Hypokalemia arrhythmia with

Hypokalemia. Hypokalemia associated with thia2ide diuretic therapy has been knpHcated in the increased incidence of cardiac arrhythmias and sudden death (82). Several large clinical trials have been conducted in which the effects of antihypertensive dmg therapy on the incidence of cardiovascular complications were studied. The antihypertensive regimen included diuretic therapy as the first dmg in a stepped care (SC) approach to lowering the blood pressure of hypertensive patients. 

In theophyUine acute overdose patients are more likely to exhibit hypotension, hypokalemia, and/or metaboUc acidosis than are patients receiving chronic overmedication. Patients suffering chronic overmedication can develop seizures and serious arrhythmias with serum concentrations of 28-70 /xg/mL. Cardiac arrhythmias include atrial fibriUation or atrial flutter, multifocal atrial tachycardia, sinus tachycardia, supraventricular tachycardia and premature ventricular contractions with hemodynamic instabUity. 

No significant interactions have been reported when tiie expectorants are used as directed. The exception is iodine products. Lithium and other antithyroid drug may potentiate the hypotliyroid effects of these drug if used concurrently with iodine products. When potassium-containing medications and potassium-sparing diuretics are administered with iodine products, the patient may experience hypokalemia, cardiac arrhythmias, or cardiac arrest. Thyroid function tests may also be altered by iodine... 

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... 

Adverse reactions observed with the administration of terbutaline include nervousness, restlessness, tremor, headache, anxiety, hypertension, hypokalemia (low serum potassium), arrhythmias, and palpitations. A serious, but rare, adverse reaction is pulmonary edema... 

Hypokalemia and hypomagnesemia may cause muscle fatigue or cramps. Serious cardiac arrhythmias may occur, especially in patients receiving digitalis therapy, patients with LV hypertrophy, and those with ischemic heart disease. Low-dose therapy (e.g., 25 mg hydrochlorothiazide or 12.5 mg chlorthalidone daily) rarely causes significant electrolyte disturbances. 

Hypokalemia Hypokalemia prevention requires particular attention to the following Patients receiving digitalis and diuretics for CHF, hepatic cirrhosis, and ascites in aldosterone excess with normal renal function potassium-losing nephropathy certain diarrheal states or where hypokalemia is an added risk to the patient (eg, history of ventricular arrhythmias). 

Adjunctive treatment with thiazide or loop diuretics in CHF or hypertension to Help restore normal serum potassium in patients who develop hypokalemia on the kaliuretic diuretic prevent hypokalemia in patients who would be at particular risk if hypokalemia were to develop (eg, digitalized patients or patients with significant cardiac arrhythmias). 

Fluid overload occurs commonly in patients with renal failure, often in the absence of associated heart disease. If salt and water intake is not controlled in the patient who is oliguric or anaemic, plasma volume and symptoms of congestive heart failure ensue. Hypertension and coronary heart disease with increasing age contributes to the congestive heart failure. Diuretics like loop-diuretics or metolazone may be of value. Digitalis should be used with caution in patients on dialysis as cardiac arrhythmias may ensue in patients receiving dialysis in the presence of hypokalemia. 

Most patients with BN can be effectively treated as outpatients. Medical hospitalizations result from consequences of purging activities, such as frequent vomiting and abuse of laxatives and diuretics, which can create electrolyte imbalances and dehydration. These patients are at risk for developing cardiac arrhythmias due to hypokalemia. If the patient s serum potassium falls below 2.5 mEq/T, the patient should be hospitalized. Other medical emergencies are gastric dilatation and esophageal tears (both are rare). Cardiac failure caused by cardiomyopathy from ipecac intoxication is a medical emergency. 

Potassium Increases K+ permeability, K+ currents Slows ectopic pacemakers slows conduction velocity in heart Digitalis-induced arrhythmias arrhythmias associated with hypokalemia Oral, IV Toxicity Reentrant arrhythmias, fibrillation or arrest in overdose... 

Another serious toxicity of diuretic use, particularly in the cardiac patient, is hypokalemia. Hypokalemia can exacerbate underlying cardiac arrhythmias and contribute to digitalis toxicity. This can usually be avoided by having the patient reduce Na+ intake, thus decreasing Na+ delivery to the K+ -secreting collecting tubule. Patients who are noncompliant with a low Na+ diet must take oral KCI supplements or a K+-sparing diuretic. 

Rare adverse effects of fibrates include rashes, gastrointestinal symptoms, myopathy, arrhythmias, hypokalemia, and high blood levels of aminotransferases or alkaline phosphatase. A few patients show decreases in white blood count or hematocrit. Both agents potentiate the action of coumarin and indanedione anticoagulants, and doses of these agents should be adjusted. Rhabdomyolysis has occurred rarely. Risk of myopathy increases when fibrates are given with reductase inhibitors. The use of fenofibrate with rosuvastatin appears to minimize this risk. Fibrates should be avoided in patients with hepatic or renal dysfunction. There appears to be a modest increase in the risk of cholesterol gallstones. 

Alterations in the serum potassium level are hazardous because they can result in cardiac arrhythmias. Drugs that may cause hyperkalemia despite normal renal function include potassium itself, 13 blockers, digitalis glycosides, potassiumsparing diuretics, and fluoride. Drugs associated with hypokalemia include barium, 13 agonists, caffeine, theophylline, and thiazide and loop diuretics. 

Vomiting is common in patients with digitalis overdose. Hyperkalemia may be caused by acute digitalis overdose or severe poisoning, whereas hypokalemia may be present in patients as a result of long-term diuretic treatment. (Digitalis does not cause hypokalemia.) A variety of cardiac rhythm disturbances may occur, including sinus bradycardia, AV block, atrial tachycardia with block, accelerated junctional rhythm, premature ventricular beats, bidirectional ventricular tachycardia, and other ventricular arrhythmias. 

The cardiac arrhythmias are life-threatening, so the patient must be closely monitored, with facilities available for possible resuscitation. Drugs such as quinidine and procainamide are contraindicated, but lidocaine, propranolol, or phenytoin has been used safely and effectively. The arterial blood gas levels, pH, and electrolyte concentrations should be monitored so that metabolic acidosis or hypokalemia can be identified that would further aggravate the arrhythmias. Electrical pacing may be required if the antiarrhythmic drugs fail. Hyperpyrexia is treated by cooling. Seizures may be managed by intravenous doses of diazepam. 

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