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Monday, February 7, 2011

dexamethasone

Posted by Sampil 5:19 PM, under | No comments

dexamethasone
(dex a meth' a sone)

dexamethasone
Oral, topical dermatologic aerosol and gel, ophthalmic suspension:
Aeroseb-DexDecadronDexasone (CAN), HexadrolMaxidex Ophthalmic

dexamethasone acetate
IM, intra-articular, or soft-tissue injection:
Cortastat LA, Dalalone L.A., Decaject LA, Dexasone-L.A., Dexone LA, Solurex LA

dexamethasone sodium phosphate
IV, IM, intra-articularintralesional injection; respiratory inhalant; intranasal steroid; ophthalmic solution and ointment; topical dermatologic cream:
CortastatDalaloneDecadron Phosphate, DecajectDexasoneHexadrol Phosphate, Solurex

Pregnancy Category C

Drug classes
Corticosteroid
Glucocorticoid
Hormone

Therapeutic actions
Enters target cells and binds to specific receptors, initiating many complex reactions that are responsible for its anti-inflammatory and immunosuppressive effects.

Indications
·        Hypercalcemia associated with cancer
·        Short-term management of various inflammatory and allergic disorders, such as rheumatoid arthritis, collagen diseases (SLE), dermatologic diseases (pemphigus), status asthmaticus, and autoimmune disorders
·        Hematologic disorders: Thrombocytopenic purpuraerythroblastopenia
·        Trichinosis with neurologic or myocardial involvement
·        Ulcerative colitis, acute exacerbations of multiple sclerosis, and palliation in some leukemias and lymphomas
·        Cerebral edema associated with brain tumor, craniotomy, or head injury
·        Testing adrenocortical hyperfunction
·        Unlabeled uses: Antiemetic for cisplatin-induced vomiting, diagnosis of depression
·        Intra-articular or soft-tissue administration: Arthritis, psoriatic plaques
·        Respiratory inhalant: Control of bronchial asthma requiring corticosteroids in conjunction with other therapy
·        Intranasal: Relief of symptoms of seasonal or perennial rhinitis that responds poorly to other treatments
·        Dermatologic preparations: Relief of inflammatory and pruritic manifestations of dermatoses that are steroid-responsive
·        Ophthalmic preparations: Inflammation of the lid, conjunctiva, cornea, and globe

Contraindications and cautions
·        Contraindicated with infections, especially tuberculosis, fungal infections, amebiasisvaccinia and varicella, and antibiotic-resistant infections, allergy to any component of the preparation used.
·        Use cautiously with renal or hepatic disease; hypothyroidism, ulcerative colitis with impending perforation; diverticulitis; active or latent peptic ulcer; inflammatory bowel disease; CHF, hypertension, thromboembolic disorders; osteoporosis; seizure disorders; diabetes mellitus; lactation.

Available forms
Tablets—0.25, 0.5, 0.75, 1, 1.5, 2, 4, 6 mg; elixir—0.5 mg/5 mL; oral solution—0.5 mg/0.5 mL; injection—8 mg/mL, 16 mg/mL, 4 mg/mL, 10 mg/mL, 20 mg/mL, 24 mg/mL; aerosol—84 mcg/actuation; ophthalmic solution—0.1%; ophthalmic suspension—0.1%; ophthalmic ointment—0.05%; topical ointment—0.05%; topical cream—0.05%, 0.1%; topical aerosol—0.01%, 0.04%

Dosages
ADULTS
Systemic administration
Individualize dosage based on severity of condition and response. Give daily dose before 9 AM to minimize adrenal suppression. If long-term therapy is needed, alternate-day therapy with a short-acting steroid should be considered. After long-term therapy, withdraw drug slowly to avoid adrenal insufficiency. For maintenance therapy, reduce initial dose in small increments at intervals until the lowest clinically satisfactory dose is reached.
Oral (dexamethasone)
0.75–9 mg/day.
·        Suppression tests for Cushing's syndrome: 1 mg at 11 AM; assay plasma cortisol at 8 AM the next day. For greater accuracy, give 0.5 mg q 6 hr for 48 hr, and collect 24-hr urine to determine 17-OH-corticosteroid (17-OHCS) excretion.
·        Suppression test to distinguish Cushing's syndrome due to ACTH excess from that resulting from other causes: 2 mg q 6 hr for 48 hr. Collect 24-hr urine to determine 17-OHCS excretion.
IM (dexamethasone acetate)
8–16 mg; may repeat in 1–3 wk.
IV or IM (dexamethasone sodium phosphate)
0.5–9 mg/day.
·        Cerebral edema: 10 mg IV and then 4 mg IM q 6 hr until cerebral edema symptoms subside; change to oral therapy, 1–3 mg tid, as soon as possible and taper over 5–7 days.
PEDIATRIC PATIENTS
Individualize dosage based on severity of condition and response, rather than by strict adherence to formulas that correct adult doses for age or body weight. Carefully observe growth and development in infants and children on long-term therapy.
IV
·        Unresponsive shock: 1–6 mg/kg as a single IV injection (as much as 40 mg initially followed by repeated injections q 2–6 hr has been reported).
Intralesional (dexamethasone acetate)
ADULTS AND PEDIATRIC PATIENTS
4–16 mg intra-articular, soft tissue; 0.8–1.6 mg intralesional.
(dexamethasone sodium phosphate)
0.4–6 mg (depending on joint or soft-tissue injection site).
Respiratory inhalant (dexamethasone sodium phosphate)
84 mcg released with each actuation.
ADULTS
3 inhalations tidqid, not to exceed 12 inhalations/day.
PEDIATRIC PATIENTS
2 inhalations tidqid, not to exceed 8 inhalations/day.
Intranasal (dexamethasone sodium phosphate)
Each spray delivers 84 mcg dexamethasone.
ADULTS
2 sprays (168 mcg) into each nostril bid–tid, not to exceed 12 sprays (1,008 mcg)/day.
PEDIATRIC PATIENTS
1 or 2 sprays (84–168 mcg) into each nostril bid, depending on age, not to exceed 8 sprays (672 mcg). Arrange to reduce dose and discontinue therapy as soon as possible.
Topical dermatologic preparations
ADULTS AND PEDIATRIC PATIENTS
Apply sparingly to affected area bid–qid.
Ophthalmic solutions, suspensions
ADULTS AND PEDIATRIC PATIENTS
Instill 1 or 2 drops into the conjunctival sac q 1 hr during the day and q 2 hr during the night; after a favorable response, reduce dose to 1 drop q 4 hr and then 1 drop tidqid.
Ophthalmic ointment
ADULTS AND PEDIATRIC PATIENTS
Apply a thin coating in the lower conjunctival sac tidqid; reduce dosage to bid and then qid after improvement.

Pharmacokinetics
Route
Onset
Peak
Duration
Oral
Slow
1–2 hr
2–3 days
IM
Rapid
30–60 min
2–3 days
IV
Rapid
30–60 min
2–3 days

Metabolism: Hepatic; T1/2: 110–210 min
Distribution: Crosses placenta; enters breast milk
Excretion: Urine

IV facts
Preparation: No preparation required.
Infusion: Administer by slow, direct IV injection over 1 min.
Incompatibilities: Do not combine with daunorubicin, doxorubicin, metaraminolvancomycin.

Adverse effects
Adverse effects depend on dose, route, and duration of therapy.
Systemic administration
·        CNS: Seizures, vertigo, headaches, pseudotumor cerebrieuphoria, insomnia, mood swings, depression, psychosis, intracerebral hemorrhage, reversible cerebral atrophy in infants, cataracts, increased IOP, glaucoma
·        CV: Hypertension, CHF, necrotizing angiitis
·        Endocrine: Growth retardation, decreased carbohydrate tolerance, diabetes mellitus, cushingoid state, secondary adrenocortical and pituitary unresponsiveness
·        GI: Peptic or esophageal ulcer, pancreatitis, abdominal distention
·        GU: Amenorrhea, irregular menses
·        HematologicFluid and electrolyte disturbances, negative nitrogen balance, increased blood sugar, glycosuria, increased serum cholesterol, decreased serum T3 and T4 levels
·        Hypersensitivity: Anaphylactoid or hypersensitivity reactions
·        Musculoskeletal: Muscle weakness, steroid myopathy, loss of muscle mass, osteoporosis, spontaneous fractures
·        Other: Impaired wound healing; petechiaeecchymoses; increased sweating; thin and fragile skin; acne; immunosuppression and masking of signs of infection; activation of latent infections, including TB, fungal, and viral eye infections; pneumonia; abscess; septic infection; GI and GU infections
Intra-articular
·        Musculoskeletal: Osteonecrosis, tendon rupture, infection
Intralesional therapy
·        CNS: Blindness (when used on face and head—rare)
Respiratory inhalant
·        Endocrine: Suppression of HPA function due to systemic absorption
·        Respiratory: Oral, laryngeal, pharyngeal irritation
·        Other: Fungal infections
Intranasal
·        CNS: Headache
·        Dermatologic: Urticaria
·        Endocrine: Suppression of HPA function due to systemic absorption
·        GI: Nausea
·        Respiratory: Nasal irritation, fungal infections, epistaxis, rebound congestion, perforation of the nasal septum, anosmia
Topical dermatologic ointments, creams, sprays
·        Endocrine: Suppression of HPA function due to systemic absorption, growth retardation in children (children may be at special risk for systemic absorption because of their large skin surface area to body weight ratio)
·        Local: Local burning, irritation, acneiform lesions, striae, skin atrophy
Ophthalmic preparations
·        Endocrine: Suppression of HPA function due to systemic absorption; more common with long-term use
·        Local: Infections, especially fungal; glaucoma, cataracts with long-term use

Interactions
·        Decreased effects of anticholinesterases with corticotropin; profound muscular depression is possible
·        Decreased steroid blood levels with phenytoinphenobarbitalrifampin
·        Decreased serum levels of salicylates with dexamethasone
·        False-negative nitroblue-tetrazolium test for bacterial infection
·        Suppression of skin test reactions

Nursing considerations
Assessment
·        History for systemic administration: Active infections; renal or hepatic disease; hypothyroidism, ulcerative colitis; diverticulitis; active or latent peptic ulcer; inflammatory bowel disease; CHF, hypertension, thromboembolic disorders; osteoporosis; seizure disorders; diabetes mellitus; lactation
·        History for ophthalmic preparations: Acute superficial herpes simplex keratitis, fungal infections of ocular structures; vacciniavaricella, and other viral diseases of the cornea and conjunctiva; ocular TB
·        Physical for systemic administration: Baseline body weight, T; reflexes, and grip strength, affect, and orientation; P, BP, peripheral perfusion, prominence of superficial veins; R and adventitious sounds; serum electrolytes, blood glucose
·        Physical for topical dermatologic preparations: Affected area for infections, skin injury

Interventions
·        For systemic administration, do not give drug to nursing mothers; drug is secreted in breast milk.
·        WARNING: Give daily doses before 9 AM to mimic normal peak corticosteroid blood levels.
·        Increase dosage when patient is subject to stress.
·        Taper doses when discontinuing high-dose or long-term therapy.
·        Do not give live virus vaccines with immunosuppressive doses of corticosteroids.
·        For respiratory inhalant, intranasal preparation, do not use respiratory inhalant during an acute asthmatic attack or to manage status asthmaticus.
·        Do not use intranasal product with untreated local nasal infections, epistaxis, nasal trauma, septal ulcers, or recent nasal surgery.
·        WARNING: Taper systemic steroids carefully during transfer to inhalational steroids; adrenal insufficiency deaths have occurred.
·        For topical dermatologic preparations, use caution when occlusive dressings, tight diapers cover affected area; these can increase systemic absorption.
·        Avoid prolonged use near the eyes, in genital and rectal areas, and in skin creases.

Teaching points
Systemic administration
·        Do not stop taking the oral drug without consulting your health care provider.
·        Avoid exposure to infection.
·        Report unusual weight gain, swelling of the extremities, muscle weakness, black or tarry stools, fever, prolonged sore throat, colds or other infections, worsening of this disorder.
Intra-articular administration
·        Do not overuse joint after therapy, even if pain is gone.
Respiratory inhalant, intranasal preparation
·        Do not use more often than prescribed.
·        Do not stop using this drug without consulting health care provider.
·        Use the inhalational bronchodilator drug before using the oral inhalant product when using both.
·        Administer decongestant nose drops first if nasal passages are blocked.
Topical
·        Apply the drug sparingly.
·        Avoid contact with eyes.
·        Report any irritation or infection at the site of application.
Ophthalmic
·        Administer as follows: Lie down or tilt head backward and look at ceiling. Warm tube of ointment in hand for several minutes. Apply one-fourth to one-half inch of ointment, or drop suspension inside lower eyelid while looking up. After applying ointment, close eyelids and roll eyeball in all directions. After instilling eye drops, release lower lid, but do not blink for at least 30 seconds; apply gentle pressure to the inside corner of the eye for 1 minute. Do not close eyes tightly, and try not to blink more often than usual; do not touch ointment tube or dropper to eye, fingers, or any surface.
·        Wait at least 10 minutes before using any other eye preparations.
·        Eyes will become more sensitive to light (use sunglasses).
·        Report worsening of the condition, pain, itching, swelling of the eye, failure of the condition to improve after 1 week.

Adverse effects in Italic are most common; those in Bold are life-threatening.

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