Update on treatment options for Lambert-Eaton myasthenic syndrome: focus on use of amifampridine.

Article Details

Citation

Lindquist S, Stangel M

Update on treatment options for Lambert-Eaton myasthenic syndrome: focus on use of amifampridine.

Neuropsychiatr Dis Treat. 2011;7:341-9. doi: 10.2147/NDT.S10464. Epub 2011 May 30.

PubMed ID
21822385 [ View in PubMed
]
Abstract

In Lambert-Eaton myasthenic syndrome (LEMS), antibodies against presynaptic voltage-gated calcium channels reduce the quantal release of acetylcholine, causing muscle weakness and autonomic dysfunction. More than half of the affected patients have associated small cell lung cancer, and thorough screening for an underlying malignancy is crucial. The mainstay of treatment for LEMS is symptomatic but immunotherapy is needed in more severely affected patients. Symptomatic therapies aim at increasing the concentration of acetylcholine at the muscle endplate. While acetylcholinesterase inhibitors were the first drugs to be used for the amelioration of symptoms, 3,4-diaminopyridine (3,4-DAP, amifampridine) has been shown to be more effective. 3,4-DAP blocks presynaptic potassium channels, thereby prolonging the action potential and increasing presynaptic calcium concentrations. This then results in increased quantal release of acetylcholine. The efficacy of 3,4-DAP for increasing muscle strength and resting compound muscle action potentials has been demonstrated by four placebo-controlled trials. Side effects are usually mild, and the most frequently reported are paresthesias. The most common serious adverse events are epileptic seizures. 3,4-DAP is currently the treatment of choice in patients with Lambert-Eaton myasthenic syndrome.

DrugBank Data that Cites this Article

Drugs
Drug Targets
DrugTargetKindOrganismPharmacological ActionActions
AmifampridinePotassium voltage-gated channel subfamily A member 1ProteinHumans
Yes
Blocker
Details
Drug Reactions
Reaction
Details
Drug Interactions
DrugsInteraction
Amifampridine
Cyclosporine
The risk or severity of seizure can be increased when Cyclosporine is combined with Amifampridine.
Amifampridine
Amphetamine
The risk or severity of seizure can be increased when Amphetamine is combined with Amifampridine.
Amifampridine
Tramadol
The risk or severity of seizure can be increased when Tramadol is combined with Amifampridine.
Amifampridine
Enflurane
The risk or severity of seizure can be increased when Enflurane is combined with Amifampridine.
Amifampridine
Theophylline
The risk or severity of seizure can be increased when Theophylline is combined with Amifampridine.