Pharmacology · Integrase strand transfer inhibitors (INSTIs)

Bictegravir !

A second-generation integrase inhibitor sold only in a single tablet with emtricitabine and tenofovir alafenamide.

Updated 2026-11-01

Class: Integrase strand transfer inhibitors (INSTIs)
Enzyme: HIV integrase (intasome)

Also called: BIC

HIV integrase (intasome)Bictegravir

The figure shows bictegravir bound to the two-magnesium active site of the HIV intasome, by cryo-electron microscopy.

Target in 3D: HIV integrase (intasome). PDB structure 6PUW (RCSB PDB, public domain). View the structure at RCSB PDB

Mechanism of action

It binds the two magnesium ions in the active site of integrase bound to viral DNA and blocks strand transfer, like dolutegravir, with a high genetic barrier.

It binds the magnesium ions of the integrase active site
Strand transfer is blocked
Viral DNA is not integrated into the chromosome

Pharmacokinetics

Absorption: Oral, with or without food; polyvalent cations reduce absorption
Metabolism: Liver, by CYP3A4 and UGT1A1

Indications

HIV-1 infection, as a single tablet with emtricitabine and tenofovir alafenamide HIV infection and AIDS →

Adverse effects

Common

Diarrhoea
Nausea
Headache
Mild creatinine rise without kidney damage

Contraindications

Rifamycins, carbamazepine and St John's wort (greatly lower bictegravir)

Key interactions

Rifampicin, carbamazepine, St John's wort: Induce CYP3A4 and UGT1A1 and cause failure: not combined
Metformin: Raises metformin, somewhat less than dolutegravir
Aluminium or magnesium antacids, calcium or iron supplements: They chelate the drug and lower absorption: doses are separated

What is monitored

HIV and hepatitis B tests before starting
Kidney function
Viral load and CD4

Administration and safety

By mouth, one tablet with or without food
Separate antacids, calcium, iron and mineral-containing multivitamins in time, as the label directs
Do not combine with other products containing emtricitabine, lamivudine or tenofovir

Nursing care

Confirm hepatitis B serology
Check TB drugs and anticonvulsants
Teach not to run out of medicine

Pregnancy and breastfeeding

Antiretroviral treatment in pregnancy protects the mother and lowers HIV transmission to the baby; the treating team chooses the regimen.

Test yourself

Think of the answer, then tap the question to see it.

Which drugs is bictegravir co-formulated with?

With emtricitabine and tenofovir alafenamide, in a single tablet.

Why is bictegravir not used with rifampicin?

Rifampicin induces CYP3A4 and UGT1A1, the pathways that clear bictegravir, and its levels fall.

What hepatitis B risk does the bictegravir combination carry?

Its emtricitabine and tenofovir components suppress hepatitis B; stopping it can cause a severe flare.

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HIV infection and AIDS

← Back to the class: Integrase strand transfer inhibitors (INSTIs)

Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.

Sources: Bictegravir, Emtricitabine, and Tenofovir Alafenamide: MedlinePlus Drug Information (MedlinePlus (U.S. National Library of Medicine), 2025); ATCDDD - ATC/DDD Index (WHO Collaborating Centre for Drug Statistics Methodology, 2026); Goodman & Gilman's The Pharmacological Basis of Therapeutics, 14th ed., ch. 64 (McGraw Hill, 2023).

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Representative model, for educational purposes only.