When do you recommend HLA testing prior to prescribing lamotrigine, carbamazepine, or oxcarbazepine to patients of Asian descent?

This is one of the few actionable tests to avoid the more frequent occurrence of DRESS (Drug Rash with Eosinophilia Syndrome) or SJS (Stevens-Johnson Syndrome). Practically speaking, it is unusual for clinicians to have these HLA tests available in a fashion timely enough to match the usual need for clinical decision making. Alternatively, other mood stabilizers can be used with less risk and more immediately. However, when time allows and the use of one of these three AEDs cannot be avoided, it...

I never use carbamazepine, given how it’s a pan-inducer and often lowers the level of other medications that may be in the regimen, such as quetiapine and haloperidol, since they are mainly metabolized by CYP3A4.

Oxcarbazepine has a 50% reduction in the induction of carbamazepine, so I use that sometimes.

Lamotrigine is better tolerated and works on the UGT pathway instead of CYP, so it doesn’t have as much interaction with other medications. If I were to use it in a patient of Asian descent, I wo...

I’ve never had a patient who needed this.