DEXAMETHASONE

DEXAMETHASONE (dex-a-meth'a-sone) Decadron, Dexamethasone Intensol, Maxidex, Mymethasone DEXAMETHASONE SODIUM PHOSPHATE Decadron Phosphate, Maxidex Ophthalmic Classifications: hormone; adrenal corticosteroid; glucocorticoid; Therapeutic:adrenal corticosteroid Prototype: Prednisone Pregnancy Category: C

Availability

Dexamethasone: 0.25 mg, 0.5 mg, 0.75 mg, 1 mg, 1.5 mg, 2 mg, 4 mg, 6 mg tablets; 0.5 mg/5 mL, 0.5 mg/0.5 mg oral solution; 0.01%, 0.04% topical aerosol; Dexamethasone sodium phosphate: 4 mg/mL, 10 mg/mL, 20 mg/mL, 24 mg/mL injection; 0.1% cream; 0.1% ophthalmic solution, suspension; 0.05% ophthalmic ointment

Action

Long-acting synthetic adrenocorticoid with intense antiinflammatory (glucocorticoid) activity and minimal mineralocorticoid activity. Antiinflammatory action: Prevents accumulation of inflammatory cells at sites of infection; inhibits phagocytosis, lysosomal enzyme release, and synthesis of potent mediators of inflammation, prostaglandins, and leukotrienes; reduces capillary dilation and permeability. Immunosuppression: Not clearly understood, but may be due to prevention or suppression of delayed hypersensitivity immune reaction.

Therapeutic Effect

Has antiinflammatory and immunosuppression properties.

Uses

Adrenal insufficiency concomitantly with a mineralocorticoid; inflammatory conditions, allergic states, collagen diseases, hematologic disorders, cerebral edema, and addisonian shock. Also palliative treatment of neoplastic disease, as adjunctive short-term therapy in acute rheumatic disorders and GI diseases, and as a diagnostic test for Cushing's syndrome and for differential diagnosis of adrenal hyperplasia and adrenal adenoma.

Unlabeled Uses

As an antiemetic in cancer chemotherapy; as a diagnostic test for endogenous depression; and to prevent hyaline membrane disease in premature infants.

Contraindications

Systemic fungal infection, acute infections, active or resting tuberculosis, vaccinia, varicella, administration of live virus vaccines (to patient, family members), latent or active amebiasis; Cushing's syndrome; neonates or infants <1300 g; pregnancy (category C), lactation. Topical use: Rosacea, perioral dermatitis; venous statis ulcers. Ophthalmic use: Primary open-angle glaucoma, eye infections, superficial ocular herpes simplex, keratitis, and tuberculosis of eye.

Cautious Use

Stromal herpes simplex, keratitis, GI ulceration, renal disease, diabetes mellitus, hypothyroidism, myasthenia gravis, CHF, cirrhosis, psychic disorders, seizures; children; coagulopathy.

Route & Dosage

Allergies, Inflammation, Neoplasias Adult: PO 0.25–4 mg b.i.d. to q.i.d. IM 8–16 mg q1–3wk or 0.8–1.6 mg intralesional q1–3wk IV 0.75–0.9 mg/kg/d divided q6–12h Child: PO/IV/IM 0.08–0.3 mg/kg/d divided q6–12h Cerebral Edema Adult: IV 10 mg followed by 4 mg q6h, reduce dose after 2–4 d then taper over 5–7 d Child: PO/IV/IM 1–2 mg/kg loading dose, then 1–1.5 mg/kg/d divided q4–6h x 5 d (max: 16 mg/d) Shock Adult: IV 1–6 mg/kg as a single dose or 40 mg repeated q2–6h if needed or 20 mg bolus then 3 mg/kg/d Dexamethasone Suppression Test Adult: PO 0.5 mg q6h for 48 h Inflammation Adult/Child: Ophthalmic/Topical/Inhalation/Intranasal See Appendix A.

Administration

Oral

• Give the once-daily dose in the a.m. with food or liquid of patient's choice.
• Taper dosage over a period of time before discontinuing because adrenal suppression can occur with prolonged use.
• Do not store or expose aerosol to temperature above 48.9° C (120° F); do not puncture or discard into a fire or an incinerator.

Intramuscular

• Give IM injection deep into a large muscle mass (e.g., gluteus maximus). Avoid SC injection: Atrophy and sterile abscesses may occur.
• Use repository form, dexamethasone acetate, for IM or local injection only. The white suspension settles on standing; mild shaking will resuspend drug.

Intravenous PREPARE: Direct: Give undiluted.  Intermittent: Dilute in D5W or NS for infusion.   ADMINISTER: Direct: Give direct IV push over 30 sec or less.  Intermittent: Set rate as prescribed or according to amount of solution to infuse.   INCOMPATIBILITIES Solution/additive: Daunorubicin, diphenhydramine, doxorubicin, doxapram, glycopyrrolate, metaraminol, phenobarbital, vancomycin. Y-site: Ciprofloxacin, fenoldopam, idarubicin, midazolam, topotecan.

• Store at 15°–30° C (59°–86° F) unless otherwise directed.

Adverse Effects (≥1%)

Aerosol Therapy: Nasal irritation, dryness, epistaxis, rebound congestion, bronchial asthma, anosmia, perforation of nasal septum. Systemic Absorption—CNS: Euphoria, insomnia, convulsions, increased ICP, vertigo, headache, psychic disturbances. CV: CHF, hypertension, edema. Endocrine: Menstrual irregularities, hyperglycemia; cushingoid state; growth suppression in children; hirsutism. Special Senses: Posterior subcapsular cataract, increased IOP, glaucoma, exophthalmos. GI: Peptic ulcer with possible perforation, abdominal distension, nausea, increased appetite, heartburn, dyspepsia, pancreatitis, bowel perforation, oral candidiasis. Musculoskeletal: Muscle weakness, loss of muscle mass, vertebral compression fracture, pathologic fracture of long bones, tendon rupture. Skin: Acne, impaired wound healing, petechiae, ecchymoses, diaphoresis, allergic dermatitis, hypo- or hyperpigmentation, SC and cutaneous atrophy, burning and tingling in perineal area (following IV injection).

Diagnostic Test Interference

Dexamethasone suppression test for endogenous depression: false-positive results may be caused by alcohol, glutethimide, meprobamate; false-negative results may be caused by high doses of benzodiazepines (e.g., chlordiazepoxide and cyproheptadine), long-term glucocorticoid treatment, indomethacin, ephedrine, estrogens or hepatic enzyme-inducing agents (phenytoin) may also cause false-positive results in test for Cushing's syndrome.

Interactions

Drug: barbiturates, phenytoin, rifampin increase steroid metabolism—dosage of dexamethasone may need to be increased; amphotericin B, diuretics compound potassium loss; ambenonium, neostigmine, pyridostigmine may cause severe muscle weakness in patients with myasthenia gravis; may inhibit antibody response to vaccines, toxoids.

Pharmacokinetics

Absorption: Readily from GI tract. Onset: Rapid. Peak: 1–2 h PO; 8 h IM. Duration: 2.75 d PO; 6 d IM; 1–3 wk intralesional, intraarticular. Distribution: Crosses placenta; distributed into breast milk. Elimination: Hypothalamus-pituitary axis suppression: 36–54 h. Half-Life: 3–4.5 h.

Nursing Implications

Assessment & Drug Effects

• Monitor and report S&S of Cushing's syndrome (see Appendix F) or other systemic adverse effects.
• Monitor neonates born to a mother who has been receiving a corticosteroid during pregnancy for symptoms of hypoadrenocorticism.
• Monitor for S&S of a hypersensitivity reaction (see Appendix F). The acetate and sodium phosphate formulations may contain bisulfites, parabens, or both; these inactive ingredients are allergenic to some individuals.

Patient & Family Education

• Take drug exactly as prescribed.
• Report lack of response to medication or malaise, orthostatic hypotension, muscular weakness and pain, nausea, vomiting, anorexia, hypoglycemic reactions (see Appendix F), or mental depression to physician. These symptoms may signal hypoadrenocorticism.
• Report changes in appearance and easy bruising to physician. These symptoms may signal hyperadrenocorticism.
• Note: Hiccups that occur for several hours following each dose may be a complication of high-dose oral dexamethasone.
• Keep appointments for checkups; make sure electrolytes and BP are evaluated during therapy at regular intervals.
• Add potassium-rich foods to diet; report signs of hypokalemia (see Appendix F). Concomitant potassium-depleting diuretic can enhance dexamethasone-induced potassium loss.
• Note: Dexamethasone dose regimen may need to be altered during stress (e.g., surgery, infections, emotional stress, illness, acute bronchial attacks, trauma). Consult physician if change in living or working environment is anticipated.
• Discontinue drug gradually under the guidance of the physician.
• Note: It is important to prevent exposure to infection, trauma, and sudden changes in environmental factors, as much as possible, because drug is an immunosuppressor.

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Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; Canadian drug name; Prototype drug