Hypotension disopyramide

Further class IA drugs include the open state blockers procainamide and disopyramide with electrophysiolog-ical effects similar to those of quinidine procainamide lacks the antimuscarinic and antiadrenergic effects. Characteristic side effects of procainamide are hypotension and immunological disorders. 

When two antiarrhythmic dragp are administered concurrently the patient may experience additive effects and is at increased risk for drug toxicity. When quinidine and procainamide are administered with digitalis, tiie risk of digitalis toxicity is increased. Hiarmacologic effects of procainamide may be increased when procainamide is administered with quinidine When quinidine is administered with the barbiturates or cimetidine, quinidine serum levels may be increased. When quinidine is administered with verapamil, there is an increased risk of hypotensive effects. When quinidine is administered with disopyramide, there is an increased risk of increased disopyramide blood levels and/or decreased serum quinidine levels. 

Dryness of the mouth and throat caused by die cholinergic blocking action of this drug also may occur. The nurse provides an adequate amount of fluid and instructs die patient to take frequent sips of water to relieve diis problem. In addition, postural hypotension may occur during die first few weeks of disopyramide therapy. The patient is advised to make position changes slowly. In some instances, the patient may require assistance in getting out of the bed or chair. 

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 major toxic reactions to disopyramide administration include hypotension, congestive heart failure, and conduction disturbances. These effects are the result of disopyramide s ability to depress myocardial contractility and myocardial conduction. Although disopyramide initially may produce ventricular tachyarrhythmias or ventricular fibrillation in some patients, the incidence of disopyramide-induced syncope in long-term therapy is not known. Most other toxic reactions (e.g., dry mouth, blurred vision, constipation) can be attributed to the anticholinergic properties of the drug. 

B. Anticholinergic agents, such as procainamide and disopyramide, are relatively contraindicated in patients with glaucoma. Procainamide is hypotensive rather than hypertensive. The local anesthetic activity of procainamide would have no adverse interaction with the diabetes mellitus. 

Hypersensitivity, sulphite allergy, excessive hypotension with disopyramide. Incompatible with dextrose and frusemide (furosemide). 

Negative inotropic effect Disopyramide can worsen cardiac failure and occasionally causes hypotension. 

The risk of myocardial depression with consequent hypotension is greatest when disopyramide is infused rapidly intravenously (SEDA-10, 149). Loading doses of disopyramide should therefore be infused slowly (over 30-60 minutes). 

Quinidine may be associated with a syndrome called cinchonism, which is characterized by headache, vertigo, and tinnitus. Procainamide may result in hypotension or a reversible syndrome similar to lupus erythematosus. Patients may develop positive antinuclear antibody (ANA) titers and complain of rash, arthralgia, and arthritis. Disopyramide is poorly tolerated due to its anticholinergic effects (urinary retention, dry mouth, blurred vision), and its use should be avoided in patients with congestive heart failure (CHF) due to negative inotropic effects. 

Disopyramide Anticholinergic effects (urinary retention, aggravation of glaucoma, constipation), hypotension, heart failure, tachyarrhythmias, torsade de pointes, heart block, nausea, vomiting, diarrhea, hypoglycemia, nervousness... 

Quinidine causes cinchonism (headache, vertigo, tinnitus) cardiac depression gastrointestinal upset and allergic reactions (eg, thrombocytopenic purpura). As noted in Chapter 13, quinidine reduces the clearance of digoxin and may increase the serum concentration of the glycoside to dangerous levels. Procainamide causes hypotension (especially when used parenterally) and a reversible syndrome similar to lupus erythematosus. Disopyramide has... 

V 1 1 IV. 6 hr half-life, partially metabolized in liver, low plasma protein binding. Hypersensitivity to amrinone. Amrinone increases diuresis in patients on diuretics. Digitalis inotropy and risk of toxicity increased (amrinone causes hypokalemia). Excessive hypotension with disopyramide. If cellular supplies of cAMP are depleted, amrinone will not be effective. Capable of increasing myocardial contraction even in the presence of p-adrenergic antagonists. 

D. Important drug interactions may result in toxicity. Hypotension is more likely to occur in patients taking beta blockers, nitrates, or both, especially if they are hypovolemic after diuretic therapy. Patients taking disopyramide or other... 

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