Lamotrigine is an important medication to remember. This was actually a primary reason why I started this blog. Here’s that case scenario from the past. Having a lack of understanding of lamotrigine and its adverse effects has led to patients being harmed and lawsuits against healthcare professionals. Here are some important practice pearls regarding lamotrigine.
Lamotrigine Rash
Lamotrigine carries a black box warning for the risk of serious and potentially life-threatening rashes, including Stevens-Johnson syndrome, toxic epidermal necrolysis, and DRESS. These reactions can involve blistering, peeling skin, mucous membrane involvement, fever, organ damage, and can be fatal.
Lamotrigine must be started at low doses and increased slowly because rapid dose escalation significantly raises the risk of serious, potentially life-threatening skin reactions—most notably Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN). Pay especially close attention to patients who have had changes in lamotrigine within the last 2-8 weeks as most of the concerns have arisen in that time frame.
When lamotrigine levels rise too quickly in the body, the immune system is more likely to react abnormally, leading to these severe rashes. The slow titration schedule allows the body to gradually adjust to the medication, dramatically reducing this risk. In fact, most severe skin reactions occur when the dose is started too high or increased too aggressively.
Lamotrigine Drug Interaction
Another reason for slow titration is that lamotrigine interacts with other medications—especially valproic acid (excellent one to remember for board exams). Valproic acid can more than double lamotrigine concentrations, making careful dose adjustments essential to avoid toxicity. Because of these risks, standard practice is to begin with very low doses and increase every one to two weeks according to established titration schedules.
Recommended Dosing
When patients aren’t taking an interacting medication, here is the standard dosing schedule;
Weeks 1 and 2: 25 mg once daily; increase based on response and tolerability as follows: Weeks 3 and 4: 50 mg/day in 1 to 2 divided doses based on chosen formulation; Week 5: 100 mg/day in 1 to 2 divided doses based on chosen formulation; Week 6: 200 mg/day in 1 to 2 divided doses based on chosen formulation (information from Uptodate and recommended maximum dose per manufacturer’s labeling)
When the patient is taking valproic acid, below is the appropriate dosing schedule;
Weeks 1 and 2: 25 mg every other day; increase based on response and tolerability as follows: Weeks 3 and 4: 25 mg once daily; Week 5: 50 mg/day in 1 to 2 divided doses based on chosen formulation; Week 6 and maintenance: 100 mg/day in 1 to 2 divided doses based on chosen formulation. (From Uptodate.com and Manufacturer recommendation)
Lamotrigine Lawsuits
There have been reported examples of medical lawsuits based upon the use of lamotrigine and the risk of Stevens-Johnson syndrome. Here are a couple of examples of case scenarios.
Missed Drug Side Effect Turns Toxic
Dosing Error Goes Unrecognized, Leading to Serious Patient Harm
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