Lab Information Manual

Laboratory:

Clinical Biochemistry

Test Name:

TOPIRAMATE - (P) or (S)

Test Code: TOPI

Clinical Information:

Topiramate is a broad-spectrum antiseizure medication widely used for the treatment of focal and generalized epilepsies, Lennox-Gastaut syndrome, and migraine prophylaxis. It exerts its pharmacological effects through multiple mechanisms, including blockade of voltage-dependent sodium channels, enhancement of γ-aminobutyric acid (GABA)-mediated neurotransmission, inhibition of excitatory glutamate receptors, and weak inhibition of carbonic anhydrase activity. Topiramate demonstrates favorable pharmacokinetic characteristics, including high oral bioavailability, low protein binding, limited hepatic metabolism, and predominantly renal elimination.

Test Indications: TDM may assist in the evaluation of poor seizure control, suspected toxicity, assessment of medication adherence, optimization of dosing during pregnancy, management of patients with renal impairment, and interpretation of clinically significant drug interactions, particularly with enzyme-inducing antiseizure medications such as carbamazepine, phenytoin, and phenobarbital, which can increase topiramate clearance and reduce serum concentrations.

Collection Devices:

Preferred Device:

1 - Li Heparin, NO GEL 4.0 mL Tube(s) - Full Tube Collection