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Raltegravir (Isentress)

Antiretroviralprescriptionoral · inferred

First-in-class HIV integrase strand transfer inhibitor (INSTI). Original formulation 400 mg PO BID; HD formulation 1200 mg (two 600 mg tabs) QD. Plasma half-life ~9h. Oral bioavailability variable and influenced by food (~moderate). Metabolized primarily by UGT1A1 glucuronidation (non-CYP), fewer drug interactions than boosted PIs. Well tolerated; rare myopathy/CPK elevation and rhabdomyolysis reported.

Projected serum levels — 400 mg, twice daily

Raltegravir (Isentress)
Raltegravir (Isentress) modeled serum levels, 400 mg twice daily over 15 days Population-based pharmacokinetic estimate. Steady state reached after approximately 2 days. 0 125 250 375 500 Day 0 Day 4 Day 7 Day 11 Day 15 Time on a regular schedule ≈ steady state · day 2
Raltegravir (Isentress) modeled serum levels with a loading dose of 696 mg, then 400 mg twice daily The first dose is larger so levels approach steady state faster. 0 125 250 375 500 Day 0 Day 4 Day 7 Day 11 Day 15 Time on a regular schedule

Maintenance schedule: 400 mg twice daily (oral).

Loading schedule: 696 mg on day 1, then 400 mg twice daily — reaching therapeutic levels sooner.

Modeled steady state after ~2 days: peak ≈ 276 mg, trough ≈ 144 mg body load. Population-based estimate over 15 days for a 400 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
9 h
Common dose
400 mg
Suggested maximum
1.2k mg/day
Reference dose range
200–1.2k mg (single dose)
Suggested cadence
twice daily
Validated against
400 mg oral — Cmax 2 mg/L at 3 h

Documented interactions

  • danger
    Efavirenz (Sustiva) + Raltegravir (Isentress) CYP induction

    Efavirenz (Sustiva) inducer of UGT1A1 predicted to change Raltegravir (Isentress) AUC by ~0.50x

  • danger
    Glecaprevir + Raltegravir (Isentress) CYP inhibition

    Glecaprevir reversible_inhibitor of UGT1A1 predicted to change Raltegravir (Isentress) AUC by ~3.33x

  • danger
    Phenobarbital + Raltegravir (Isentress) CYP induction

    Phenobarbital inducer of UGT1A1 predicted to change Raltegravir (Isentress) AUC by ~0.40x

  • danger
    Rifampin + Raltegravir (Isentress) CYP induction

    Rifampin inducer of UGT1A1 predicted to change Raltegravir (Isentress) AUC by ~0.33x

  • danger
    St. John's Wort (Hypericum perforatum) + Raltegravir (Isentress) CYP induction

    St. John's Wort (Hypericum perforatum) inducer of UGT1A1 predicted to change Raltegravir (Isentress) AUC by ~0.50x

  • moderate
    Carvedilol (Coreg) + Raltegravir (Isentress) Transporter inhibition

    Carvedilol (Coreg) inhibitor of P-gp may alter Raltegravir (Isentress) absorption / distribution

Serum checks 26 modeled interaction pairings for raltegravir (isentress) across your whole stack — absorption conflicts, enzyme inhibition, and nutrient depletion included.

Research behind this entry

  1. Safety, tolerability, and pharmacokinetics of raltegravir after single and multiple doses in healthy subjects Iwamoto M et al. · Clinical Pharmacology & Therapeutics, 2008 DOI

    First-in-human PK study establishing raltegravir's ~9h terminal half-life, UGT1A1-mediated glucuronidation, and dose-proportional exposure.

  2. Raltegravir once daily or twice daily in previously untreated patients with HIV-1 (ONCEMRK) Eron JJ et al. · Lancet Infectious Diseases, 2013 DOI

    Phase 3 non-inferiority trial supporting once-daily 1200 mg HD formulation versus 400 mg BID.

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