Q.11: Medications Affecting Lamotrigine Clearance ?

Q.11: Which of the following medication is NOT known to increase the apparent clearance of lamotrigine?

(a) Carbamazepine
(b) Estrogen-containing oral contraceptives
(c) Rifampin
(d) Valproate
(e) Phenobarbital

Answer –>(d) Valproate


Lamotrigine is metabolized predominantly by glucuronic acid conjugation, so medications that induce or inhibit glucuronidation may affect the apparent clearance of lamotrigine.

Medications that can INCREASE the apparent clearance of lamotrigine:

  • Carbamazepine
  • Phenytoin
  • Phenobarbital
  • Primidone
  • Estrogen-containing oral contraceptives
  • Rifampin 

Medications that can DECREASE the apparent clearance of lamotrigine:

  • Valproate (*)

Medications that will NOT AFFECT the apparent clearance of lamotrigine:

  • Gabapentin
  • Levetiracetam
  • Oxcarbazepine
  • Pregabalin
  • Topiramate
  • Felbamate

Also note that Lamotrigine have no effects on the pharmacokinetics of lithium.

Source: lamotrigine package insert.

Please do post your questions or comments below. 

Dr. Harvinder Singh, M.D. (Admin)

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