Pharm: P 450

P 450 Cytochrome:

Hepatic metabolism involves the activity of a very large class of enzymes– the P 450 Cytochrome. This enzyme helps to break down drugs. Some of the Drugs that P 450 break down are

  • Digoxin
  • Warfarin
  • Estrogen
  • Phenytoin
  • Theophylline

A simple mnemonic is D.W.E.P.T

Look above, you should be able to figure that mnemonic out: if not here it is.

  • D = Digoxin
  • W = Warfarin
  • E = Estrogen
  • P = Phenytoin
  • T = Theophylline

As you can see DWEPT Drugs are some very important drugs. Take Digoxin, for example, this medication is used to treat mild to moderate Heart failure, it helps the heart to beat stronger. It does have other uses but, I am just making a point it is an important drug.

Now, what if that drug is altered in any way while in use by the patient meaning, the doctor decides to add an inducer or an inhibitor to the patient’s medication regimen, would this place the patient at an increased risk for complications?

An Inducer does what:

An Inducer encourages the breakdown (metabolism) of DWEPT Drugs. In other words, it speeds up the breakdown of:

  • Digoxin
  • Warfarin
  • Estrogen
  • Phenytoin
  • Theophylline

If any of these DWEPT drugs are combined with These Inducer Drugs:

  • Griseofulvin
  • Rifampin
  • Alcohol
  • Barbituates
  • Quinidine
  • Tetracycline
  • Carbamazepine
  • Sulfur

The amount of DWEPT drugs in the Body will be reduced.

An Inhibitor does What:

An Inhibitor slows down (or stops) the breakdown of DWEPT Drugs, because of the excess Drug in the body, this may lead to DWEPT TOXICITY.



  • Spiralactone
  • Macrolide
  • Cimetidine
  • Ketoconozole
  • Quinolone
  • INH
  • Dapsone
  • Proton Inhibitor
  • Grapefruit Juice/Ginger


Today’s notes from Pharm. P 450 Cytochrome, thank you for stopping. 

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