Antiretroviral drug classes

At present there are six different classes of antiretroviral HIV-drugs available.

Nucleoside Reverse Transcriptase Inhibitors (NRTIs), so called "nukes", interfere with the function of reverse transcriptase, which HIV uses to replicate.

Non-Nucleoside Reverse Transcriptase Inhibitors (NNRTIs) block reverse transcriptase by binding to the reverse transcriptase enzyme. With the enzyme blocked, HIV cannot reproduce.

Protease Inhibitors (PIs) target the HIV protease enzyme called HIV-1 protease, which the virus uses to complete viral replication. By binding to this enzyme, PI's inhibit its activity and therefore prevent viral replication.

Fusion Inhibitors (FIs), also known as entry inhibitors, are a class of antiretroviral drugs that interfere with the binding, fusion and entry of an HIV virion to a human cell.

Integrase Inhibitors (II) are a new drug class that block the action of integrase, an enzyme that integrates genetic material from the virus into its target cell.

CCR5 Antagonists are a new drug class that target the CD4+ co-receptor called CCR5. HIV also binds to this drug class, therefore blocking the HIV from binding to these receptors on the cell. By blocking this receptor, entry of HIV into the cell is inhibited.