Correlation of Lamotrigine Concentrations Between Serum and Saliva

Abstract

There is a good correlation between salivary and serum concentrations for lamotrigine. However, there is wide interpatient variability in the saliva:serum ratio. The data suggest that salivary monitoring may play a role in the monitoring of lamotrigine for adult and pediatric patients.

Therapeutic Drug Monitoring of Classical and Newer Anticonvulsants

“…For salivary levels of drug to give meaningful information they must have some consistent relationship to the serum level. This appears to be the case for levetiracetam [153] and topiramate [154], but there is conflicting information for lamotrigine [155,156].…”

Therapeutic Drug Monitoring of Antiepileptic Medications

“…For drugs with active metabolites (e.g., oxcarbazepine, primidone), TDM can include measurement of the concentrations of both parent drug and its metabolite(s) or just of the metabolite(s). TDM of AEMs in saliva has not yet been widely applied (Liu & Delgado, 1999), but has been studied for ten drugs: carbamazepine (Ruiz et al, 2010;Tennison et al, 2004), gabapentin (Benetello et al, 1997;Berry et al, 2003), lamotrigine (Incecayir et al, 2007;Malone et al, 2006;Ryan et al, 2003), levetiracetam Guo et al, 2007;Mecarelli et al, 2007), oxcarbazepine (Cardot et al, 1995), phenobarbital (Tennison et al, 2004), phenytoin (Tennison et al, 2004), topiramate ), valproic acid (al Za'abi et al, 2003, and zonisamide (Kumagai et al, 1993). Of these ten drugs, gabapentin and valproic acid are clearly unsuited for salivary concentration analysis.…”

Monitoring salivary lamotrigine concentrations

“…14,15 The ratio between salivary and plasma concentrations of lamotrigine has been determined on several occasions, with mean values between 0.46 16 and 0.64. 9 There are at least two reports of the use of the salivary measurements in therapeutic drug monitoring. 7,9 However, in the study of Ryan et al 9 there was an uncomfortably wide range for the ratio between salivary and plasma concentrations of the drug in the population studied (0.41 to 1.26).…”

“…9 There are at least two reports of the use of the salivary measurements in therapeutic drug monitoring. 7,9 However, in the study of Ryan et al 9 there was an uncomfortably wide range for the ratio between salivary and plasma concentrations of the drug in the population studied (0.41 to 1.26). Even so, there was an overall correlation between the concentrations in the two fluids, and the authors of that report felt that salivary lamotrigine concentration monitoring could be useful in clinical practice.…”

“…However, in view of the relatively wide range of salivaryto-plasma lamotrigine concentration ratios described by Ryan et al, 9 it was thought desirable to first carry out some preliminary investigations on the validity of the salivary lamotrigine concentration monitoring approach under local conditions. The details of this investigation are described below.…”