Wallach's Interpretation of Diagnostic Tests: Pathways to Arriving at a Clinical Diagnosis (709 page)

   Definition

   A compound used to prevent or treat seizures

   Classic agents: carbamazepine (Tegretol), phenobarbital (Luminal), phenytoin (Dilantin), ethosuximide (Zarontin), valproic acid (Depakene, Depakote). Newer agents gabapentin (Neurontin), lamotrigine (Lamictal), oxcarbazepine (Trileptal), vigabatrin (Sabril), topiramate (Topamax), zonisamide (Zonegran)

   Use

   Treatment of seizure disorders

   
Normal therapeutic levels:
see Table 16.7

   Limitations

   Phenobarbital may be detected by immunoassay-based screening tests for barbiturates in urine and serum.

   Immunoassay tests are available for semiquantitative analysis in serum of topiramate, valproic acid, phenytoin, phenobarbital (may demonstrate significant cross-reactivity with other barbiturates), and zonisamide.

   Lamotrigine, breakdown products or artifacts of topiramate, carbamazepine, 10-OH-carbazepine, and phenytoin may be detected in general drug screens in urine or serum that utilize alkaline or weakly acidic liquid- or solid-phase extractions followed by gas chromatography or GC/MS analysis.

TABLE 16–7. Normal Therapeutic Levels of Anticonvulsants

*Submitted By Amanda J. Jenkins, PhD.

   For the majority of anticonvulsants, specific tests are required.

ANTIDEPRESSANTS
*

   Definition