DIGOXIN DOSAGE IN INFANTS

Abstract

Digoxin is suggested as the drug of choice for digitalis therapy in infants and children, primarily because of its rapid dissipation. The use of average dosage figures, while necessary in starting therapy, is often unsatisfactory and may be hazardous unless one appreciates the great range of sensitivity to digitalis amongst patients. The principle set forth by Withering and repeated by many since then that each patient treated with digitalis is a titration experiment, still holds. Our studies and experience with digoxin in normal infants as well as in those with heart disease enable us to propose a digitalizing regimen which has proven effective and yet safe in most of the infants who can benefit from digitalis therapy. We recommend an initial "digitalizing dose" of 75 µg/kg in 24 hours, orally or intramuscularly. One-half or one-third is given first and the remainder in equal portions every 6 to 8 hours. If the desired clinical effect is evident, a maintenance dose of 25 µg/kg once daily is administered. If, however, the desired clinical effect has not been achieved after the initial "digitalizing dose," 25 µg/kg should be given under careful clinical and electrocardiographic observation every 6, 8 or 12 hours (depending upon the severity of the failure) until either a satisfactory effect or toxic signs appear. The maintenance dose may then be proportionately larger. Changes in S-T segment and T wave in the electrocardiogram are not considered signs of toxicity. The development of vomiting or the appearance in the electrocardiogram of significant conduction defects, or arrhythmias are indications of digitalis toxicity. Relatively large amounts of digoxin may be necessary in some infants both initially and for maintenance in order to obtain maximum benefit from the drug.