Q:
What are 2 important P450s that exhibit polymorphisms?

A:
* P450 2D6
* P450 2C19

Q:
What are some of the drugs metabolised by P450 2D6?

A:
* Debrisoquine (antihypertensive)
* Propranolol (beta-adrenoreceptor antagonist)
* Codeine (narcotic)
* Thioridazine (antipsychotic tranquiliser)
* Imipramine (tricyclic antidepressant)

Q:
What is another term for P450 2D6?

A:
Debrisoquine hydroxylase.

Q:
What is another term for P450 2C19?

A:
S-mephenytoin hydroxylase.

Q:
What are some of the drugs metabolised by P450 2C19?

A:
* Mephenytoin (anticonvulsant)
* Omeprazole (proton pump inhibitor)
* Moclobemide (antidepressant)
* Proguanil (antimalarial)

Q:
True or false? More Asians than Caucasians have the 2D6 poor metaboliser phenotype.

A:
False. ~1% Asians vs ~7% Caucasians.

Q:
True or false? More Asians than Caucasians have the 2C19 poor metaboliser phenotype.

A:
True. ~20% Asians vs ~3% Caucasians.

Q:
What enzyme deficiency is present in defective drug acetylation?

A:
There is loss of N-acetyltransferase. Incidence of this poor metaboliser phenotype may be as high as 90% in middle-eastern races.