Cytochrome P450 1A2

Excerpt from Cafer's Mood Stabilizers and Antiepileptics

Cytochrome P450 1A2 (CYP1A2)

“One Axe to Grind; One Axe to Grow”

1A2 accounts for 10 - 15% of CYP activity in the liver. 52% of individuals are 1A2 ultrarapid metabolizers. Less than 1% are poor metabolizers.

inDucer = Down (Decreased substrate levels)

induction onsets and reverses slowly  = Delayed

inHibitor = High (Increased substrate levels)

inHibition happens within Hours = Hurried and reverses as soon as the inhibitor is cleared from the body (five half-lives of the inhibitor)

Here are the specific players in 1A2 interactions:

* Contraindicated with Luvox 

** Contraindicated with Luvox or Cipro 

Conclusion: Keep in mind that 52% of individuals have a 1A2 ultrarapid metabolizer genotype, and everyone who smokes has a rapid metabolizer phenotype.  The effect of smoking on olanzapine and clozapine is worthy of memorization. Memorization of other 1A2 substrates is of lower priority, as long as you remember to refer to this list whenever Luvox is in the mix. Run an interaction check on any medication regimen that includes Luvox. Try to keep Luvox out of the mix entirely—it is nonessential for treatment of OCD because other SSRIs are equally effective at high doses (page 99).

Wrap-up with mascots found throughout the book:

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