3,4-Diaminopyridine

freely soluble in water, and slightly soluble in solvents ethanol, methanol and acetic acid

12.2 [ug/mL] (The mean of the results at pH 7.4)

Breastfeeding; Lactation; Neuromuscular Agents; Potassium Channel Blockers;

FDA approved drugs -> Active ingredient

EMA approved medicines: Human medicine

Danger

H300 (94.2%): Fatal if swallowed [Danger Acute toxicity, oral]

P260, P261, P262, P264, P264+P265, P270, P271, P280, P284, P301+P316, P302+P352, P304+P340, P305+P351+P338, P316, P319, P320, P321, P330, P332+P317, P337+P317, P361+P364, P362+P364, P403+P233, P405, and P501 (click each P-code to see the statement)

Aggregated GHS information provided per 52 reports by companies from 10 notifications to the ECHA C&L Inventory. Each notification may be associated with multiple companies.

Amifampridine has had limited clinical use, but adverse events have been largely neurologic and gastrointestinal. Serum ALT elevations were not reported in the prelicensure studies of amifampridine but were reported as occurring in a small proportion of patients in safety reviews by the Food and Drug Administration. Nevertheless, there have been no reports of clinically apparent liver injury associated with its use. Thus, liver injury from amifampridine must be rare if it occurs at all.

Drug Induced Liver Injury Rank (DILIrank 2.0)

Amifampridine

vNo-DILI-concern

0

No match

DOI:10.1016/j.drudis.2016.02.015

N - Nervous system

QN - Nervous system

Administration of amifampridine to patients with LES in clinical trials resulted in improvement of the compound muscle action potential (CMAP), muscle function, and quantitative myasthenia gravis (QMG) score. One case of a slight prolongation of the QTc interval in male patient with LEMS and euthyroid Hashimoto’s disease treated with 90 mg of amifampridine in combination with 100 mg azathioprine was reported. _In vitro_, amifampridine was shown to modulate cardiac conduction and induce phasic contractions in different arteries from several species. In addition, it stimulated potassium-evoked dopamine and noradrenaline release in rat hippocampal slices and upregulate acetylcholine release in the brain. It may also potentiate adrenergic and cholinergic neuromuscular transmission in the gatrointestinal tract. In a single pharmacokinetic study, no effect was observed of amifampridine phosphate on cardiac repolarization as assessed using the QTc interval. There were no changes in heart rate, atrioventricular conduction or cardiac depolarization as measured by the heart rate, PR and QRS interval durations.

Amifampridine is a symptomatic treatment that increases acetylcholine concentrations at the neuromuscular junction. It selectively blocks presynaptic fast voltage-gated potassium channels, thereby prolonging cell membrane depolarization and action potential, and augmenting calcium transport into the nerve endings. Increased intracellular calcium enhances the exocytosis of acetylcholine-containing vesicles and enhances impulse transmission at central, autonomic, and neuromuscular synapses. Amifampridine improves muscle strength and resting compound muscle action potential (CMAP) amplitudes with an overall weighted mean difference of 1.69 mV.