Is Starlix affected by genetics?

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

Relevant genes: CYP2C9

Starlix is affected by pharmacogenetics through the CYP2C9 gene. Your genotype for this gene can change how your body processes Starlix, 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 Starlix

nateglinide affected by CYP2C9

Affected by CYP2C9 · FDA · Moderate evidence

Read the full nateglinide genetics guide →

Nateglinide phenotype recommendations

Published guidance from FDA on how nateglinide should be dosed or substituted based on your CYP2C9 phenotype.

Phenotype	What it means	Recommendation	Evidence
Normal Metabolizer CYP2C9	Your body processes nateglinide at a normal rate. The standard dose should work as expected.	FDA Initiate therapy with recommended starting dose.	—
Intermediate Metabolizer CYP2C9	Your body breaks down nateglinide slightly slower than normal. The standard dose should work as expected.	FDA Initiate therapy with recommended starting dose.	—
Poor Metabolizer CYP2C9	Your body breaks down nateglinide much more slowly than normal, causing the drug to build up and raising the risk of dangerously low blood sugar. A lower dose and closer monitoring are recommended.	FDA Reduce nateglinide dose and increase monitoring for hypoglycemia. Refer to FDA labeling for specific dosing recommendations.	Moderate
Indeterminate CYP2C9	The impact of your genotype on response to this drug is unknown	FDA Initiate therapy with recommended starting dose.	—
Not available CYP2C9	The impact of your genotype on response to this drug is unknown	FDA Initiate therapy with recommended starting dose.	—

Source: FDA

The gene behind the guidance

CYP2C9 Cytochrome P450 2C9

CYP2C9 metabolizes warfarin, phenytoin, celecoxib, and some NSAIDs. Variants that reduce its activity are most consequential for warfarin, where even small changes in drug clearance translate into very different doses (and a real bleeding risk if missed).

Poor metabolizers need substantially lower warfarin doses to hit the same INR target.

See all drugs affected by CYP2C9 →

Related medications

Find out how your genetics affect Starlix

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.