All enzymes · All pairs

CYP1A2 inhibitors, inducers and substrates

CYP1A2 is a liver enzyme that clears caffeine, theophylline, clozapine, olanzapine and tizanidine. Smoking induces it, so levels of these drugs can fall in people who smoke and rise after they quit. The desk files smoking under nicotine, but the induction comes from chemicals in tobacco smoke, not from nicotine itself. Fluvoxamine is a strong inhibitor and ciprofloxacin a moderate one.

This is the desk's mapped set for CYP1A2, taken from the same catalog the desk uses to grade pairs. It is not a complete list. A drug that isn't listed here hasn't been cleared as safe; it just isn't on this list.

Open the desk

What inhibition and induction mean

Inhibition. An inhibitor slows CYP1A2. Drugs that depend on CYP1A2 can build up, so their levels and effects can rise. Reversible inhibition starts as the inhibitor builds up and fades as it clears. Some inhibitors destroy the enzyme, and the effect lasts until the body makes more.

Induction. An inducer makes the body produce more CYP1A2. Levels of drugs that depend on CYP1A2 can fall, and so can their effect. Induction builds over days to weeks and takes about as long to fade after the inducer stops.

Strong, moderate and weak are the desk's grades for how much a perpetrator changes a sensitive substrate's exposure, in FDA's fold-change bins. FDA table of substrates, inhibitors and inducers.

Names with a solid underline open that drug's page of label-sourced pairs. Names with a dotted underline open the desk with that drug.

CYP1A2 inhibitors (19)

Strong inhibitors (2)

≥5-fold ↑ AUC of a sensitive index substrate

Moderate inhibitors (8)

≥2 to <5-fold ↑ AUC

Weak inhibitors (9)

≥1.25 to <2-fold ↑ AUC

CYP1A2 inducers (9)

Moderate inducers (8)

≥50 to <80% ↓ AUC

Weak inducers (1)

≥20 to <50% ↓ AUC

CYP1A2 substrates (35)

Sensitive substrates (8)

Exposure rises the most when CYP1A2 is blocked.

Major-pathway substrates (18)

CYP1A2 is one of the main routes for these.

Minor-pathway substrates (9)

CYP1A2 is a smaller route for these; other routes carry most of the load.

Pair pages that run through CYP1A2 (4)

Label-sourced pair pages where the desk's top finding is a CYP1A2 interaction, grouped by the desk's grade.

Avoid together (4)

Educational reference only. Not FDA-cleared. The Prescribing Information governs.