Restarting Lamotrigine after abrupt Discontinuation.


(Q.1): Patient is stable on Lamotrigine but suddenly stopped it due to rash.

Lamotrigine can be restarted (without need for titration) within how many days of lamotrigine discontinuation?

 


 

If a patient has discontinued lamotrigine for a period of more than 5 half-lives, it is recommended that initial dosing recommendations and guidelines be followed.

 

What is the mean half life of lamotrigine in healthy volunteers (single and multiple doses) receiving lamotrigine monotherapy?

22.8 – 37.4 hr

 

Based on this information, 5 half-life = 114 – 187 hr (4.7 – 7.7 days).

 


Hence, patient can restart lamotrigine (without need for titration) within 4 days of medication discontinuation.



 

(Q.2): Patient is stable on Lamotrigine and Depakote but suddenly stopped lamotrigine due to rash.

Lamotrigine can be restarted (without need for titration) within how many days of lamotrigine discontinuation?

 


Depakote increases the half-life of lamotrigine to mean values of:

48.3 to 59 hours.

 

Based on this information, 5 half-life = 241.5 – 295 hr (10 – 12 days).

 


Hence, patient on depakote can restart lamotrigine (without need for titration) within 10 days of medication discontinuation.



Source:
  • Lamotrigine package insert. 
  • Clin Pharmacokinet. 1993 Dec;25(6):433-43.

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