Disopyramide arrhythmia with

All antiarrhythmic dra are used cautiously in patients with renal or hepatic disease. When renal or hepatic dysfunction is present, a dosage reduction may be necessary. All patients should be observed for renal and hepatic dysfunction. Quinidine and procainamide are used cautiously in patients with CHF. Disopyramide is used cautiously in patients with CHF, myasthenia gravis, or glaucoma, and in men with prostate enlargement. Bretylium is used cautiously in patients with digitalis toxicity because the initial release of norepinephrine with digitalis toxicity may exacerbate arrhythmias and symptoms of toxicity. Verapamil is used cautiously in patients with a history of serious ventricular arrhythmias or CHF. Electrolyte disturbances such as hypokalemia, hyperkalemia, or hypomagnesemia may alter the effects of the antiarrhythmic dru . Electrolytes are monitored frequently and imbalances corrected as soon as possible... 

Concurrent antiarrhythmic agents Concurrent antiarrhythmic agents may produce enhanced prolongation of conduction or depression of contractility and hypotension, especially in patients with cardiac decompensation. Reserve concurrent use of procainamide with other Class lA antiarrhythmic agents (eg, quinidine, disopyramide) for patients with serious arrhythmias unresponsive to a single drug and use only if close observation is possible. 

The applicability of the CAST results to other populations (eg, those without recent Ml) is uncertain. Considering the known proarrhythmic properties of disopyramide and the lack of evidence of improved survival for any antiarrhythmic drug in patients without life-threatening arrhythmias, the use of disopyramide as well as other antiarrhythmic agents should be reserved for patients with life-threatening ventricular arrhythmias. 

Concomitant antiarrhythmic therapy Reserve concomitant use of disopyramide with other class lA antiarrhythmics or propranolol for life-threatening arrhythmias unresponsive to a single agent. Such use may produce serious negative inotropic effects or may excessively prolong conduction, particularly with cardiac decompensation. 

Actions This Class IA drug shows actions similar to those of quinidine. Disopyramide [dye so PEER a mide] produces a negative inotropic effect that is greater than the weak effect exerted by quinidine and procainamide, and unlike the latter drugs, disopyramide causes peripheral vasoconstriction. The drug may produce a clinically important decrease in myocardial contractility in patients with preexisting impairment of left ventricular function. Disopyramide is used for treatment of ventricular arrhythmias as an alternative to procainamide or quinidine. 

ATOMOXETINE 1. ANTIARRHYTHMICS - amiodarone, disopyramide, procainamide, propafenone 2. ANTIBIOTICS — macrolides (especially azithromycin, clarithromycin, parenteral erythromycin, telithromycin), quinolones (especially moxifloxacin), quinupristin/dalfopristin 3. ANTICANCER AND IMMUNOMODU-LATING DRUGS - arsenic trioxide 4. ANTIDEPRESSANTS - TCAs, venlafax-ine 5. ANTIEMETICS - dolasetron 6. ANTIFUNGALS-fluconazole, posaconazole, voriconazole 7. ANTIHISTAMINES-terfenadine, hydroxyzine, mizolastine 8. ANTIMALARIALS -artemether with lumefantrine, chloro-quine, hydroxychloroquine, mefloquine, quinine 9. ANTIPROTOZOALS-pentamidine isetionate 10. ANTIPSY-CHOTICS - atypicals, phenothiazines, pimozide 11. BETA-BLOCKERS - sotalol 12. BRONCHODILATORS - parenteral bronchodilators Risk of ventricular arrhythmias, particularly torsades de pointes Additive effect these drugs cause prolongation of the Q-T interval Avoid co-administration... 

Interactions. Erythromycin and the other macro-lides are enzyme inhibitors and interfere with the metabolic inactivation of some drugs, e.g. warfarin, carbamazepine, theophylline, disopyramide, increasing their effects. Reduced inactivation of terfena-dine may lead to serious cardiac arrhythmias, and of ergot alkaloids may cause ergotism. 

P. Le Corre, D. Gibassier, C. Descaves, P. Sado, J. C. Daubert, and R, Le Verge, "Clinical pharmacokinetics of levorotatory and racemic disopyramide, at steady state, following oral administration in patients with ventricular arrhythmias," /. Clin. Pharmacol., 29 1089-1096 a989). 

Disopyramide has been used in treating both the supraventricular and ventricular arrhythmias occurring in patients with HCM. In addition, the negative inotropic effect and the ability to increase peripheral vascular resistance attributed to disopyramide have been used to reduce... 

Moricizine (600 to 900 mg/day given every 8 hours in three equally divided doses) is indicated in the treatment of documented ventricular arrhythmias, such as sustained ventricular tachycardia, that are life threatening. Because of the proarrhythmic effects of moricizine, its use should be reserved for patients in whom the benefits of treatment outweigh the risks. Moricizine is a class 1C antiarrhythmic agent with potent local anesthetic activity and myocardial-membrane-stabilizing effects. It shares some of the characteristics of the class lA (disopyramide, procainamide, or quinidine), of class IB (lidocaine, mexiletene, phenytoin, or tocainide), or class 1C agents (encainide, flecainide, or propafenone) in that it reduces the fast inward current carried by sodium ions. Moricizine shortens phase 2 and 3... 

Concomitant use of pimozide with quinidine, procainamide, disopyramide, and other antiarrhythmics, phenothi-azines (other antipsychotics), and antidepressants may further depress cardiac conduction and prolong the Q-T interval, resulting in serious arrhythmias. 

Concomitant use with thyroid medication, pimozole, and antiarrhythmic agents (quinidine, disopyramide, procainamide) may increase incidence of cardiac arrhythmias and conduction defects. 

Drugs with class lA action Quinidine is the class lA prototype. Other drugs with class lA actions include amiodarone, procainamide, and disopyramide. They affect both atrial and ventricular arrhythmias. These drugs block 1 and therefore slow conduction velocity in the atria, Purkinje fibers, and ventricular cells. The reduction in ventricular conduction results in increased QRS duration in the ECG. In addition, these drugs block Therefore, they increase action potential (AP) duration and the effective refractory period (ERP) in ad-... 

This interaction appears to be established, but its clinical importance is uncertain. The extent to which it would reduce the control of arrhythmias by disopyramide is unknown, but monitor the effects and the serum levels of disopyramide if phenobarbital is added or withdrawn. The manufacturer of disopyramide recommends avoiding using it in combination with inducers of the cytochrome P450 isoenzyme CYP3A, such as phenobarbital. Other barbiturates would be expected to interact similarly. 

A group of clinicians who had used single 400-mg oral doses of disopyramide successfully and with few adverse effects for reverting acute supraventricular arrhythmias, reported 5 cases of profound hypotension and collapse. Three of the patients developed severe epigastric pain. All 5 had previous myocardial disease and/or were taking myocardial depressants, either beta blockers or verapamil in small quantities [not specified]. ... 

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