Dexamethasone

Adults: In general, glucocorticoid dosage depends on the severity of the condition and the response of the patient. If no favourable response is noted within a couple of days, continuing glucocorticoid therapy is not advisable. In chronic conditions requiring long term therapy, the lowest dosage that gives adequate, though not necessarily complete, relief should be used. For tablets, in adult patients daily oral dosages vary from 1 mg to 10 mg, and in children from 0.03 to 0.20 mg per kg body weight, according to the individual response. In some patients higher dosages may be needed temporarily to control the disease. As soon as circumstances permit, the dosage should be decreased. For a short dexamethasone suppression test, 1 mg of dexamethasone is given at 11 p.m. and plasma cortisol is measured the next morning. Patients who do not show a decrease in cortisol can be given a longer test, in which 0.5 mg of dexamethasone is given at 6 hour intervals for 48 hours, followed by 2 mg every 6 hours for a further 48 hours. Twenty four hour urine collections are made before, during and at the end of the test to determine 17 alpha hydroxycorticoids. For injection, dexamethasone can be given by intravenous, intramuscular or local injection. Dexamethasone injections can also be diluted with an infusion fluid or injected directly into the infusion line. Intravenous injections of large doses should be given slowly, over several minutes. Intramuscular administration should be given by deep intramuscular injection to prevent atrophy of the subcutaneous fatty tissue. Intra articular injections should be given under strictly aseptic conditions, since glucocorticoids reduce resistance to infection. When diluted with these infusion fluids, dexamethasone keeps its potency for at least 24 hours at room temperature and in daylight conditions. Sodium chloride 0.9%, anhydrous glucose 5%, invert sugar 10%, sorbitol 5%, Ringer's solution and Hartman's solution, also known as Ringer lactate, can be used as infusion fluids among others. The dosage of dexamethasone depends on the severity of the condition and the response of the patient. For systemic therapy in adults, daily doses of 0.05 to 0.20 mg per kg body weight are usually sufficient. For emergencies, such as anaphylaxis, acute severe asthma or cerebral edema, substantially higher doses are required. An initial dose of 10 to 20 mg IV is followed by 6 mg IV or IM every 6 hours, until a satisfactory result is obtained, after which the dosage has to be tapered off gradually. For local therapy, the following doses are recommended. Intra articularly, 2 to 4 mg in large joints and 0.8 to 1 mg in small joints. Intrabursally, 2 to 4 mg, and in tendon sheaths, 0.4 to 1 mg. The frequency of these injections may vary from every 3 to 5 days to every 2 to 3 weeks.