AED selection for patients taking antiretrovirals

Due to interactions, dose adjustments are often needed. This is a position paper with mostly level C recommendations. 

1.  If taking PTN, may need to increase lopinavir/ritonavir dosage up to 50 % to maintain levels
2.  Patients on VPA may need to reduce zidovudine dose to maintain zid. levels in serum
3.  Coadministration of VPA and efavirenz does not require dose adjustment of ef.
4.  Patients on ritonavir/ atazanavir may need 50 % lamotrigine dose increase to maintain LTG levels
5.  Coadministration of raltegravir/atazanavir and LTG may not require LTG dose adjustment
6.  Coadministration of raltegravir and midazolam may not require midazolam dose adjustment
7.  Counsel patients its unclear whether combinations of AED's and ARV's require dose adjustments esp enzyme inducers.  They may lead to virologic failure, esp protease inhibitors and nonnucleoside reverse transcriptase inhibitors

Combination AED therapy with Depakote and lamotrigine

Neurology 2012; 78: 62-68  Combing records of 148 disabled adults in state run institutions, authors analyzed whether any combination of AED's were superior to others.  Out of 32 AED combinations, only the combination of lamotrigine and valproate was superior to others,AND the addition of a third AED aggregately did not add to epileptic control over the use of two medicines