| Field Name |
Data Description |
| Test Name |
Lamotrigine (Lamictal), Serum |
| Code |
Lamotrigine Level., Lamictal. |
|
CPT Code |
80175 |
| Last Modified |
|
| Test Name |
Lamotrigin. |
| Synonyms |
TDM ,ROUTIN,LAMICT,LAMOTR |
| Patient Preparation |
|
| Spec. Requirements |
Blood |
| Tube |
Red, Drk Green, or Lavender(EDTA) Top |
| Collection Volume |
4.0 mL Red, 2.0 mL Lavender, or 4.0 Drk Green Top |
| Storage |
Ambient, Refrigerate, or Freeze 14 days |
| Routine TAT |
|
| STAT TAT |
N/A |
| Days Test Performed |
|
| Performed by BHS |
None |
| See Availability |
|
| Reference Lab |
LabCorp of America |
| Reference Lab Code |
716944 Lamotrigine (Lamictal), Serum |
| Clinical Use |
Lamotrigine is an antiepileptic drug (AED) of the phenyltriazine class that is chemically unrelated to existing AEDs. The precise mechanism of action is unknown although it has been postulated lamotrigine inhibits voltage-sensitive sodium channels thereby stabilizing neuronal membranes and consequently modulating presynaptic transmitter release of excitatory amino acids (eg, glutamate, aspartate). Lamotrigine is 55% bound to plasma proteins and is metabolized predominately to an inactive 2-N-glucuronide conjugate. Peak plasma concentration occurs at 1.4-4.8 hours following oral administration.[1] The elimination half-life varies from 12 to 70 hours. The longerhalf-lives are observed in patients on concomitant valproic acid therapy. Accordingly, if lamotrigine is co-administeredwith valproic acid, the dose of lamotrigine must be reduced to less than half the normal dosage. The most common adverse reactions are associated with the use of lamotrigine in combination with other anticonvulsants, and includes dizziness, diplopia, ataxia, blurred vision, nausea and vomiting, somnolence, headache, and rash. The anticonvulsants phenytoin, phenobarbital, primidone, andcarbamazepine can reduce lamotrigine levels when co- administered.[2] Conversely, lamotrigine can reduce levels of levetiracetam when co-administered.[3] In children, investigators[4] have found large differences in lamotrigineplasma levels in patients with improvement in seizure frequency, but patients who were seizure-free had higher lamotrigine levels than other patients in the study. |
| Reference Range |
|
| Critical Value |
|
|
|
| Testing Sample Type |
Serum or Plasma |
| Min Lab Testing Volume |
0.5 mL |
| Special Handling |
|
| Lab Notes |
|
| Methodology |
LC/MS-MS - Liquid Chromatography/Tandem Mass Spectrometry |
| Limitations |
Causes for Rejection: Gel-barrier tube |
|
