Levetiracetam for Cramps, Spasticity and Neuroprotection in Motor Neuron Disease

Cramps in MNDs are believed to occur as a result of high-frequency burst firing of alpha motor neurons. Levetiracetam inhibits burst firing in epileptic rat hippocampus. Levetiracetam has never been tested against cramps in humans; however, it has helped another condition believed to result from burst firing of a motor nerve: hemi-facial spasm.

The mechanisms underlying spasticity in MNDs likely involve imbalance between excitatory and inhibitory influences on the alpha motor neurons. Levetiracetam may modulate these influences in a number of ways, including reducing the effects of zinc and beta-carbolines in GABA and glycine receptors. Levetiracetam reduces phasic (but not tonic) spasticity in patients with multiple-sclerosis.

Levetiracetam may have neuroprotective properties. In a model of cerebral ischemia induced by occlusion of the rat internal carotid artery, pre-treatment with levetiracetam reduced infarct size in a dose-dependent manner. In rats injected with kainic acid to induce calcium overload, oxidative stress and neurotoxicity, pretreatment with levetiracetam offset kainic acid's effects. The mechanisms for these effects may relate to levetiracetam's ability to influence calcium currents, or its ability to increase the release of growth factors from astrocytes, mechanisms that would be relevant in MNDs. Levetiracetam's ability to inhibit histone deacetylase may also help slow MNDs progression.

OBJECTIVES: 1. Assess the safety and tolerability of levetiracetam over 9 months in patients with MNDs. 2. Determine whether treatment with levetiracetam is associated with a reduction in cramps, spasticity or motor neuron disease progression.

METHODS:Open-label, Phase 2 trial of 20 adult patients with MNDs (ALS, PLS or PMA) at Duke University ALS Clinic. Eligible patients have cramps with average severity 50/100 points, are able to provide informed consent, have normal renal functions and are on a stable riluzole dose. Exclusions include pregnancy, unstable mental illness, dementia, drug abuse or non-compliance. The first 3 months of the study are a baseline period. Over the remaining 9 months, patients take levetiracetam at increasing doses up to 3000mg per day. Outcome measures include adverse events, tolerability,cramp-pain-severity score, cramp-frequency score, modified Ashworth Spasticity Score, Penn Spasm Score, FVC, ALSFRS-R and MMT.

Inclusion criteria

• Patients with MNDs (ALS, PLS or PMA)who have cramps with average severity 50/100 points, are able to provide informed consent, have normal renal function and are on a stable riluzole dose.

Exclusion criteria

• Pregnancy; unstable medical illness, dementia; drug abuse or non-compliance