Adding valproic acid to lamotrigine.
| || |
- Lamotrigine is principally metabolised by UDP-glucuronosyltransferases.
| || |
- Valproic acid is principally metabolized by CYP2C9, CYP2C19, CYP2A6 and UDP-glucuronosyltransferases. Valproic acid is an inhibitor of the enzymes CYP2C9, epoxide-hydroxylase and UDP-glucuronosyltransferases.
- This combination of drugs may have possible synergistic effects. However, the pharmacokinetic drug interactions will influence the plasma levels. Dose adaptation will be recommended for this combination.
Start valproic acid
- Reduce the lamotrigine dose by 50% of the general dose when combined with valproate. Start valproate at low dose and increase dose based on serum concentration slowly.  
Stop valproic acid
- Valproate can increase lamotrigine plasma levels significantly by inhibiting lamotrigine’s glucuronidation. This effect of valproate is dose-dependent.
- Very slow titration of lamotrigine is recommended because reports of lamotrigine-related skin rashes. 
- ↑ 1.0 1.1 Farmacotherapeutisch Kompas; Toxicologie (dutch)
- ↑ 2.0 2.1 Farmacotherapeutisch Kompas - lamotrigine (dutch)
Cite error: Invalid
<ref> tag; name "ftk" defined multiple times with different content
- ↑ Drugs.com lamotrigine
- ↑ KNMP; Informatorium Medicamentorum 2015; Monografie "valproaat" (Dutch)
- ↑ Schalekamp T. et al, Interacties met Psychofarmaca, Stichting Health Base, Houten, 2002.
- ↑ Pisani at al, Interaction of lamotrigine with sodium valproate. Lancet. 1993 May 8;341(8854):1224.
- ↑ Bazire S, Psychotropic Drug Directory 2007, HealthComm UK Limited, Aberdeen, 2007.
- ↑ Chang CC at al, Toxic epidermal necrolysis with combination lamotrigine and valproate in bipolar disorder. Prog Neuropsych. Biol Psychiatry. 2006 Jan;30(1):147-50
The editors of psychiatrienet.nl take the greatest care to provide up-to-date and accurate information on this site. Nevertheless, mistakes and omissions cannot be entirely excluded. No rights devolve from the information provided. The editors and other providers of information to this site accept no responsibility for the content of this site or for the information provided therein; neither do they accept responsibility for possible damages which may derive from the use of the information on this site or from the linked sites. The editorial board accepts no responsibility for the content of the (linked) sites, for access to them, or for the products and services on these sites, nor for the occurrence of errors, viruses, and/or disruptions in service.