Body and biology
What Is CYP3A? The Drug-Processing Enzyme Explained
CYP3A · say it: sip-THREE-ayAlso written: CYP3A enzymes, cytochrome P450 3A, CYP3A4, CYP3A5
Short answer
CYP3A is a family of enzymes, mainly in the liver and gut, that break down a large share of commonly used medicines.
What it means
CYP3A stands for cytochrome P450 family 3, subfamily A. It is a small group of enzymes, mainly CYP3A4 and CYP3A5, found mostly in the liver and the lining of the gut. These enzymes chemically change many medicines so the body can remove them. Because so many medicines use this pathway, CYP3A is one of the most important enzyme groups in drug interactions.
Labels mention CYP3A in their 'Drug interactions' or 'Clinical pharmacology' sections. If a medicine is 'metabolized by CYP3A', anything that slows CYP3A (an inhibitor) can raise its level, and anything that speeds it up (an inducer, such as rifampin or St John's wort) can lower it. The label then advises avoiding the combination or adjusting the dose.
CYP3A on a label usually includes CYP3A4, which is the main member. Other enzymes, such as CYP2D6 or CYP2C19, are separate pathways with their own interactions.
Where you may see it
- The 'Drug interactions' and 'Clinical pharmacology' sections of medicine labels
- Pharmacist interaction checks
- Pharmacogenetic (gene test) reports
📄 How it looks on a report
This drug is a substrate of CYP3A. Coadministration with strong CYP3A inducers may decrease its effectiveness.
🙅 What it does not mean
- CYP3A is not a disease or a test result to worry about; it is a normal body enzyme.
- Being 'metabolized by CYP3A' does not mean a medicine is risky; it tells pharmacists what to check.
- Herbal products and foods can affect CYP3A too, not just prescriptions.
🗒️ Questions to ask your doctor
💊 Medicines whose labels mention “CYP3A”
Plain-English explanations of each medicine, from its official FDA label.
- Alprazolam
a benzodiazepine, a type of central nervous system medicine
- Amlodipine
a calcium channel blocker, a type of medicine that relaxes blood vessels
- Apixaban
A factor Xa inhibitor, a blood thinner medicine (anticoagulant)
- Aripiprazole
an atypical antipsychotic medicine
- Artemether and Lumefantrine
an antimalarial medicine, which is a fixed combination of two blood-stage antimalarial ingredients (artemether, an artemisinin derivative, and lumefantrine)
- Colchicine
an alkaloid medicine, a compound obtained from the autumn crocus plant (colchicum autumnale)
- Fluticasone Propionate
A corticosteroid, which is a steroid medicine, given as a nasal spray
- Lamotrigine
An anti-epileptic (seizure) medicine and mood stabilizer. The label describes it as an anti-epileptic drug of the phenyltriazine class that is chemically unrelated to other anti-epileptic drugs.
- Mirtazapine
An antidepressant medicine. The label describes it as having a tetracyclic chemical structure and belonging to the piperazino-azepine group of compounds.
- Nifedipine
a calcium channel blocker of the dihydropyridine type
🔗 Read more from trusted sources
- “CYP3A” on MedlinePlus ↗
US National Library of Medicine
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