dexamethasone oral, Decadron, DexPak (cont.)

Pharmacy Author:
Medical and Pharmacy Editor:

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.

Prolonged use of dexamethasone can depress the ability of body's adrenal glands to produce corticosteroids. Abruptly stopping dexamethasone in these individuals can cause symptoms of corticosteroid insufficiency, with accompanying nausea, vomiting, and even shock. Therefore, withdrawal of dexamethasone usually is accomplished by gradually reducing the dose. Gradually tapering dexamethasone not only minimizes the symptoms of corticosteroid insufficiency, but also reduces the risk of an abrupt flare of the disease under treatment.

Dexamethasone and other corticosteroids can mask signs of infection and impair the body's natural immune response that is important in fighting infection. Patients on corticosteroids are more susceptible to infections and can develop more serious infections than individuals not receiving corticosteroids. For example, chickenpox and measles viruses can produce serious and even fatal illnesses in patients on high doses of dexamethasone. Live virus vaccines, such as smallpox vaccine, should be avoided in patients taking high doses of dexamethasone, since even vaccine viruses may cause disease in these patients. Some infectious organisms, such as tuberculosis (TB) and malaria, can remain dormant in a patient for years. Dexamethasone and other corticosteroids can reactivate dormant infections. Patients with dormant tuberculosis may require treatment of the TB while undergoing corticosteroid treatment.

By interfering with the patient's immune response, dexamethasone can impede the effectiveness of vaccinations. Dexamethasone can also interfere with the tuberculin (TB) skin test and cause falsely negative results in patients with dormant tuberculosis infection.

Dexamethasone impairs calcium absorption and new bone formation. Patients on prolonged treatment with dexamethasone and other corticosteroids can develop osteoporosis and an increased risk of bone fractures. Supplemental calcium and vitamin D are encouraged to slow this process of bone thinning. It has been demonstrated in some groups of patients treated with steroids that the loss of bone may be prevented by treatment with biphosphonate drugs, for example, alendronate (Fosamax).

In rare individuals, destruction of large joints can occur while undergoing treatment with dexamethasone or other corticosteroids. These patients experience severe pain in the involved joints, and can require joint replacements. The reason behind such destruction is not clear.

Reference: FDA Prescribing Information


Last Editorial Review: 3/12/2009



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