Lamotrigine and Decreased Appetite
No, lamotrigine does not cause decreased appetite and is actually associated with weight stability or modest weight loss rather than appetite suppression.
Evidence Summary
The available evidence consistently demonstrates that lamotrigine has minimal to no impact on appetite in both children and adults:
Pediatric Population
In children with epilepsy, lamotrigine has minimal impact on weight and appetite 1. A systematic review specifically categorized lamotrigine among the antiseizure medications that do NOT cause decreased appetite or weight loss 1. This contrasts sharply with medications like topiramate, fenfluramine, and zonisamide, which are robustly associated with appetite suppression.
A direct comparison study in children found that while topiramate caused poor appetite and weight loss, lamotrigine did not demonstrate these effects 2. The adverse event profile of lamotrigine in children was primarily limited to CNS effects (rash, headaches, sleep disturbances) rather than appetite-related issues 2.
Adult Population with Bipolar Disorder
In adults treated for bipolar disorder, lamotrigine demonstrates weight neutrality over extended treatment periods. An 18-month controlled trial showed mean weight change of -1.2 kg with lamotrigine versus +0.2 kg with placebo—a clinically insignificant difference 3. Only 12.1% of patients experienced ≥7% weight loss with lamotrigine compared to 11.5% with placebo, indicating no meaningful appetite suppression 3.
A comprehensive safety review of nearly 1800 patients with bipolar disorder treated with lamotrigine for up to 18 months found that lamotrigine was not associated with weight changes and had an adverse event profile comparable to placebo 4. Notably, headache was the most common adverse event—not appetite changes 4.
Clinical Context
When weight changes do occur with lamotrigine, they appear to be modest weight loss rather than appetite-driven effects 5. This distinguishes lamotrigine from medications like valproate (associated with weight gain in up to 50% of users) or topiramate (associated with significant appetite suppression) 5.
Clinical Implications
- If a patient reports decreased appetite while taking lamotrigine, investigate alternative causes rather than attributing it to the medication
- Lamotrigine can be considered a weight-neutral option when metabolic concerns are present
- The medication's tolerability profile makes it suitable for long-term maintenance therapy without appetite-related complications