PDA p450 final
Terms
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- Probe(s) for CYP1A2
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Caffeine
Induced by smoking, charbroiled foods - Probe(s) for CYP2C9
- (S) warfarin
- Probe(s) for CYP2C19
- Omeprazole
- Probe(s) for CYP2D6
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Debrisoquine
Dextromethorphan
Inhibitor: quinidine
Codeine and Sparteine also metabolized by CYP2D6 - Probe(s) for CYP2E1
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Chloroxazone
St. John's Wart and Rifampin are inducers - Probe(s) for CYP3A4
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Erythromycin
Midazolam
Phenytoin and refampin are inducers - Drug X is metabolized from an inactive prodrug to the active X form by an enzyme. How will the D-R curve of Drug X shift if an inducer of the enzyme is given?
- Left
- Drug X is metabolized from an inactive prodrug to the active X form by an enzyme. How will the D-R curve of Drug X shift if an inhibitor of the enzyme is given?
- Right
- Drug X is an active parent compound that is metabolized to inactive metabolites by an enzyme. How will the D-R curve of Drug X shift if an inducer of the enzyme is given?
- Right
- Drug X is an active parent compound that is metabolized to inactive metabolites by an enzyme. How will the D-R curve of Drug X shift if an inhibitor of the enzyme is given?
- Left
- Ethanol, acetaminophen, and chlorzoxazone are substrates for which CYP isozyme?
- CYPE2A
- What changes take place in the elderly relative to creatinine?
- decreased creatinine clearance
- What areas of the body metabolize orally administered drugs vs. IV administered drugs?
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Oral - liver/small intestine
IV - liver only - Chronic alcohol and tobacco use have what effect on CYP450?
- Induction of CYP2E1
- What CYP450 metabolizes APAP to toxic intermediate?
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CYP2E1
Induced by alcohol - Characteristics of isozyme CYP1A2
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Metabolizes about 3% of drugs, including caffeine, R-warfarin.
Activity can be induced by smoking, chronic alcohol use, charbroiled foods, rifampin.
Activity can be inhibited by omeprazole, fluvoxamine - Characteristics of isozyme CYP2C9
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Metabolizes NSAIDS, S-warfarin, phenytoin, tolbutamide.
Induced by rifampin, carbazepine, ethanol.
Inhibited by Amiodarone, fluvastatin, fluconazole.
Altered genes: decreased activity in 1-3% whites and 2% blacks - Characteristics of isozyme CYP2C19
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Metabolizes benzodiazepines, tricyclic antidepressants, omeprazole, citalopram.
Induced by rifampin.
Inhibited by fluvoxamine, fluoxetine, and ticlopidine.
Altered genes: decreased or lack of activity in 2-5% whites, 15-20% asians - Characteristics of isozyme CYP2D6
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2-6% of total liver CYP450
Metabolizes almost 25% of drugs
NO INDUCERS
Inhibited by quinidine and fluoxetine
Genetic modifications: decreased in 5-10% whites, 1-3% chinese/black - Characteristics of isozyme CYP2E1
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Metabolizes ~1% of drugs
Activates and inactivates toxins
Metabolizes mainly small organic molecules (e.g. ethanol, carbon tetrachloride)
Numerous inducers/inhibitors.
Inhibitors block formation of toxic intermediates, i.e. APAP - Characteristics of isozyme CYP3A4
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Major form in liver and intestines
Metabolizes ~50% of drugs
Most first-pass metabolism
Responsible for most drug interactions
Induced by glucocorticoids, rifampin, carbamazepine, phenobarbitol, phenytoin
Inhibited by macrolide antibiotics, azole antifungals, grapefruit juice - What are major CYP3A4 substrates?
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Amiodarone
Amlodipine/felodipine (CCB)
Amprenavir/fosamprenavir
Aprepitant
Aripiprazole
Atazanavir
Benzphetamine
Bisoprolol
Bortezomib
Bosentan
Bromocriptine
Budesonide
Buprenorphine
Buspirone
Busulfan
Carbamazepine
Chloroquine
Chlorpheniramine
Cilostazole
Citalopram/Escitalopram
Clarithromycin
Cocaine
Colchicine
Conivaptan
Cyclophosphamide (activated)
Cyclosporine
Dantrolene
Dapsone
Delavirdine (NNRTI)
Diltiazem (CCB)
Disopyramide
Doxetaxel
Dexepin
Doxycycline
Doxorubicin
Efavirenz (NNRTI)
Eltriptan
Enalapril
Eplerenone
Ergot derivatives
Erythromycin
Estrogens (contraceptives)
Ethosuximide
Etoposide
Exemestane
Felbamate
Fentanyl
Flutamide
Fluticasone
Gefitinib
Haloperidol
Ifosfamide
Imatinib
Indinavir (PI)
Irinotecan
Isosorbide derivatives
Isradipine (CCB)
Itraconazole
Ketamine
Ketoconazole
Lansoprazole
Lidocaine
Losartan
Mefloqine
Methadone
Miconazole
Miglustat
Mirtazapine
Modafinil
Montelukast
Moricizine
Nateglinide (DM)
Nefazodone
Nelfinavir (PI)
Nevirapine (NNRTI)
Nicardipine (CCB)
Nifedipine (CCB)
Nimodipine (CCB)
Nisoldipiine (CCB)
Odansetron
Paclitaxel
Pergolide
Pimozide
Primaquine (antiprotazoal)
Quetiapine
Quinidine
Rabeprazole (PPI - with 2C19, which metabolizes all others)
Ranolazine
Repaglinide
Rifabutin
Ritonavir (PI)
Salmeterol
Saquinavir (PI)
Sildenafil/Vardenafil (Levitra/Viagra)
Sirolimus
Sunitinib
Tacrolimus
Tamoxifen
Tamsulosin
Telithromycin
Tetracycline
Theophylline
Tiagabine (anticonvulsant)
Ticlopidine (platelet inhibitor)
Trazodone
Trimethoprim
Trimipramine (TCA)
Troleandomycin
Venlafaxine
Verapamil (CCB)
Vinblastine/vincristine
Vinorelbine
Zolpidem
Zonisamide
Zopiclone
Statins *except* pravastatin
All benzos *except* lorazepam, lormetzepam, oxazepam, metaclazepam, nitrazepam, pinazepam, and temazepam. - What are common CYP450 3A4 inhibitors?
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Amiodarone
Clarithromycin
Cyclosporine
Danazol
Delavirdine
Diltiazem
Erythromycin
Fluoxetine
Fluvoxamine
Grapefruit juice
Indinavir
Itravonazole
Ketovonazole
Miconazole
Nefazodone
Nelfinavir
Nicardipine
Nifedipine
Pimozide
Propoxyphene
Quinidine
Ritonavir
Saquinavir
Sildenafil
Tacrolimus
Tamoxifen
Testosterone
Troleandomycin
Verapamil
Zafirlukast