Is Haldol affected by genetics?

Yes — the active ingredient is metabolized by a gene known to vary between individuals.

Relevant genes: CYP2D6

Haldol is affected by pharmacogenetics through the CYP2D6 gene. Your genotype for this gene can change how your body processes Haldol, which can affect both how well it works and how well you tolerate it. The strongest evidence level on this page is Moderate, based on CPIC or FDA guidelines.

What's in Haldol

haloperidol affected by CYP2D6

Affected by CYP2D6 · DPWG · Moderate evidence

Read the full haloperidol genetics guide →

Haloperidol phenotype recommendations

Published guidance from DPWG on how haloperidol should be dosed or substituted based on your CYP2D6 phenotype.

Phenotype	What it means	Recommendation	Evidence
Ultrarapid Metabolizer CYP2D6	Your body clears haloperidol faster than average, so a standard dose may not be effective. A higher dose or a different antipsychotic is typically recommended.	DPWG Use 1.5 times the normal dose, or choose an alternative. Antipsychotics not metabolised (or metabolised to a much lesser extent) by CYP2D6 include flupentixol, penfluridol, quetiapine, olanzapine, or clozapine.	Moderate
Normal Metabolizer CYP2D6	Your CYP2D6 activity is typical; standard haloperidol dosing applies.	DPWG Use standard haloperidol dosing.	Moderate
Intermediate Metabolizer CYP2D6	Your body clears haloperidol slightly more slowly than average, but the effect is small and no dose change is needed.	DPWG No action is required. Use standard haloperidol dosing.	Moderate
Poor Metabolizer CYP2D6	Your body clears haloperidol slowly, which raises the concentration in your blood and increases side effect risk. A lower dose is typically recommended.	DPWG Use 60% of the normal dose.	Moderate
Indeterminate CYP2D6	We were not able to determine your CYP2D6 metabolism status, so we cannot personalize guidance for haloperidol.	DPWG Use standard haloperidol dosing and monitor response.	—
Not available CYP2D6	We do not have a CYP2D6 result for you, so we cannot personalize guidance for haloperidol.	DPWG Use standard haloperidol dosing and monitor response.	—

Source: DPWG

The gene behind the guidance

CYP2D6 Cytochrome P450 2D6

CYP2D6 is the most clinically important pharmacogene. It metabolizes around a quarter of all prescription drugs, including many antidepressants, opioids, and stimulants. The gene is unusually variable: roughly 7 percent of people are poor metabolizers (they barely activate CYP2D6), and another 1 to 3 percent are ultrarapid metabolizers (their enzyme is overactive).

For most CYP2D6 drugs, poor metabolizers feel stronger effects and more side effects at standard doses, while ultrarapid metabolizers may feel almost nothing. For prodrugs like codeine, the relationship flips: poor metabolizers feel less effect because they can't activate the drug.

See all drugs affected by CYP2D6 →

Browse the full drug-class: Antipsychotics.

Related medications

Find out how your genetics affect Haldol

This page describes the general pharmacogenetics. A Gene2Rx report analyzes your own DNA to tell you which metabolizer group you fall into, across every medication.

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Informational only — not medical advice. Pharmacogenetic guidance describes population-level patterns; your individual response depends on many factors. Never start, stop, or change a medication without talking to your prescribing clinician.