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Haloperidol (Haldol)

Antipsychoticprescriptionoral · inferred

High-potency first-generation (typical) antipsychotic and potent D2 receptor antagonist. Available in oral, IM, and long-acting decanoate depot formulations. Strong EPS liability due to high D2 occupancy in the nigrostriatal pathway, with additional risk of QTc prolongation from hERG channel blockade and neuroleptic malignant syndrome. Metabolized primarily by CYP3A4 with contributions from CYP2D6.

Projected serum levels — 5 mg, once daily

Haloperidol (Haldol)
Haloperidol (Haldol) modeled serum levels, 5 mg once daily over 15 days Population-based pharmacokinetic estimate. Steady state reached after approximately 2 days. 0 1.3 2.5 3.8 5 Day 0 Day 4 Day 8 Day 11 Day 15 Time on a regular schedule ≈ steady state · day 2
Haloperidol (Haldol) modeled serum levels with a loading dose of 8.2 mg, then 5 mg once daily The first dose is larger so levels approach steady state faster. 0 1.3 2.5 3.8 5 Day 0 Day 4 Day 8 Day 11 Day 15 Time on a regular schedule

Maintenance schedule: 5 mg once daily (oral).

Loading schedule: 8.2 mg on day 1, then 5 mg once daily — reaching therapeutic levels sooner.

Modeled steady state after ~2 days: peak ≈ 4.4 mg, trough ≈ 2.0 mg body load. Population-based estimate over 15 days for a 5 mg dose at a 70 kg reference body mass — the interactive app scales curves to your doses, timing, and body mass.

Key facts

Category
Antipsychotic
Route modeled
Oral
Model confidence
inferred
Half-life
18 h
Common dose
5 mg
Suggested maximum
20 mg/day
Reference dose range
1–20 mg (single dose)
Suggested cadence
once daily
Validated against
5 mg oral — Cmax 0.004 mg/L at 3 h

Documented interactions

  • contraindicated
    Efavirenz (Sustiva) + Haloperidol (Haldol) CYP induction

    Efavirenz (Sustiva) inducer of CYP3A4 predicted to change Haloperidol (Haldol) AUC by ~0.16x

  • contraindicated
    Rifampin + Haloperidol (Haldol) CYP induction

    Rifampin inducer of CYP3A4 predicted to change Haloperidol (Haldol) AUC by ~0.16x

  • danger
    Amlodipine (Norvasc) + Haloperidol (Haldol) CYP inhibition

    Amlodipine (Norvasc) reversible_inhibitor of CYP3A4 predicted to change Haloperidol (Haldol) AUC by ~2.11x

  • danger
    Ashwagandha (KSM-66) + Haloperidol (Haldol) CYP inhibition

    Ashwagandha (KSM-66) reversible_inhibitor of CYP3A4 predicted to change Haloperidol (Haldol) AUC by ~2.11x

  • danger
    Berberine + Haloperidol (Haldol) CYP inhibition

    Berberine reversible_inhibitor of CYP3A4 predicted to change Haloperidol (Haldol) AUC by ~2.11x

  • danger
    Black Seed Oil (Nigella sativa / Thymoquinone) + Haloperidol (Haldol) CYP inhibition

    Black Seed Oil (Nigella sativa / Thymoquinone) reversible_inhibitor of CYP3A4 predicted to change Haloperidol (Haldol) AUC by ~2.11x

Serum checks 153 modeled interaction pairings for haloperidol (haldol) across your whole stack — absorption conflicts, enzyme inhibition, and nutrient depletion included.

Research behind this entry

  1. Effectiveness of antipsychotic drugs in patients with chronic schizophrenia Lieberman JA et al. · New England Journal of Medicine, 2005 DOI

    Landmark CATIE trial of 1,493 patients comparing haloperidol with olanzapine, quetiapine, risperidone, and ziprasidone. Haloperidol showed comparable overall effectiveness to atypicals but higher rate of extrapyramidal…

  2. Clozapine for the treatment-resistant schizophrenic: a double-blind comparison with chlorpromazine Kane J et al. · Archives of General Psychiatry, 1988 DOI

    Pivotal trial establishing that ~30% of treatment-resistant schizophrenia patients (pre-screened with haloperidol 60 mg/day for 6 weeks) respond to clozapine, defining haloperidol non-response as a therapeutic threshold…

  3. Pharmacokinetics of haloperidol Froemming JS et al. · Clinical Pharmacokinetics, 1989 DOI

    Comprehensive clinical pharmacokinetic review of haloperidol covering bioavailability, protein binding, CYP3A4/2D6 metabolism, reduced-haloperidol interconversion, and the rationale for therapeutic drug monitoring…

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