Prajmaline

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Prajmaline
File:Prajmaline.svg
Systematic (IUPAC) name
(4α,16R,17R,21α)-4-propylajmalan-4-ium-17,21-diol
Identifiers
CAS Number 35080-11-6 N
ATC code C01BA08 (WHO)
PubChem CID: 37042
ChemSpider 16735977 YesY
UNII 75934UD4GJ YesY
Chemical data
Formula C23H33N2O2+
Molecular mass 369.520 g/mol
  • O[C@@H]6C4[C@@H]2C[C@]65c1ccccc1N(C)[C@H]5[C@@H]3C[C@H]4[C@H](CC)[C@@H](O)[N+]23CCC
  • InChI=1S/C23H33N2O2/c1-4-10-25-17-11-14(13(5-2)22(25)27)19-18(25)12-23(21(19)26)15-8-6-7-9-16(15)24(3)20(17)23/h6-9,13-14,17-22,26-27H,4-5,10-12H2,1-3H3/q+1/t13-,14-,17-,18-,19?,20-,21+,22+,23+,25?/m0/s1 YesY
  • Key:UAUHEPXILIZYCU-UUEXUKNBSA-N YesY
 NYesY (what is this?)  (verify)

Prajmaline (Neo-gilurythmal)[1] is a class Ia antiarrhythmic agent[2] which has been available since the 1970s.[3] Class Ia drugs increase the time one action potential lasts in the heart.[4] Prajmaline is a semi-synthetic propyl derivative of ajmaline, with a higher bioavailability than its predecessor.[5] It acts to stop arrhythmias of the heart through a frequency-dependent block of cardiac sodium channels.[2]

Mechanism

Prajmaline causes a resting block in the heart.[6] A resting block is the depression of a person's Vmax after a resting period. This effect is seen more in the atrium than the ventricle.[6] The effects of some Class I antiarrhythmics are only seen in a patient who has a normal heart rate (~1 Hz).[7] This is due to the effect of a phenomenon called reverse use dependence.[7] The higher the heart rate, the less effect Prajmaline will have.

Uses

The drug Prajmaline has been used to treat a number of cardiac disorders. These include: coronary artery disease,[8][9] angina,[8][9] paroxysmal tachycardia and Wolff–Parkinson–White syndrome.[1] Prajmaline has been indicated in the treatment of certain disorders where other antiarrhythmic drugs were not effective.[1]

Administration

Prajmaline can be administered orally,[9] parenterally[8] or intravenously.[8] Three days after the last dose, a limited effect has been observed. Therefore it has been suggested that treatment of arrhythmias with Prajmaline must be continuous to see acceptable results.[1]

Pharmacokinetics

The main metabolites of Prajmaline are: 21-carboxyprajmaline and hydroxyprajmaline. Twenty percent of the drug is excreted in the urine unchanged.

Daily therapeutic dose is 40–80 mg. Distribution half-life is 10 minutes. Plasma protein binding is 60%. Oral bioavailability is 80%. Elimination half-life is 6 hours. Volume of distribution is 4-5 L/kg. [3]

Side Effects

There are no significant adverse side-effects of Prajmaline when taken alone and with a proper dosage.[1][8][9] Patients who are taking other treatments for their symptoms (e.g. beta blockers and nifedipine) have developed minor transient conduction defects when given Prajmaline.[8]

Overdose

An overdose of Prajmaline is possible. The range of symptoms seen during a Prajmaline overdose include: no symptoms, nausea/vomiting, bradycardia, tachycardia, hypotension, and death.[3]

Other Potential Uses

Due to Prajmaline's sodium channel-blocking properties, it has been shown to protect rat white matter from anoxia (82 +/- 15%).[10][11] The concentration used causes little suppression of the preanoxic response.[10][11]

References

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