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Abacavir (Ziagen)

Antiretroviralprescriptionoral · inferred

Carbocyclic nucleoside reverse transcriptase inhibitor (NRTI) used as part of combination antiretroviral therapy for HIV-1. Typical dose 600 mg PO once daily or 300 mg twice daily. Plasma half-life is short (~1.5h), but the active intracellular anabolite carbovir-triphosphate has a prolonged intracellular half-life (~21h) permitting once-daily dosing. Oral bioavailability ~83%. Metabolized by alcohol dehydrogenase and glucuronidation (not CYP). CRITICAL: HLA-B*5701 genotyping is mandatory prior to initiation due to a potentially fatal hypersensitivity reaction in carriers.

Projected serum levels — 600 mg, once daily

Abacavir (Ziagen)
Abacavir (Ziagen) modeled serum levels, 600 mg once daily over 15 days Population-based pharmacokinetic estimate. Steady state reached after approximately 1 days. 0 25 50 75 100 Day 0 Day 4 Day 8 Day 11 Day 15 Time on a regular schedule ≈ steady state · day 1

Maintenance schedule: 600 mg once daily (oral).

Modeled steady state after ~1 days: peak ≈ 56.5 mg, trough ≈ 0.001 mg body load. Population-based estimate over 15 days for a 600 mg dose at a 70 kg reference body mass — the interactive app scales curves to your doses, timing, and body mass.

Key facts

Category
Antiretroviral
Route modeled
Oral
Model confidence
inferred
Half-life
1.5 h
Common dose
600 mg
Suggested maximum
600 mg/day
Reference dose range
300–600 mg (single dose)
Suggested cadence
once daily
Validated against
300 mg oral — Cmax 3 mg/L at 0.70 h

Documented interactions

  • moderate
    Carbamazepine (Tegretol) + Abacavir (Ziagen) CYP induction

    Carbamazepine (Tegretol) inducer of UGT predicted to change Abacavir (Ziagen) AUC by ~0.69x

  • moderate
    Phenytoin (Dilantin) + Abacavir (Ziagen) CYP induction

    Phenytoin (Dilantin) inducer of UGT predicted to change Abacavir (Ziagen) AUC by ~0.64x

  • moderate
    Valproic Acid / Divalproex (Depakote) + Abacavir (Ziagen) CYP inhibition

    Valproic Acid / Divalproex (Depakote) reversible_inhibitor of UGT predicted to change Abacavir (Ziagen) AUC by ~1.65x

Serum checks 3 modeled interaction pairings for abacavir (ziagen) across your whole stack — absorption conflicts, enzyme inhibition, and nutrient depletion included.

Research behind this entry

  1. Pharmacokinetics of abacavir and its unique metabolite, carbovir triphosphate, in HIV-infected adults Wang LH et al. · Journal of Acquired Immune Deficiency Syndromes, 2002 DOI

    Clinical PK study defining abacavir plasma half-life (~1.5h) and long intracellular carbovir-TP half-life (~21h) supporting once-daily dosing.

  2. Pharmacokinetics, metabolism, and excretion of the antiretroviral agent abacavir (1592U89) in healthy volunteers McDowell JA et al. · Drug Metabolism and Disposition, 1999 DOI

    Mass-balance and metabolism study characterizing non-CYP metabolism (ADH/UGT), oral bioavailability ~83%, and principal metabolite profile.

2 published studies referenced in the app, each with a plain-language summary.