THE PHARMACOLOGY OF N-(4-METHOXYBENZYL)-ISOQUINOLINIUM CHLORIDE, WIN 2173, WITH PARTICULAR REFERENCE TO ITS CARDIAC EFFECTS

¹ Department of Pharmacology, Hahnemann Medical College and Hospital, Philadelphia, Pennsylvania

N-(4-methoxybenzyl)-isoquinolinium chloride is an aromatic quaternary ammonium compound which has weak ganglionic and neuromuscular blocking effects. Its main action is a positive inotropic and chronotropic effect on the heart which has been demonstrated in this investigation on isolated cat atrium, intact dogs and humans. These effects are more pronounced under conditions of hypothermia. Local anesthesia comparable to that obtainable by procaine is produced by intradermal injection. However, WIN 2173 produces a local reaction suggestive of histamine release.

Unlike quinidine and similar drugs, WIN 2173 does not protect against epinephrine-hydrocarbon induced arrhythmias. However, it is much more potent than quinidine in raising the threshold of electrically indluced atrial fibrillation in the cat.

The drug is well tolerated in intact unanesthetized animals and humans provided the dose does not exceed 5 mgm./kgm. intravenously or intramuscularly. Dilation of the pupils, flushing and occasionally vertigo are encountered in humans but are transient. The clinical trial for the cure of human arrhythmias will be the subject of a future report.