More about Pharmacogenetics Testing
What should I do about the results of my pharmacogenetic testing?
Do not change or stop taking any medicine based on a report from a genetic test you took on your own. Discuss the results of the genetic test with your health care provider, including whether the medication label includes information on how to use genetic information to determine dosage, and whether your health care provider recommends changes to your treatment. Medicine should always be taken as prescribed by your health care provider.
Is pharmacogenetic testing the same for everyone?
Each patient’s genetic makeup is only one of many factors that may impact drug concentrations and response, highlighting the fact that information provided in this table is limited to certain pharmacogenetic associations only and does not provide comprehensive information needed for safe and effective use of a drug.
The FDA recognizes that various other pharmacogenetic associations exist that are not listed and will be updated periodically with additional pharmacogenetic associations supported by sufficient scientific evidence.
Pharmacogenetic Associations for which the Data Support Therapeutic Management Recommendations (continuation)
| Aripiprazole Lauroxil | CYP2D6 | poor metabolizers | Results in higher systemic concentrations. Dosage adjustment is recommended. Refer to FDA labeling for specific dosing recommendations. |
| Atomoxetine | CYP2D6 | poor metabolizers | Results in higher systemic concentrations and higher adverse reaction risk. Adjust titration interval and increase dosage if tolerated. Refer to FDA labeling for specific dosing recommendations. |
| Azathioprine | TPMT and/or NUDT15 | intermediate or poor metabolizers | Alters systemic active metabolite concentration and dosage requirements. Results in higher adverse reaction risk (myelosuppression). Consider alternative therapy in poor metabolizers. Dosage reduction is recommended in intermediate metabolizers for NUDT15 or TPMT. Intermediate metabolizers for both genes may require more substantial dosage reductions. Refer to FDA labeling for specific dosing recommendations. |
| Belinostat | UGT1A1 | *28/*28 (poor metabolizers) | May result in higher systemic concentrations and higher adverse reaction risk. Reduce starting dose to 750 mg/m2 in poor metabolizers. |
| Brexpiprazole | CYP2D6 | poor metabolizers | Results in higher systemic concentrations. Dosage adjustment is recommended. Refer to FDA labeling for specific dosing recommendations. |
| Brivaracetam | CYP2C19 | intermediate or poor metabolizers | Results in higher systemic concentrations and higher adverse reaction risk. Consider dosage reductions in poor metabolizers. |
| Capecitabine | DPYD | intermediate or poor metabolizers | Results in higher adverse reaction risk (severe, life-threatening, or fatal toxicities). No dosage has proven safe in poor metabolizers, and insufficient data are available to recommend a dosage in intermediate metabolizers. Withhold or discontinue in the presence of early-onset or unusually severe toxicity. |
| Carbamazepine | HLA-B | *15:02 allele positive | Results in higher adverse reaction risk (severe skin reactions). Avoid use unless potential benefits outweigh risks and consider risks of alternative therapies. Patients positive for HLA-B*15:02 may be at increased risk of severe skin reactions with other drugs that are associated with a risk of Stevens Johnson Syndrome/Toxic Epidermal necrolysis (SJS/TEN). Genotyping is not a substitute for clinical vigilance. |
| Celecoxib | CYP2C9 | poor metabolizers or *3 carriers | Results in higher systemic concentrations. Reduce starting dose to half of the lowest recommended dose in poor metabolizers. Consider alternative therapy in poor metabolizers with juvenile rheumatoid arthritis. |
| Citalopram | CYP2C19 | poor metabolizers | Results in higher systemic concentrations and adverse reaction risk (QT prolongation). The maximum recommended dose is 20 mg. |
| Clobazam | CYP2C19 | intermediate or poor metabolizers | Results in higher systemic active metabolite concentrations. Poor metabolism results in higher adverse reaction risk. Dosage adjustment is recommended. Refer to FDA labeling for specific dosing recommendations. |
| Clopidogrel | CYP2C19 | intermediate or poor metabolizers | Results in lower systemic active metabolite concentrations, lower antiplatelet response, and may result in higher cardiovascular risk. Consider use of another platelet P2Y12 inhibitor. |
| Clozapine | CYP2D6 | poor metabolizers | Results in higher systemic concentrations. Dosage reductions may be necessary. |
| Codeine | CYP2D6 | ultrarapid metabolizers | Results in higher systemic active metabolite concentrations and higher adverse reaction risk (life-threatening respiratory depression and death). Codeine is contraindicated in children under 12 years of age. |
| Deutetrabenazine | CYP2D6 | poor metabolizers | Results in higher systemic concentrations and adverse reaction risk (QT prolongation). The maximum recommended dosage should not exceed 36 mg (maximum single dose of 18 mg). |
| Dronabinol | CYP2C9 | intermediate or poor metabolizers | May result in higher systemic concentrations and higher adverse reaction risk. Monitor for adverse reactions. |
| Eliglustat | CYP2D6 | ultrarapid, normal, intermediate, or poor metabolizers | Alters systemic concentrations, effectiveness, and adverse reaction risk (QT prolongation). Indicated for normal, intermediate, and poor metabolizer patients. Ultrarapid metabolizers may not achieve adequate concentrations to achieve a therapeutic effect. The recommended dosages are based on CYP2D6 metabolizer status. Coadministration with strong CYP3A inhibitors is contraindicated in intermediate and poor CYP2D6 metabolizers. Refer to FDA labeling for specific dosing recommendations. |
| Erdafitinib | CYP2C9 | *3/*3 (poor metabolizers) | May result in higher systemic concentrations and higher adverse reaction risk. Monitor for adverse reactions. |
| Flibanserin | CYP2C19 | poor metabolizers | May result in higher systemic concentrations and higher adverse reaction risk. Monitor patients for adverse reactions. |
| Flurbiprofen | CYP2C9 | poor metabolizers or *3 carriers | Results in higher systemic concentrations. Use a reduced dosage in poor metabolizers. |
| Fluorouracil | DPYD | intermediate or poor metabolizer | Results in higher adverse reaction risk (severe, life-threatening, or fatal toxicities). No dosage has proven safe in poor metabolizers and insufficient data are available to recommend a dosage in intermediate metabolizers. Withhold or discontinue in the presence of early-onset or unusually severe toxicity. |
| Gefitinib | CYP2D6 | poor metabolizers | Results in higher systemic concentrations and higher adverse reaction risk. Monitor for adverse reactions. |
| Iloperidone | CYP2D6 | poor metabolizers | Results in higher systemic concentrations and higher adverse reaction risk (QT prolongation). Reduce dosage by 50%. |
| Irinotecan | UGT1A1 | *28/*28 (poor metabolizers) | Results in higher systemic active metabolite concentrations and higher adverse reaction risk (severe neutropenia). Consider reducing the starting dosage by one level and modify the dosage based on individual patient tolerance. |
| Lofexidine | CYP2D6 | poor metabolizers | Results in higher systemic concentrations and higher adverse reaction risk. Monitor for orthostatic hypotension and bradycardia. |
| Meclizine | CYP2D6 | ultrarapid, intermediate, or poor metabolizers | May affect systemic concentrations. Monitor for adverse reactions and clinical effect. |
| Meloxicam | CYP2C9 | poor metabolizers or *3 carriers | Results in higher systemic concentrations. Consider dose reductions in poor metabolizers. Monitor patients for adverse reactions. |
| Metoclopramide | CYP2D6 | poor metabolizers | Results in higher systemic concentrations and higher adverse reaction risk. The recommended dosage is lower. Refer to FDA labeling for specific dosing recommendations. |
| Mercaptopurine | TPMT and/or NUDT15 | intermediate or poor metabolizers | Alters systemic active metabolite concentration and dosage requirements. Results in higher adverse reaction risk (myelosuppression). Initial dosages should be reduced in poor metabolizers; poor metabolizers generally tolerate 10% or less of the recommended dosage. Intermediate metabolizers may require dosage reductions based on tolerability. Intermediate metabolizers for both genes may require more substantial dosage reductions. Refer to FDA labeling for specific dosing recommendations. |
| Mivacurium | BCHE | intermediate or poor metabolizers | Results in higher systemic concentrations and higher adverse reaction risk (prolonged neuromuscular blockade). Avoid use in poor metabolizers. |
| Oliceridine | CYP2D6 | poor metabolizers | Results in higher systemic concentrations and higher adverse reaction risk (respiratory depression and sedation). May require less frequent dosing. |
| Pantoprazole | CYP2C19 | poor metabolizers | Results in higher systemic concentrations. Consider dosage reduction in children who are poor metabolizers. No dosage adjustment is needed for adult patients who are poor metabolizers. |
| Pimozide | CYP2D6 | poor metabolizers | Results in higher systemic concentrations. Dosages should not exceed 0.05 mg/kg in children or 4 mg/day in adults who are poor metabolizers and dosages should not be increased earlier than 14 days. |
| Piroxicam | CYP2C9 | intermediate or poor metabolizers | Results in higher systemic concentrations. Consider reducing dosage in poor metabolizers. |
| Pitolisant | CYP2D6 | poor metabolizers | Results in higher systemic concentrations. Use lowest recommended starting dosage. Refer to FDA labeling for specific dosing recommendations. |
| Propafenone | CYP2D6 | poor metabolizers | Results in higher systemic concentrations and higher adverse reaction risk (arrhythmia). Avoid use in poor metabolizers taking a CYP3A4 inhibitor. |
| Sacituzumab Govitecan-hziy | UGT1A1 | *28/*28 (poor metabolizers) | May result in higher systemic concentrations and adverse reaction risk (neutropenia). Monitor for adverse reactions and tolerance to treatment. |
| Siponimod | CYP2C9 | intermediate or poor metabolizers | Results in higher systemic concentrations. Adjust dosage based on genotype. Do not use in patients with CYP2C9 *3/*3 genotype. Refer to FDA labeling for specific dosing recommendations. |
| Succinylcholine | BCHE | intermediate or poor metabolizers | Results in higher systemic concentrations and higher adverse reaction risk (prolonged neuromuscular blockade). Avoid use in poor metabolizers. May administer test dose to assess sensitivity and administer cautiously via slow infusion. |
| Tacrolimus | CYP3A5 | intermediate or normal metabolizers | Results in lower systemic concentrations, lower probability of achieving target concentrations and may result in higher rejection risk. Measure drug concentrations and adjust dosage based on trough whole blood tacrolimus concentrations. |
| Tetrabenazine | CYP2D6 | poor metabolizers | Results in higher systemic concentrations. The maximum recommended single dose is 25 mg and should not exceed 50 mg/day. |
| Thioguanine | TPMT and/or NUDT15 | intermediate or poor metabolizers | Alters systemic active metabolite concentration and dosage requirements. Results in higher adverse reaction risk (myelosuppression). Initial dosages should be reduced in poor metabolizers; poor metabolizers generally tolerate 10% or less of the recommended dosage. Intermediate metabolizers may require dosage reductions based on tolerability. Intermediate metabolizers for both genes may require more substantial dosage reductions. Refer to FDA labeling for specific dosing recommendations. |
| Thioridazine | CYP2D6 | poor metabolizers | Results in higher systemic concentrations and higher adverse reaction risk (QT prolongation). Predicted effect based on experience with CYP2D6 inhibitors. Contraindicated in poor metabolizers. |
| Tramadol | CYP2D6 | Ultrarapid metabolizers3 | Results in higher systemic and breast milk active metabolite concentrations, which may result in respiratory depression and death. Contraindicated in children under 12 and in adolescents following tonsillectomy/adenoidectomy. Breastfeeding is not recommended during treatment. |
| Valbenazine | CYP2D6 | poor metabolizers | Results in higher systemic active metabolite concentrations and higher adverse reaction risk (QT prolongation). Dosage reductions may be necessary. |
| Venlafaxine | CYP2D6 | poor metabolizers | Alters systemic parent drug and metabolite concentrations. Consider dosage reductions. |
| Vortioxetine | CYP2D6 | poor metabolizers | Results in higher systemic concentrations. The maximum recommended dose is 10 mg. |
| Warfarin | CYP2C9 | intermediate or poor metabolizers | Alters systemic concentrations and dosage requirements. Select initial dosage, taking into account clinical and genetic factors. Monitor and adjust dosages based on INR. |
| Warfarin | CYP4F2 | V433M variant carriers | May affect dosage requirements. Monitor and adjust doses based on INR. |
| Warfarin | VKORC1 | -1639G>A variant carriers | Alters dosage requirements. Select initial dosage, taking into account clinical and genetic factors. Monitor and adjust dosages based on INR. |
