Levetiracetam is a relatively new anti-epileptic drug licensed for refractory partial epilepsy, although it may have a broad range of action. Levetiracetam's mode of action is unknown.1 Common adverse effects reported relate to the central nervous system, but recognised gastrointestinal side effects include diarrhoea and anorexia.2 We report four cases of considerable weight loss associated with using levetiracetam (table).
Table 1.
Weight loss in patients taking levetiracetam
| Patient | Sex | Age (years) | Type of focal epilepsy | Daily dose of levetiracetam (mg) | Duration of treatment (months) | Weight loss (kg) | Other anti-epileptic treatment |
|---|---|---|---|---|---|---|---|
| 1 | Male | 20 | Symptomatic | 2000 | 6 | 20 | Carbamazepine |
| 2 | Female | 49 | Symptomatic | 2000 | 5 | 35 | Sodium valproate |
| 3 | Female | 30 | Symptomatic | 3000 | 6 | 25 | Lamotrigine, clonazepam |
| 4 | Female | 22 | Cryptogenic | 3000 | 12 | 27 | Lamotrigine, topiramate |
No change in anti-epileptic treatment was made during the period of treatment of the four patients, and we identified no other cause of weight loss. The patients lost 2.3-7.0 kg a month, and starting levetiracetam coincided with the start of the period of weight loss. One patient stopped the treatment, and her weight increased. The other three patients decided to continue treatment because levetiracetam had improved their control of seizures. Their weight stabilised or increased after reducing the dose of levetiracetam by 250-500 mg.
The mechanism of the weight loss is unclear. None of the patients reported decreased appetite during the period of weight loss; however, one patient developed pica and craved only toast, cereal, scallops, and caviar. All cases were reported to the Committee on Safety of Medicines and the manufacturers.
We have not found any other reported cases of weight loss associated with levetiracetam. We have about 300 patients who have been prescribed levetiracetam on our epilepsy unit database. These four cases therefore represent about 1% of patients on the drug, which, for a serious adverse effect, might reasonably be regarded as common. Anti-epileptic drugs known to cause considerable weight loss include topiramate and zonisamide.3,4 Levetiracetam is also a potential cause of weight loss.
Funding: None.
Competing interests: PS has received an unrestricted research grant from UCB Pharma, manufacturer of levetiracetam, and has received payments for speaking and hospitality from UCB Pharma, GlaxoSmithKline, and Novartis. TP and SH have received unrestricted educational grants from GlaxoSmithKline, manufacturer of lamotrigine.
References
- 1.Shorvon S. Handbook of epilepsy treatment. Oxford: Blackwell Science, 2000.
- 2.British Medical Association, Royal Pharmaceutical Society of Great Britain. British national formulary. London: BMA, RPS, 2003: 231-2. (No 45.)
- 3.Glanser TA. Topiramate. Epilepsia 1999;40(suppl 5): S71-80. [DOI] [PubMed] [Google Scholar]
- 4.Faught, Ayala R, Montowris GG, Leppik IE. Randomised controlled trial of zonisamide for the treatment of refractory partial-onset seizures. Neurology 2000;57: 1774-9. [DOI] [PubMed] [Google Scholar]