Pharmacy Author: Omudhome Ogbru, PharmD
Medical and Pharmacy Editor: Jay W. Marks, MD

GENERIC NAME: dexamethasone oral

BRAND NAME: Decadron, DexPak

DRUG CLASS AND MECHANISM: Dexamethasone is a synthetic (man-made) corticosteroid. Corticosteroids are naturally-occurring chemicals produced by the adrenal glands located above the kidneys. Corticosteroids affect the function of many cells within the body and suppress the immune system. Corticosteroids also block inflammation and are used in a wide variety of inflammatory diseases affecting many organs.

PRESCRIPTION: Yes

GENERIC AVAILABLE: Yes

PREPARATIONS: Tablets: 0.25, 0.5, 0.75, 1, 1.5, 2, 4, and 6 mg. Elixir: 0.5 mg /5 mL. Solution: 0.5, 1 mg/5 ml

STORAGE: Dexamethasone should be stored at 68-77 F (20-25 C) and not frozen.

PRESCRIBED FOR: Dexamethasone is used for reducing inflammation in many conditions. Some examples include rheumatoid arthritis, systemic lupus, acute gouty arthritis, psoriatic arthritis, ulcerative colitis, and Crohn's disease. Severe allergic conditions that fail to respond to other treatments also may respond to dexamethasone. Examples include bronchial asthma, allergic rhinitis, drug-induced dermatitis, and contact and atopic dermatitis. Chronic skin conditions treated with dexamethasone include dermatitis herpetiformis, pemphigus, severe psoriasis and severe seborrheic dermatitis. Chronic allergic and inflammatory conditions of the uvea, iris, conjunctiva and optic nerves of the eyes also are treated with dexamethasone.

Dexamethasone is used in the treatment of cancers of the white blood cells (leukemias), and lymph gland cancers (lymphomas). Blood diseases involving destruction by the body's own immune system of platelets (idiopathic thrombocytopenia purpura), and red blood cells (autoimmune hemolytic anemia) also are treated with dexamethasone. Other miscellaneous conditions treated with dexamethasone include thyroiditis and sarcoidosis. Finally, dexamethasone is used as replacement therapy in patients whose adrenal glands are unable to produce sufficient amounts of corticosteroids.

DOSING: Dosage requirements of corticosteroids vary greatly among individuals and the diseases being treated. In general, the lowest possible effective dose is used. The initial oral dose is 0.75 to 9 mg daily depending on the disease. The initial dose should be adjusted based on response. Corticosteroids given in multiple doses throughout the day are more effective but also are more toxic as compared with the same total daily dose given once daily, or every other day.

DRUG INTERACTIONS: Corticosteroids may increase or decrease the effect of blood thinners, for example, warfarin (Coumadin). Blood clotting should be monitored and the dose of blood thinner adjusted in order to achieve the desired level of blood thinning when patients receiving blood thinners are begun on corticosteroids, including dexamethasone.

Phenobarbital, ephedrine, phenytoin (Dilantin), and rifampin (Rifadin, Rimactane) may increase the breakdown of corticosteroids by the liver, resulting in lower blood levels and reduced effects. Therefore, the dose of corticosteroid may need to be increased if treatment with any of these agents is begun.

PREGNANCY: Dexamethasone has not been adequately evaluated in pregnant women.

NURSING MOTHERS: Dexamethasone has not been adequately evaluated in nursing mothers. Corticosteroids appear in breast milk and may cause side effects in infants.

SIDE EFFECTS: Side effects of dexamethasone depend on the dose, the duration and the frequency of administration. Short courses of dexamethasone usually are well tolerated with few and mild side effects. Long term, high dose dexamethasone usually will produce predictable and potentially serious side effects. Whenever possible, the lowest effective dose of dexamethasone should be used for the shortest possible length of time to minimize side effects. Alternate day dosing also can help reduce side effects.

Side effects of dexamethasone and other corticosteroids range from mild annoyances to serious irreversible damage. Side effects include fluid retention, weight gain, high blood pressure, loss of potassium, headache, muscle weakness, puffiness of and hair growth on the face, thinning and easy bruising of skin, glaucoma, cataracts, peptic ulceration, worsening of diabetes, irregular menses, growth retardation in children, convulsions, and psychic disturbances. Psychic disturbances include depression, euphoria, insomnia, mood swings, personality changes, and even psychotic behavior.