occasionally the false building blocks can be incorporated into human DNA, causing toxicity.

• NNRTIs (non-nucleoside reverse transcriptase inhibitors) target the same reverse transcriptase enzyme, but do not provide false building blocks.

• Protease inhibitors target HIV protease, an enzyme necessary for late steps in the formation of new copies of HIV. Some protease inhibitors may inhibit certain human proteases as well, causing toxicity.

• Fusion inhibitors block infection early by preventing HIV from fusing with and entering a human cell. Only one fusion inhibitor has been approved so far, and this particular drug is expensive to manufacture and difficult to use.

None of these drugs can be taken alone to treat an established HIV infection. They must be used in well-designed combination regimens.

NRTIs

Abacavir (Ziagen)
Didanosine -- ddI (Videx)
Emtricitabine -- FTC (Emtriva -- previous brand name Coviracil)
Lamivudine -- 3TC (Epivir)
Stavudine -- d4T (Zerit)
Tenofovir DF (Viread)
Zalcitabine -- ddC (Hivid)
Zidovudine -- AZT (Retrovir)

NNRTIs

Delavirdine (Rescriptor)
Efavirenz (Sustiva, brand name Stocrin in many countries)
Nevirapine (Viramune)

Protease Inhibitors

Amprenavir (Agenerase)
Atazanavir (Reyataz, formerly named Zrivada)
Indinavir (Crixivan)
Lopinavir + ritonavir (Kaletra)
Nelfinavir (Viracept)
Ritonavir (Norvir)
Saquinavir (Fortovase, earlier formulation Invirase)

Fusion Inhibitors

Enfuvirtide (Fuzeon)

Combination Medications

These brand names are combinations of two or three of the medicines above in one pill. Combinations reduce the number of pills patients must take each day. They can also help meet requirements of health plans that limit the number of "prescriptions" per month regardless of medical need.

Combivir (AZT + 3TC)
Trizivir (abacavir + AZT + 3TC)

ISSN # 1052-4207

Copyright 2003 by John S. James. Permission granted for noncommercial reproduction, provided that our address and phone number are included if more than short quotations are used.