How do you memorize CYP inducers and inhibitors?

Ok. So let’s do the inducers. Now these increase the activity of the cytochrome p450 enzymes and so the drugs that the patient is taking that are metabolized by cytochrome p450 enzymes will now get

What are inhibitors of CYP450?

Examples of cytochrome P450 inhibitors are erythromycin, ketoconazole, diltiazem, colchicine, and the fluoroquinolones [61].

What drugs are metabolized by CYP?

Drugs which are known to be metabolized by CYP1A2 include theophylline, caffeine, imipramine, paracetamol and phenacitin [12]. Alteration in CYP1A2 activity, for example by smoking, may alter the requirements for theophylline among asthmatics [13] and haloperidol among psychiatric patients [14].

What does 450 mean in CYP450?

The term “P450” is derived from the spectrophotometric peak at the wavelength of the absorption maximum of the enzyme (450 nm) when it is in the reduced state and complexed with carbon monoxide. Most CYPs require a protein partner to deliver one or more electrons to reduce the iron (and eventually molecular oxygen).

How do you memorize enzyme inhibitors?

Memorize Enzyme Inhibition – YouTube

What are CYP450 inducers and inhibitors?

The cytochrome P450 (CYP450) enzymes are essential to produce numerous agents, including cholesterol and steroids. They are also necessary for the detoxification of foreign chemicals and the metabolism of drugs. Drugs that cause CYP450 drug interactions are referred to as either inhibitors or inducers.

What are the 3 types of enzyme inhibitors?

Enzyme inhibition is an important means of regulating activity in living cells. There are three basic types of enzyme inhibition: competitive, noncompetitive, and uncompetitive.

What drugs are CYP2C19 inhibitors?

Strong inhibitors Weak inhibitors
CYP2C19 fluconazole(f), fluoxetine(g), fluvoxamine(a), ticlopidine(c) omeprazole
CYP2D6 bupropion, fluoxetine(g), paroxetine, quinidine(h), terbinafine amiodarone(h), celecoxib, cimetidine, clobazam, cobicistat, escitalopram, fluvoxamine(a), labetalol, sertraline, vemurafenib

What are strong CYP3A4 inhibitors?

Potent inhibitors of CYP3A4 include clarithromycin, erythromycin, diltiazem, itraconazole, ketoconazole, ritonavir, verapamil, goldenseal and grapefruit. Inducers of CYP3A4 include phenobarbital, phenytoin, rifampicin, St. John’s Wort and glucocorticoids.

Why cytochrome P450 is called so?

Cytochromes P450, a family of heme-containing monooxygenases that catalyze a diverse range of oxidative reactions, are so-called due to their maximum absorbance at 450 nm, ie, “Pigment–450 nm,” when bound to carbon monoxide.

Is alcohol an inducer or inhibitor of P450?

Ethanol is known to induce certain cytochrome P450 (CYP) enzymes, particularly the 2E1 isoform, which has been shown to metabolise arachidonic acid (AA) to the 19-hydroxy metabolite (19-HETE), which could have pro-hypertensive activity; CYP4A, by comparison, is the principal AA omega-hydroxylase in the liver.

How do you remember Vmax and Km?

Increasing the substrate will not overcome the inhibition, hence, Vmax decreases and hence, Km remains same.


  1. Vmax = Vertical (y-axis)
  2. Km = x-axis (‘k’ looks like ‘x’)
  3. Very efficient and Com(Km)petent, i.e. Vmax represent efficacy and Km represent competency.

What are the 2 types of inhibitors?

There are two types of inhibitors; competitive and noncompetitive inhibitors.

What are CYP2C19 inhibitors?

Drugs and compounds which inhibit or antagonize the biosynthesis or actions of CYTOCHROME P-450 CYP2C19. A selective serotonin-reuptake inhibitor used to treat obsessive-compulsive disorder.

What are enzyme 12 inhibitors?

The enzyme inhibitors are molecules which can bind to the enzyme and reduce the activity. There are three types of inhibition, competitive, non-competitive and feedback.

What are 2 types of enzyme inhibitors?

There are two types of inhibitors; competitive and noncompetitive inhibitors. Competitive inhibitors bind to the active site of the enzyme and prevent substrate from binding. They can be, however, dissociated with the addition of more substrates.

Is omeprazole an inhibitor CYP2C19?

Omeprazole is primarily converted by CYP2C19 to inactive metabolites. Omeprazole inhibits CYP2C19 and therefore its own metabolism. This leads to non-linear pharmacokinetics. The AUC response to dose increases is greater than linear in normal metabolizer patients at doses exceeding 40 mg.

Is omeprazole a CYP450 inhibitor?

Enzymes of the cytochrome P450 family play a key role in xenobiotic and thus drug metabolism. The H+,K(+)-ATPase blocker, omeprazole, has been reported to inhibit (subfamily P450IIC) or induce (P450IA) this system.

Is omeprazole a strong CYP3A4 inhibitor?

Six proton pump inhibitors (PPIs), omeprazole, lansoprazole, esomeprazole, dexlansoprazole, pantoprazole, and rabeprazole, were shown to be weak inhibitors of cytochromes P450 (CYP3A4, -2B6, -2D6, -2C9, -2C8, and -1A2) in human liver microsomes.

Is omeprazole a CYP3A4 inhibitor?

In vitro, omeprazole and its metabolites inhibit CYP3A4. In addition, both omeprazole and particularly esomeprazole can activate the pregnane X and aryl hydrocarbon receptors9, 10 and might, therefore, also induce CYP3A4 and CYP1A2 expression.

How many CYP450 enzymes are there?

There are more than 50 CYP450 enzymes, but the CYP1A2, CYP2C9, CYP2C19, CYP2D6, CYP3A4, and CYP3A5 enzymes metabolize 90 percent of drugs. These enzymes are predominantly expressed in the liver, but they also occur in the small intestine (reducing drug bioavailability), lungs, placenta, and kidneys.

What drugs are CYP450 inducers?

Inducers: carbamazepine, griseofulvin, phenobarbital, phenytoin, rifampin, St. John’s wort.

What is difference between inducer and inhibitor?

The key difference between enzyme inhibitor and enzyme inducer is that enzyme inhibitor decreases the activity of an enzyme by binding with the active site of the enzyme. In contrast, enzyme inducer increases the metabolic activity of an enzyme either by binding to it or by increasing the gene expression.

Is smoking an enzyme inducer or inhibitor?

Smoking is a potent inducer of CYP1A2 enzyme activity, resulting in significant lower clozapine serum concentrations in smokers compared with non-smokers, upon a given dose. Recently, a single nucleotide polymorphism identified at position 734 of the CYP1A2 gene, was reported to affect the inducibility of the enzyme.

What is the unit for Vmax?


The Vmax unit is moles/min, moles/sec, µmoles/min, or µmoles/sec. Vmax depends upon the amount or the concentration of the enzyme as well as the structure of the enzyme. Biology definition: Vmax is the maximum initial velocity or rate of a reaction.