P450 inducers and inhibitors

P450 inducers = increase metabolism of drugs metabolised by cytochrome P450 and thus decrease drug effect
  • Carbamazepine 
  • Phenytoin 
  • Rifampicin 
  • Phenobarbital 
  • Tobacco 
  • Chronic alcohol 
  • St Johns Wort 

P450 inhibitors = decrease metabolism of drugs metabolised by cytochrome P450 and thus increase drug effect
  • Cardiac
    • Amiodarone 
    • Verapamil
    • Quinidine
  • Antibiotics
    • Ciprofloxacin
    • Erythromycin
    • Metronidazole
    • Trimethoprim
    • Isoniazid
  • Antifungals
    • Fluconazole
    • Terbafine
  • HIV antivirals
  • Antacids
    • Cimetidine
    • Omeprazole
  • Psychiatric drugs
    • TCA
    • SSRIs especially fluoxetine
    • Haloperidol
  • Others
    • Methadone
    • Grapefruit juice

Drugs metabolised by cytochrome P450 include:
  • Cardiac
    • Beta blockers
    • Angiotensin II blockers
    • Statins
  • Psychiatric drugs
    • TCA
    • SSRI
    • antipsychotics
  • Analgesics
    • Tramadol
    • Codeine
    • Ibuprofen
  • Antiepileptics
  • Other
    • Sildenafil
    • Warfarin
    • Donepezil
    • PPIs
    • Glipizide
    • Theophylline

Small print gem: the name cytochrome P450 comes from the fact the enzymes are inside the cell (cyto) and contain a haem pigment (chrome P) that absorbs light at a wavelength of 450nm when exposed to carbon monoxide

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Secret collector of interesting anonymised ECGs. Fan of the Bath Photomarathon. Lover of cream teas. [Sarah Hudson] (Your Picture)