Antiretroviral therapy (ART)
also: HAART · HIV treatment · INSTI · NRTI · NNRTI · PI
Overview
Combination therapy for HIV — typically two NRTIs plus a third agent (now usually an integrase inhibitor). Goal: undetectable viral load (U=U: untransmittable). Lifelong.
Mechanism
Each class blocks a different step of the HIV life cycle. NRTIs (e.g. tenofovir, emtricitabine, abacavir) are nucleoside analogues that terminate reverse-transcription. NNRTIs bind/inhibit reverse transcriptase allosterically. Integrase strand-transfer inhibitors (INSTIs, "-tegravir") block proviral DNA integration. Protease inhibitors ("-navir") block viral maturation. Combining classes prevents resistance.
Indications
- HIV-1 infection (start ART in everyone, regardless of CD4)
The agents
OD
Tenofovir: renal + bone toxicity (TDF) — TAF gentler.
OD
First-line third agent; weight gain; few interactions.
OD nocte
CNS/vivid dreams; CYP inducer.
HLA-B*57:01 test before use — hypersensitivity.
GI upset, lipid effects, many interactions.
Adverse effects
Screen HLA-B*57:01 first — fever, rash, GI, do not rechallenge.
On starting ART with low CD4.
Cautions & contraindications
CYP3A4 — check statins, rifampicin, contraception, PPIs.
Interactions
- PIs/cobicistat inhibit CYP3A4 (↑statins, sedatives)
- Efavirenz/rifampicin induce CYP
- INSTIs chelated by antacids/divalent cations — separate dosing
Monitoring & kinetics
CD4 count + HIV viral load,U&E (tenofovir), bone health, lipids,HLA-B*57:01 before abacavir
Oral combinations, usually once daily (single-tablet regimens). Adherence is critical to prevent resistance.
Source: BHIVA — HIV treatment guidelines · BNF — Antiretrovirals