Insect repellent (N,N-diethyl-m-toluamide) cardiovascular toxicity in an adult.

OBJECTIVE: To describe a case of N,N-diethyl-m-toluamide (DEET)-induced cardiovascular toxicity in an adult and reviews other cases that have been reported in the published literature. Human and animal data available on DEET pharmacokinetics are reviewed and factors that predispose an individual to DEET toxicity are identified. DATA SOURCES: Case report information was obtained through personal contact with the patient during hospitalization and by telephone, and also from the patient's medical records. Computerized literature searches were conducted with the following systems to obtain medical literature on DEET toxicity: TOXLINE, International Pharmaceutical Abstracts, and MEDLINE. Index Medicus was searched manually. STUDY SELECTION: All reported cases of DEET toxicity in children and adults were reviewed. DATA EXTRACTION: Case reports were evaluated for the quantity of the DEET exposure (topical or oral), the clinical manifestations of the exposure, and the outcome of the exposure. DATA SYNTHESIS: This case is similar in some aspects to those already in the literature; however, very few cases of DEET toxicity in adults have been reported. Cardiovascular toxicity in humans related to DEET application has not been previously reported in the published medical literature. DEET exposure (topical or oral) results in a highly variable clinical course. Whether the outcome is death or recovery without sequelae is difficult to predict. CONCLUSIONS: Adults, as well as children, are at risk for toxicity from insect repellents. The use of highly concentrated DEET-containing insect repellents should be avoided to reduce the risk of toxicity in both children and adults. The consequences of DEET toxicity are variable and unpredictable.

Pharmacodynamic distinctions between ouabain, digoxin and digitoxin.

Current pharmacologic texts recognize no significant pharmacodynamic differences between the various cardiac glycosides. To reconsider this concept, a special recording device was constructed so that electrocardiograms and phonocardiograms could be obtained in small mammals without anesthesia or premedication, and a spectrum of cardiac glycosides was studied. Utilizing guinea-pigs, cardiac rate reduction of 20% was sought and achieved with 0.07 mg/kg ouabain, 0.34 mg/kg digoxin and 1.12 mg/kg digitoxin. With comparable rate reduction, digitoxin produced significantly greater shortening of electro-mechanical systole than did ouabain or digoxin (P less than 0.05). Other authors have shown that cardiac glycosides produce slowing of cardiac rate prior to onset of positive inotropic effect. Therefore it is probable that for a given amount of vagal effect (sinoatrial slowing) digitoxin possesses greater positive inotropic effect (abbreviation of electromechanical systole) in guinea-pigs than do ouabain or digoxin. A review of the literature suggests that the same holds true for humans.