U.S. Department of Health & Human Services Divider Arrow National Institutes of Health Divider Arrow NCATS

Details

Stereochemistry ACHIRAL
Molecular Formula C5H7N3.H3O4P
Molecular Weight 207.1244
Optical Activity NONE
Defined Stereocenters 0 / 0
E/Z Centers 0
Charge 0

SHOW SMILES / InChI
Structure of AMIFAMPRIDINE PHOSPHATE

SMILES

OP(O)(O)=O.NC1=CC=NC=C1N

InChI

InChIKey=KAICRBBQCRKMPO-UHFFFAOYSA-N
InChI=1S/C5H7N3.H3O4P/c6-4-1-2-8-3-5(4)7;1-5(2,3)4/h1-3H,7H2,(H2,6,8);(H3,1,2,3,4)

HIDE SMILES / InChI

Molecular Formula C5H7N3
Molecular Weight 109.1292
Charge 0
Count
Stereochemistry ACHIRAL
Additional Stereochemistry No
Defined Stereocenters 0 / 0
E/Z Centers 0
Optical Activity NONE

Molecular Formula H3O4P
Molecular Weight 97.9952
Charge 0
Count
Stereochemistry ACHIRAL
Additional Stereochemistry No
Defined Stereocenters 0 / 0
E/Z Centers 0
Optical Activity NONE

Amifampridine (Firdapse), currently approved in the European Union, is the first and only approved drug for the symptomatic treatment of Lambert-Eaton Myasthenic Syndrome (LEMS) in adults, a rare autoimmune disease with the primary symptoms of muscle weakness. In LEMS, the body’s own immune system attacks connections between nerves and muscles and disrupts the ability of nerve cells to send signals to muscle cells. Amifampridine blocks voltage-dependent potassium channels, thereby prolonging pre-synaptic cell membrane depolarization. Prolonging the action potential enhances the transport of calcium into the nerve ending. The resulting increase in intracellular calcium concentrations facilitates exocytosis of acetylcholine containing vesicles, which in turn enhances neuromuscular transmission. Amifampridine phosphate has been granted Orphan Drug Designation and Breakthrough Therapy designation by the FDA for the treatment of Lambert-Eaton Myasthenic Syndrome (LEMS).

CNS Activity

Curator's Comment: Amifampridine (3,4-DAP) displays toxicity largely due to blood-brain-barrier (BBB) penetration.

Approval Year

TargetsConditions

Conditions

ConditionModalityTargetsHighest PhaseProduct
Palliative
Firdapse

Approved Use

Symptomatic treatment of Lambert-Eaton myasthenic syndrome (LEMS) in adults.

Launch Date

2009
Cmax

Cmax

ValueDoseCo-administeredAnalytePopulation
59.1 ng/mL
20 mg single, oral
dose: 20 mg
route of administration: Oral
experiment type: SINGLE
co-administered:
AMIFAMPRIDINE plasma
Homo sapiens
population: HEALTHY
age: ADULT
sex: FEMALE / MALE
food status: FASTED
40.6 ng/mL
20 mg single, oral
dose: 20 mg
route of administration: Oral
experiment type: SINGLE
co-administered:
AMIFAMPRIDINE plasma
Homo sapiens
population: HEALTHY
age: ADULT
sex: FEMALE / MALE
food status: FED
189 ng/mL
20 mg single, oral
dose: 20 mg
route of administration: Oral
experiment type: SINGLE
co-administered:
3-N-ACETYL-AMIFAMPRIDINE plasma
Homo sapiens
population: HEALTHY
age: ADULT
sex: FEMALE / MALE
food status: FED
268 ng/mL
20 mg single, oral
dose: 20 mg
route of administration: Oral
experiment type: SINGLE
co-administered:
3-N-ACETYL-AMIFAMPRIDINE plasma
Homo sapiens
population: HEALTHY
age: ADULT
sex: FEMALE / MALE
food status: FASTED
AUC

AUC

ValueDoseCo-administeredAnalytePopulation
117 ng × h/mL
20 mg single, oral
dose: 20 mg
route of administration: Oral
experiment type: SINGLE
co-administered:
AMIFAMPRIDINE plasma
Homo sapiens
population: HEALTHY
age: ADULT
sex: FEMALE / MALE
food status: FASTED
109 ng × h/mL
20 mg single, oral
dose: 20 mg
route of administration: Oral
experiment type: SINGLE
co-administered:
AMIFAMPRIDINE plasma
Homo sapiens
population: HEALTHY
age: ADULT
sex: FEMALE / MALE
food status: FED
1220 ng × h/mL
20 mg single, oral
dose: 20 mg
route of administration: Oral
experiment type: SINGLE
co-administered:
3-N-ACETYL-AMIFAMPRIDINE plasma
Homo sapiens
population: HEALTHY
age: ADULT
sex: FEMALE / MALE
food status: FED
1444 ng × h/mL
20 mg single, oral
dose: 20 mg
route of administration: Oral
experiment type: SINGLE
co-administered:
3-N-ACETYL-AMIFAMPRIDINE plasma
Homo sapiens
population: HEALTHY
age: ADULT
sex: FEMALE / MALE
food status: FASTED
T1/2

T1/2

ValueDoseCo-administeredAnalytePopulation
2.5 h
20 mg single, oral
dose: 20 mg
route of administration: Oral
experiment type: SINGLE
co-administered:
AMIFAMPRIDINE plasma
Homo sapiens
population: HEALTHY
age: ADULT
sex: FEMALE / MALE
food status: FASTED
2.28 h
20 mg single, oral
dose: 20 mg
route of administration: Oral
experiment type: SINGLE
co-administered:
AMIFAMPRIDINE plasma
Homo sapiens
population: HEALTHY
age: ADULT
sex: FEMALE / MALE
food status: FED
4.03 h
20 mg single, oral
dose: 20 mg
route of administration: Oral
experiment type: SINGLE
co-administered:
3-N-ACETYL-AMIFAMPRIDINE plasma
Homo sapiens
population: HEALTHY
age: ADULT
sex: FEMALE / MALE
food status: FED
4.1 h
20 mg single, oral
dose: 20 mg
route of administration: Oral
experiment type: SINGLE
co-administered:
3-N-ACETYL-AMIFAMPRIDINE plasma
Homo sapiens
population: HEALTHY
age: ADULT
sex: FEMALE / MALE
food status: FASTED
Doses

Doses

DosePopulationAdverse events​
100 mg 1 times / day multiple, oral
Highest studied dose
Dose: 100 mg, 1 times / day
Route: oral
Route: multiple
Dose: 100 mg, 1 times / day
Sources:
unhealthy, adult
10 mg 3 times / day multiple, oral
Recommended
Dose: 10 mg, 3 times / day
Route: oral
Route: multiple
Dose: 10 mg, 3 times / day
Sources:
healthy, adult
n = 52
Health Status: healthy
Age Group: adult
Population Size: 52
Sources:
Other AEs: Paresthesia, Dysesthesia...
Other AEs:
Paresthesia (69%)
Dysesthesia (69%)
Oral dysesthesia (69%)
Abdominal pain (25%)
Upper abdominal pain (25%)
Dyspepsia (17%)
Dizziness (12%)
Nausea (10%)
Back pain (8%)
Hypoesthesia (6%)
Muscle spasms (6%)
Sources:
75 mg 1 times / day multiple, oral (typical)
Studied dose
Dose: 75 mg, 1 times / day
Route: oral
Route: multiple
Dose: 75 mg, 1 times / day
Sources:
unhealthy, adult
n = 162
Health Status: unhealthy
Age Group: adult
Sex: M+F
Population Size: 162
Sources:
Other AEs: Convulsion, Head titubation...
Other AEs:
Convulsion (0.6%)
Head titubation (0.6%)
Tremor (0.6%)
Unresponsive to stimuli (0.6%)
Small cell lung cancer (0.6%)
Metastases to central nervous system (0.6%)
Lung cancer metastatic (0.6%)
Pulmonary mass (0.6%)
Bradycardia (0.6%)
Pneumonia (0.6%)
Sources:
AEs

AEs

AESignificanceDosePopulation
Nausea 10%
10 mg 3 times / day multiple, oral
Recommended
Dose: 10 mg, 3 times / day
Route: oral
Route: multiple
Dose: 10 mg, 3 times / day
Sources:
healthy, adult
n = 52
Health Status: healthy
Age Group: adult
Population Size: 52
Sources:
Dizziness 12%
10 mg 3 times / day multiple, oral
Recommended
Dose: 10 mg, 3 times / day
Route: oral
Route: multiple
Dose: 10 mg, 3 times / day
Sources:
healthy, adult
n = 52
Health Status: healthy
Age Group: adult
Population Size: 52
Sources:
Dyspepsia 17%
10 mg 3 times / day multiple, oral
Recommended
Dose: 10 mg, 3 times / day
Route: oral
Route: multiple
Dose: 10 mg, 3 times / day
Sources:
healthy, adult
n = 52
Health Status: healthy
Age Group: adult
Population Size: 52
Sources:
Abdominal pain 25%
10 mg 3 times / day multiple, oral
Recommended
Dose: 10 mg, 3 times / day
Route: oral
Route: multiple
Dose: 10 mg, 3 times / day
Sources:
healthy, adult
n = 52
Health Status: healthy
Age Group: adult
Population Size: 52
Sources:
Upper abdominal pain 25%
10 mg 3 times / day multiple, oral
Recommended
Dose: 10 mg, 3 times / day
Route: oral
Route: multiple
Dose: 10 mg, 3 times / day
Sources:
healthy, adult
n = 52
Health Status: healthy
Age Group: adult
Population Size: 52
Sources:
Hypoesthesia 6%
10 mg 3 times / day multiple, oral
Recommended
Dose: 10 mg, 3 times / day
Route: oral
Route: multiple
Dose: 10 mg, 3 times / day
Sources:
healthy, adult
n = 52
Health Status: healthy
Age Group: adult
Population Size: 52
Sources:
Muscle spasms 6%
10 mg 3 times / day multiple, oral
Recommended
Dose: 10 mg, 3 times / day
Route: oral
Route: multiple
Dose: 10 mg, 3 times / day
Sources:
healthy, adult
n = 52
Health Status: healthy
Age Group: adult
Population Size: 52
Sources:
Dysesthesia 69%
10 mg 3 times / day multiple, oral
Recommended
Dose: 10 mg, 3 times / day
Route: oral
Route: multiple
Dose: 10 mg, 3 times / day
Sources:
healthy, adult
n = 52
Health Status: healthy
Age Group: adult
Population Size: 52
Sources:
Oral dysesthesia 69%
10 mg 3 times / day multiple, oral
Recommended
Dose: 10 mg, 3 times / day
Route: oral
Route: multiple
Dose: 10 mg, 3 times / day
Sources:
healthy, adult
n = 52
Health Status: healthy
Age Group: adult
Population Size: 52
Sources:
Paresthesia 69%
10 mg 3 times / day multiple, oral
Recommended
Dose: 10 mg, 3 times / day
Route: oral
Route: multiple
Dose: 10 mg, 3 times / day
Sources:
healthy, adult
n = 52
Health Status: healthy
Age Group: adult
Population Size: 52
Sources:
Back pain 8%
10 mg 3 times / day multiple, oral
Recommended
Dose: 10 mg, 3 times / day
Route: oral
Route: multiple
Dose: 10 mg, 3 times / day
Sources:
healthy, adult
n = 52
Health Status: healthy
Age Group: adult
Population Size: 52
Sources:
Bradycardia 0.6%
75 mg 1 times / day multiple, oral (typical)
Studied dose
Dose: 75 mg, 1 times / day
Route: oral
Route: multiple
Dose: 75 mg, 1 times / day
Sources:
unhealthy, adult
n = 162
Health Status: unhealthy
Age Group: adult
Sex: M+F
Population Size: 162
Sources:
Convulsion 0.6%
75 mg 1 times / day multiple, oral (typical)
Studied dose
Dose: 75 mg, 1 times / day
Route: oral
Route: multiple
Dose: 75 mg, 1 times / day
Sources:
unhealthy, adult
n = 162
Health Status: unhealthy
Age Group: adult
Sex: M+F
Population Size: 162
Sources:
Head titubation 0.6%
75 mg 1 times / day multiple, oral (typical)
Studied dose
Dose: 75 mg, 1 times / day
Route: oral
Route: multiple
Dose: 75 mg, 1 times / day
Sources:
unhealthy, adult
n = 162
Health Status: unhealthy
Age Group: adult
Sex: M+F
Population Size: 162
Sources:
Lung cancer metastatic 0.6%
75 mg 1 times / day multiple, oral (typical)
Studied dose
Dose: 75 mg, 1 times / day
Route: oral
Route: multiple
Dose: 75 mg, 1 times / day
Sources:
unhealthy, adult
n = 162
Health Status: unhealthy
Age Group: adult
Sex: M+F
Population Size: 162
Sources:
Metastases to central nervous system 0.6%
75 mg 1 times / day multiple, oral (typical)
Studied dose
Dose: 75 mg, 1 times / day
Route: oral
Route: multiple
Dose: 75 mg, 1 times / day
Sources:
unhealthy, adult
n = 162
Health Status: unhealthy
Age Group: adult
Sex: M+F
Population Size: 162
Sources:
Pneumonia 0.6%
75 mg 1 times / day multiple, oral (typical)
Studied dose
Dose: 75 mg, 1 times / day
Route: oral
Route: multiple
Dose: 75 mg, 1 times / day
Sources:
unhealthy, adult
n = 162
Health Status: unhealthy
Age Group: adult
Sex: M+F
Population Size: 162
Sources:
Pulmonary mass 0.6%
75 mg 1 times / day multiple, oral (typical)
Studied dose
Dose: 75 mg, 1 times / day
Route: oral
Route: multiple
Dose: 75 mg, 1 times / day
Sources:
unhealthy, adult
n = 162
Health Status: unhealthy
Age Group: adult
Sex: M+F
Population Size: 162
Sources:
Small cell lung cancer 0.6%
75 mg 1 times / day multiple, oral (typical)
Studied dose
Dose: 75 mg, 1 times / day
Route: oral
Route: multiple
Dose: 75 mg, 1 times / day
Sources:
unhealthy, adult
n = 162
Health Status: unhealthy
Age Group: adult
Sex: M+F
Population Size: 162
Sources:
Tremor 0.6%
75 mg 1 times / day multiple, oral (typical)
Studied dose
Dose: 75 mg, 1 times / day
Route: oral
Route: multiple
Dose: 75 mg, 1 times / day
Sources:
unhealthy, adult
n = 162
Health Status: unhealthy
Age Group: adult
Sex: M+F
Population Size: 162
Sources:
Unresponsive to stimuli 0.6%
75 mg 1 times / day multiple, oral (typical)
Studied dose
Dose: 75 mg, 1 times / day
Route: oral
Route: multiple
Dose: 75 mg, 1 times / day
Sources:
unhealthy, adult
n = 162
Health Status: unhealthy
Age Group: adult
Sex: M+F
Population Size: 162
Sources:
OverviewDrug as perpetrator​

Drug as perpetrator​

TargetModalityActivityMetaboliteClinical evidence
no [Inhibition 30 uM]
no
no
no
no
no
no
no
no
no
no
no
no
no
no
no
yes [IC50 490.9 uM]
yes [IC50 524.8 uM]
yes
yes
yes
Drug as victimTox targets
Sourcing

Sourcing

Vendor/AggregatorIDURL
PubMed

PubMed

TitleDatePubMed
Antagonism of botulinum toxin A-mediated muscle paralysis by 3, 4-diaminopyridine delivered via osmotic minipumps.
2000 Oct
Electrophysiological analysis of the neurotoxic action of a funnel-web spider toxin, delta-atracotoxin-HV1a, on insect voltage-gated Na+ channels.
2001 Feb
Neuromuscular monitoring in myasthenic syndrome.
2001 Jun
Action of Micrurus dumerilii carinicauda coral snake venom on the mammalian neuromuscular junction.
2002 Feb
Wheel-running exercise alters rat diaphragm action potentials and their regulation by K+ channels.
2003 Aug
3,4-DAP-evoked transmitter release in hippocampal slices of aged rats with impaired memory.
2003 Dec 15
Exacerbation of Lambert-Eaton myasthenic syndrome caused by an L-type Ca2+ channel antagonist.
2003 Jan
Treatment of downbeat nystagmus with 3,4-diaminopyridine: a placebo-controlled study.
2003 Jul 22
[Formulation and stability of hospital preparation of 3,4-diaminopyridine capsules].
2003 Nov
Lambert-eaton myasthenic syndrome: diagnosis and treatment.
2003 Sep
Dual effects of nitric oxide in the mouse forced swimming test: possible contribution of nitric oxide-mediated serotonin release and potassium channel modulation.
2004 Mar
Treatment for Lambert-Eaton myasthenic syndrome.
2005 Apr 18
NCAM 180 acting via a conserved C-terminal domain and MLCK is essential for effective transmission with repetitive stimulation.
2005 Jun 16
Cognitive deficits in aged rats correlate with levels of L-arginine, not with nNOS expression or 3,4-DAP-evoked transmitter release in the frontoparietal cortex.
2005 Mar
Taicatoxin inhibits the calcium-dependent slow motility of mammalian outer hair cells.
2005 May
Inotropic effects of the K+ channel blocker 3,4-diaminopyridine: differential responses of rat soleus and extensor digitorum longus.
2006 Dec
Potassium channel blockers in multiple sclerosis: neuronal Kv channels and effects of symptomatic treatment.
2006 Jul
[Pathophysiology and treatment of fatigue in multiple sclerosis].
2006 Mar
Altered diaphragm muscle action potentials in Zucker diabetic fatty (ZDF) rats.
2006 Sep 28
Childhood myasthenia: clinical subtypes and practical management.
2007 Aug
Myasthenia gravis and Lambert-Eaton myasthenic syndrome in the same patient.
2007 Jul
Onset dynamics of type A botulinum neurotoxin-induced paralysis.
2008 Jun
[A case of Lambert-Eaton myasthenic syndrome with small cell lung cancer, treated with 3,4-diaminopyridine].
2009 Jan
Skeletal muscle contraction-induced vasodilator complement production is dependent on stimulus and contraction frequency.
2009 Jul
3,4-diaminopyridine safety in clinical practice: an observational, retrospective cohort study.
2010 Jun
Patents

Sample Use Guides

Amifampridine (Firdapse) should be given in divided doses, three or four times a day. The recommended starting dose is 15 mg a day, which can be increased in 5 mg increments every 4 to 5 days, to a maximum of 60 mg per day. No single dose should exceed 20 mg. Tablets are to be taken with food. For oral use only.
Route of Administration: Oral
In Vitro Use Guide
In nerve terminal regions of axons in rat olfactory cortex in the presence of tetraethylammonium (TEA, 5 mM) and Cd2+ (100 uM), the K(+)-component was depressed by Amifampridine (3,4-DAP; 1 to 20 uM; IC50 2.0 +/- 0.4 uM).
Substance Class Chemical
Created
by admin
on Sat Dec 16 02:04:26 GMT 2023
Edited
by admin
on Sat Dec 16 02:04:26 GMT 2023
Record UNII
8HF8FIN815
Record Status Validated (UNII)
Record Version
  • Download
Name Type Language
AMIFAMPRIDINE PHOSPHATE
EMA EPAR   MART.   MI   USAN   WHO-DD  
USAN  
Official Name English
Amifampridine phosphate [WHO-DD]
Common Name English
3,4-DIAMINOPYRIDINE PHOSPHATE
Systematic Name English
AMIFAMPRIDINE PHOSPHATE [MI]
Common Name English
ZENAS
Brand Name English
3,4-DAPP
Code English
AMIFAMPRIDINE PHOSPHATE [MART.]
Common Name English
FIRDAPSE
Brand Name English
AMIFAMPRIDINE PHOSPHATE [EMA EPAR]
Common Name English
AMIFAMPRIDINE PHOSPHATE [USAN]
Common Name English
AMIFAMPRIDINE PHOSPHATE [ORANGE BOOK]
Common Name English
DAPP
Code English
3,4-PYRIDINEDIAMINE, PHOSPHATE (1:1)
Systematic Name English
Classification Tree Code System Code
EMA ASSESSMENT REPORTS FIRDAPSE (AUTHORIZED: LAMBERT-EATON MYASTHENIC SYNDROME)
Created by admin on Sat Dec 16 02:04:26 GMT 2023 , Edited by admin on Sat Dec 16 02:04:26 GMT 2023
FDA ORPHAN DRUG 464814
Created by admin on Sat Dec 16 02:04:26 GMT 2023 , Edited by admin on Sat Dec 16 02:04:26 GMT 2023
NCI_THESAURUS C93038
Created by admin on Sat Dec 16 02:04:26 GMT 2023 , Edited by admin on Sat Dec 16 02:04:26 GMT 2023
FDA ORPHAN DRUG 534916
Created by admin on Sat Dec 16 02:04:26 GMT 2023 , Edited by admin on Sat Dec 16 02:04:26 GMT 2023
EU-Orphan Drug EU/3/02/124
Created by admin on Sat Dec 16 02:04:26 GMT 2023 , Edited by admin on Sat Dec 16 02:04:26 GMT 2023
FDA ORPHAN DRUG 295309
Created by admin on Sat Dec 16 02:04:26 GMT 2023 , Edited by admin on Sat Dec 16 02:04:26 GMT 2023
Code System Code Type Description
DRUG BANK
DBSALT002818
Created by admin on Sat Dec 16 02:04:26 GMT 2023 , Edited by admin on Sat Dec 16 02:04:26 GMT 2023
PRIMARY
FDA UNII
8HF8FIN815
Created by admin on Sat Dec 16 02:04:26 GMT 2023 , Edited by admin on Sat Dec 16 02:04:26 GMT 2023
PRIMARY
EVMPD
SUB30951
Created by admin on Sat Dec 16 02:04:26 GMT 2023 , Edited by admin on Sat Dec 16 02:04:26 GMT 2023
PRIMARY
RXCUI
2106337
Created by admin on Sat Dec 16 02:04:26 GMT 2023 , Edited by admin on Sat Dec 16 02:04:26 GMT 2023
PRIMARY
EPA CompTox
DTXSID40196254
Created by admin on Sat Dec 16 02:04:26 GMT 2023 , Edited by admin on Sat Dec 16 02:04:26 GMT 2023
PRIMARY
SMS_ID
100000115908
Created by admin on Sat Dec 16 02:04:26 GMT 2023 , Edited by admin on Sat Dec 16 02:04:26 GMT 2023
PRIMARY
NCI_THESAURUS
C142921
Created by admin on Sat Dec 16 02:04:26 GMT 2023 , Edited by admin on Sat Dec 16 02:04:26 GMT 2023
PRIMARY
MERCK INDEX
m1668
Created by admin on Sat Dec 16 02:04:26 GMT 2023 , Edited by admin on Sat Dec 16 02:04:26 GMT 2023
PRIMARY Merck Index
DAILYMED
8HF8FIN815
Created by admin on Sat Dec 16 02:04:26 GMT 2023 , Edited by admin on Sat Dec 16 02:04:26 GMT 2023
PRIMARY
PUBCHEM
9920716
Created by admin on Sat Dec 16 02:04:26 GMT 2023 , Edited by admin on Sat Dec 16 02:04:26 GMT 2023
PRIMARY
CAS
446254-47-3
Created by admin on Sat Dec 16 02:04:26 GMT 2023 , Edited by admin on Sat Dec 16 02:04:26 GMT 2023
PRIMARY
USAN
BC-58
Created by admin on Sat Dec 16 02:04:26 GMT 2023 , Edited by admin on Sat Dec 16 02:04:26 GMT 2023
PRIMARY
ChEMBL
CHEMBL354077
Created by admin on Sat Dec 16 02:04:26 GMT 2023 , Edited by admin on Sat Dec 16 02:04:26 GMT 2023
PRIMARY
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