DOSING: The usual dosage for adults is 250 mg every 6 hours, 333 mg every 8 hours or 500 mg every 12 hours. Doses may be increased up to 4 g/day according to the severity of the infection.
In children, the usual dosage is 30 to 50 mg/kg/day with age, weight, and severity of the infection being taken into consideration to determine the appropriate dosage.
Erythromycin may be taken with or without food; however optimal blood levels of erythromycin are obtained when taken on an empty stomach (at least 30 minutes and preferably 2 hours before or after meals).
DRUG INTERACTIONS: Erythromycin when used with antiarrhythmic drugs such as, amiodarone (Cordarone), bretylium (Bretylol), disopyramide (Norpace), dofetilide (Tikosyn), procainamide (Pronestyl), quinidine (Quinaglute, Quinidex, Quinora) and sotalol (Betapace) exaggerates the effect of the antiarrhythmic drugs which may give rise to abnormal heart rhythms> such as torsades de pointes.
Theophyllines such as theophylline (Theo-Dur), oxtriphylline (Choledyl SA), and aminophylline (Phyllocontin) reduce erythromycin blood levels by increasing elimination of erythromycin by the kidneys, which may reduce the effectiveness of erythromycin. Conversely, erythromycin inhibits the metabolism (breakdown) of theophyllines by the liver and causes an increase in blood levels of theophylline. High theophylline levels may give rise to side effects such as seizures and disturbances in heart rhythm. Therefore, the dose of theophyllines should be reduced or theophylline levels in the blood should be measured in patients taking erythromycin.
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