Drug Groups

approved

Description

An optical isomer of quinine, extracted from the bark of the Cinchona tree and similar plant species. This alkaloid dampens the excitability of cardiac and skeletal muscles by blocking sodium and potassium currents across cellular membranes. It prolongs cellular action potential, and decreases automaticity. Quinidine also blocks muscarinic and alpha-adrenergic neurotransmission. [PubChem]

Indication

For the treatment of ventricular pre-excitation and cardiac dysrhythmias

Pharmacology

Quinidine, a hydantoin anticonvulsant, is used alone or with phenobarbital or other anticonvulsants to manage tonic-clonic seizures, psychomotor seizures, neuropathic pain syndromes including diabetic neuropathy, digitalis-induced cardiac arrhythmias, and cardiac arrhythmias associated with QT-interval prolongation.

Affected Organisms

Half Life

6-8 hours

Protein Binding

80-88%

Elimination

When the urine pH is less than 7, about 20% of administered quinidine appears unchanged in the urine, but this fraction drops to as little as 5% when the urine is more alkaline.

Distribution

* 2 to 3 L/kg
* 0.5 L/kg [congestive heart failure]
* 3 to 5 L/kg [cirrhosis of the liver]

Clearance

* 3 – 5 mL/min/kg [adults]

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