DEXAMETHASONE, DEXAMETHASONE SODIUM PHOSPHATE, DEXAMETHASONE 21-ISONICOTINATE
Chemistry - A synthetic glucocorticoid, dexamethasone occurs as an odorless, white to practicallywhite, crystalline powder that melts with some decomposition at about 250°C. It is practicallyinsoluble in water and sparingly soluble in alcohol. Dexamethasone sodium phosphate occurs as anodorless or having a slight odor, white to slightly yellow, hygroscopic powder. One gram of issoluble in about 2 ml of water; it is slightly soluble in alcohol. Dexamethasone 21-isonicotinateoccurs as a nearly odorless and tasteless, white to slight yellow, crystalline powder. 1.3 mg of dexamethasone sodium phosphate is equivalent to 1 mg of dexamethasone; 4 mg/ml ofdexamethasone sodium phosphate injection is approximately equivalent to 3 mg/ml of dexamethasone.
Storage, Stability, CompatibilityDexamethasone is heat labile and should be stored at roomtemperature (15-30°C) unless otherwise directed by the manufacturer. Dexamethasone sodiumphosphate injection should be protected from light. Dexamethasone tablets should be stored inwell-closed containers.
Dexamethasone sodium phosphate for injection is reportedly compatible with the followingdrugs: amikacin sulfate, aminophylline, bleomycin sulfate, cimetidine HCl, glycopyrrolate, lidocaine
HCl, nafcillin sodium, netilmicin sulfate, prochlorperazine edisylate and verapamil.
It is reportedly incompatible with: daunorubicin HCl, doxorubicin HCl, metaraminol bitartrate, and vancomycin. Compatibility is dependent upon factors such as pH, concentration, temperatureand diluents used. It is suggested to consult specialized references for more specific information(e.g., Handbook on Injectable Drugs by Trissel; see bibliography).
Contraindications/Precautions - Because dexamethasone has negligible mineralocorticoid effect, it should generally not be used alone in the treatment of adrenal insufficiency. For more information refer to the Glucocorticoid monograph.