IMPORTANCE Agitation is common among patients with Alzheimer disease; safe, effective treatments are lacking. OBJECTIVE To assess the efficacy, safety, and tolerability of dextromethorphan hydrobromide-quinidine sulfate for Alzheimer disease-related agitation. DESIGN, SETTING, AND PARTICIPANTS Phase 2 randomized, multicenter, double-blind, placebo-controlled trial using a sequential paralle...

Opinion differs greatly about the value and risk of quinidine. The present communication attempts to demonstrate that more rational use of quinidine is possible by emphasis on serum quinidine concentration rather than on dose alone. Conversion of chronic atrial fibrillation and the appearance of myocardial toxicity are related more closely to the concentration of quinidine in the blood than to ...

The effect of the ouabain-quinidine interaction was examined in 10 conscious dogs. Left ventricular (LV) pressure, LV dP/dt, LV diameter and left atrial (LA) diameter were measured with high-fidelity micromanometers and sonomicrometer crystals. Ouabain, 0.025 mg/kg, significantly (p less than 0.05) increased LV dP/dt, LV and LA fractional shortening and LV and LA velocity of circumferential fib...

Intravenous injections of chloroquine terminated experimental atrial fibrillation in open chest dog preparations. Chloroquine and quinidine possess equal vasodilating properties when injected intra-arterially in the same dosage. Chloroquine and quinidine were equally effective in decreasing resting excitability of isolated cat papillary muscle; conduction velocity was markedly slowed by quinidi...

We studied the role of the anticholinergic properties of disopyramide and quinidine in mediating the electrophysiological effects of these agents on isolated cardiac tissue. In right atria, disopyramide, quinidine, and procainamide administered alone elicited negative chronotropic responses. However, after cholinergic stimulation with physostigmine (1 X 10" M), disopyramide and quinidine produc...

The effects of quinidine on the fast, the delayed, and the Ca2+-activated K+ outward currents, as well as on Na+ and Ca2+ inward currents, were studied at the soma membrane from neurons of the marine mollusk Aplysia californica. External quinidine blocks these current components but to different degrees. Its main effect is on the voltage-dependent, delayed K+ current, and it resembles the block...

We studied the role of the anticholinergic properties of disopyramide and quinidine in mediating the electrophysiological effects of these agents on isolated cardiac tissue. In right atria, disopyramide, quinidine, and procainamide administered alone elicited negative chronotropic responses. However, after cholinergic stimulation with physostigmine (1 X 10" M), disopyramide and quinidine produc...

Experiments were performed on awake dogs with chronic recording electrodes implanted on the SA node, His bundle, and right bundle branch. Quinidine at serum concentrations of 5 to 10 mg/ liter had little effect on AV conduction, but slowed conduction in Purkinje tissue, prolonged ventricular activation, decreased the excitability of atrium and ventricle, and prolonged the atrial refractory peri...

ATRIAL FIBRILLATION is a frequent, undesirable complication of mitral valvotomy in patients with sinus rhythm. The reported high incidence of this complication (23 to 50%) 1-7 has been the basis for advocating the prophylactic use of quinidine by Black and associates7 and Kittle and Crockett.3 Black and associates have reported reducing the postoperative incidence of atrial fibrillation from 42...

or quinidine. Two dose schedules were employed; procaine amide, 3.0 and 6.0 g daily and quinidine, 1.2 and 1.8 g daily. Though adequate and even high drug blood levels were reached, an effective antiarrhythmic response was observed in only eight patients receiving procaine amide and in seven of those taking quinidine. These modest successful results were associated with a high incidence of trou...