Yes — the active ingredient is metabolized by a gene known to vary between individuals.
Relevant genes: CYP2C9
Syndros is affected by pharmacogenetics through the CYP2C9 gene. Your genotype for this gene can change how your body processes Syndros, which can affect both how well it works and how well you tolerate it. The strongest evidence level on this page is Strong, based on CPIC or FDA guidelines.
Published guidance from FDA on how dronabinol should be dosed or substituted based on your CYP2C9 phenotype.
| Phenotype | What it means | Recommendation | Evidence |
|---|---|---|---|
|
Normal Metabolizer
CYP2C9
|
Your body processes dronabinol 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 dronabinol more slowly than normal, which may cause the drug to build up and increase the risk of side effects. Extra monitoring is recommended. |
FDA
Initiate therapy with standard dose and monitor closely for adverse reactions due to potential for higher systemic concentrations.
|
Moderate |
|
Poor Metabolizer
CYP2C9
|
Your body breaks down dronabinol much more slowly than normal, causing the drug to build up and raising the risk of heart rhythm problems. A lower maximum dose is recommended. |
FDA
Reduce maximum dosage to no more than 36 mg daily (maximum single dose of 18 mg) and monitor for QT prolongation and other adverse reactions.
|
Strong |
|
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
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.
Browse the full drug-class: Antiemetics.
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.
Get your report Look up another medicationInformational 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.