|Clinical Use:||Clinicians use the test for Lamotrigine for monitoring serum concentration of Lamotrigine, and for testing compliance. Serum concentration can be used to adjust Lamotrigine doses in patients receiving other anticonvulsant drugs which interact pharmacokinetically with Lamotrigine.|
|Background:||Lamotrigine is used for the treatment of bipolar I disorder and a wide variety of seizure disorders including Lennox-Gastaut syndrome, primary generalized tonic-clonic seizures, and partial seizures. It may also be used in the treatment of treatment of migraine, trigeminal neuralgia, and treatment-refractory depression. Lamotrigine inhibits glutamate release (an excitatory amino acid) and voltage-sensitive sodium channels to stabilize neuronal membranes; it also weakly inhibits the 5-HT3 (serotonin) receptor.
Lamotrigine oral bioavailability is very high (approximately 98%).The drug is metabolized by glucuronic acid conjugation to inactive metabolites. The half-life is 25 to 33 hours in adults, but decreases with concurrent use of phenytoin or carbamazepine (13-14 hours), and increases with concomitant valproic acid therapy (59-70 hours), renal dysfunction, or hepatic impairment. Common adverse effects are dizziness, ataxia, blurred or double vision, nausea or vomiting.
|Reference Ranges:||4 – 60 µmol/L|
|Patient Preparation:||None required|
|Specimen Requirements:||Serum (SST) sample|
|Turnaround Time:||1 week|
|Referred Test:||Referred test|
|Location:||Therapeutic Drug Monitoring Unit|