A class of drugs that inhibit an enzyme used by HIV called "reverse transcriptase". NNRTIs work by a different mechanism than AZT and similar drugs, which also attack reverse transcriptase. NNRTIs are more specifically targeted to HIV than AZT, etc. However, resistance develops more quickly with these drugs; to discourage resistance, NNRTIs are always used in combination with other anti-HIV drugs. Noncompliant: Refers to a patient who is unable to follow a treatment regimen exactly as prescribed. Non-Hodgkin's Lymphoma: A lymphoma made up of B-cells, with nodular or diffuse tumours that may appear in the stomach, liver, brain or bone marrow of people with HIV. Non-Nucleoside Reverse-Transcriptase Inhibitor: see " NNRTI." Norvir®: see " Ritonavir." Nosocomial: Infection or illness acquired in a hospital or other health-care facility. NSAID: Nonsteroidal anti-inflammatory drug. Nucleic Acids: Large, naturally occurring molecules composed of chemical building blocks known as nucleotides or nucleosides. There are two kinds of nucleic acids, DNA and RNA.

Non nucleoside reverse transcriptase inhibitor, the family of antiretrovirals which includes efavirenz, nevirapine and delavirdine.

A group of structurally diverse compounds that bind to the catalytic site of HIV-1's reverse transcriptase . They are quite specific; unlike the nucleoside reverse transcriptase inhibitors, the NNRTIs have no activity against HIV-2 . As noncompetitive inhibitors of reverse transcriptase, their antiviral activity is additive or synergistic with most other antiretroviral agents . However drug-drug interactions may dictate dosage adjustments with protease inhibitors . FDA has approved the NNRTIs nevirapine, delavirdine , and efavirenz for use against HIV.