Catecholamines chlorinated

Systemic Effects. The use of 1,1-dichloroethane as an anesthetic was discontinued when it was discovered that this compound induced cardiac arrhythmias in humans at anesthetic doses (approximately 105,000 mg/m, or 26,000 ppm). The mechanism of action for the induction of cardiac arrhythmias by 1,1-dichloroethane is not known. However, when the cardiac muscle is markedly depressed, it is more susceptible to the effects of catecholamines. Secretion of catecholamines is increased in this situation by compensatory and other mechanisms, resulting in excessive spontaneous contractions of the heart. This is an effect common to exposure to other chlorinated aliphatics at high concentrations (Reinhardt et al. 1971). Cardiovascular toxicity has not been reported in animals following exposure to 1,1-dichloroethane. 

Certain foreign compounds may cause an increase in sensitivity of a particular tissue to endogenous substances such as catecholamines. For instance exposure to some halogenated hydrocarbons, such as the fluorinated and chlorinated compounds used in aerosol spray cans and fire extinguishers, may cause heightened sensitivity to catecholamines. The heart tissue is sensitized by... 

Table IV. Ring-Chlorinated Derivatives of Adrenergic Catecholamines (31)...

A. Chlorinated hydrocarbons are neurotoxins that interfere with transmission of nerve impulses, especially in the brain, resulting in behavioral changes, involuntary muscle activity, and depression of the respiratory center. They may also sensitize the myocardium to arrhythmogenic effects of catecholamines, and many can cause liver or renal injury, possibly owing to generation of toxic metabolites. In addition, some chlorinated hydrocarbons may be carcinogenic. 

B. As with chlorinated hydrocarbons, freons may potentiate cardiac arrhythmias by increasing the sensitivity of the myocardium to the effects of catecholamines. 

C. Control of ventricular tachyantry mias caused by excessive myocardial catecholamine sensitivity (eg, chloral hydrate and chlorinated hydrocarbon solvents). 

A. To control excessive sinus tachycardia or ventricular arrhythmias caused by catecholamine excess (eg, theophylline or caffeine), sympathomimetic drug intoxication (eg, amphetamines, pseudoephedrine, or cocaine), or excessive myocardial sensitivity (eg, chloral hydrate, freons, or chlorinated and other hydrocarbons). 

Hydrocarbon solvents, especially chlorinated hydrocarbons, and chlorofluorocarbon propellants all enhance the sensitivity of the myocardium to catecholamine-induced dysrhythmias. 

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