Stahl's Essential Psychopharmacology Online
In Collaboration With
3,4-Diaminopyridine
Therapeutics
Brands
• Amifampridine
Generic?
Yes
Class
• Cholinergic agonist, potassium channel blocker, neuromuscular drug
Commonly Prescribed for
(FDA approved in bold)
• Lambert-Eaton myasthenic syndrome (LEMS)
• Congenital myasthenia gravis (CMG)
• Multiple sclerosis (MS)
How the Drug Works
• Potassium
channel blocker. Reduces flow of potassium across nerve terminal
membranes and increases calcium influx with prolongation
of action potential. This promotes
presynaptic release of acetylcholine and may improve weakness and
autonomic dysfunction
How Long Until It Works
• About 20 minutes, but maximum effect might take a few days
If It Works
• Continue
to use to reduce symptoms of LEMS or CMG at lowest required dose. In
LEMS, disease-modifying treatments, such as
plasma exchange, intravenous immune
globulin, corticosteroids, or immunosuppressives, are useful
• Identifying malignancy such as small-cell lung cancer is essential
If It Doesn't Work
• LEMS - Treat with immunologic therapy. Removal of neoplasm may improve symptoms
• CMG - Establish the type. Presynaptic forms may respond to 3, 4 diaminopyridine. Acetylcholinesterase inhibitors may improve
or worsen symptoms, depending on the disorder
Best Augmenting Combos for Partial Response or Treatment-Resistance
• May be combined with pyridostigmine, which increases the available amount of acetylcholine for receptor binding and may allow
reduction of dose
Tests
• Obtain baseline CBC, electrolytes, glucose, BUN, creatinine, liver function tests. Repeat monthly for 3 months, then every
6 months while on treatment