TERBUTALINE SULFATE

TERBUTALINE SULFATE
(ter-byoo'te-leen)
Classifications: bronchodilator; beta-adrenergic agonist;
Therapeutic: bronchodilator; respiratory smooth muscle relaxant; beta-adrenergic agonist
Prototype: Albuterol
Pregnancy Category: B

Availability

2.5 mg, 5 mg tablets; 0.2 mg aerosol; 1 mg/mL injection

Action

Synthetic adrenergic stimulant with selective beta₂- and negligible beta₁-agonist (cardiac) activity. Exerts preferential effect on beta₂ receptors in bronchial smooth muscles, inhibits histamine release from mast cells, and increases ciliary motility.

Therapeutic Effect

Relieves bronchospasm in chronic obstructive pulmonary disease (COPD) and significantly increases vital capacity. Promotes relaxation of vascular smooth muscle, contraction of GI and urinary sphincters, increase in renin, pancreatic beta-cell secretion, and serum HDL-cholesterol concentration. Increases uterine relaxation (thereby preventing or abolishing high intrauterine pressure).

Uses

Orally or subcutaneously as a bronchodilator in bronchial asthma and for reversible airway obstruction associated with bronchitis and emphysema.

Unlabeled Uses

To delay delivery in preterm labor.

Contraindications

Known hypersensitivity to sympathomimetic amines; severe hypertension and coronary artery disease; tachycardia with digitalis intoxication; within 14 d of MAO inhibitor therapy; angle-closure glaucoma.

Cautious Use

Angina, stroke, hypertension; diabetes mellitus; thyrotoxicosis; history of seizure disorders; MAOI therapy; cardiac arrhythmias; QT prolongation; thyroid disease; older adults; kidney and liver dysfunction; pregnancy (category B). Use further caution in second and third trimester (may inhibit uterine contractions and labor).

Route & Dosage

Bronchodilator
Adult: PO 2.5–5 mg t.i.d. at 6 h intervals (max: 15 mg/d) SC 0.25 mg q15–30min up to 0.5 mg in 4 h Inhaled 2 inhalations separated by 60 sec q4–6h
Adolescent: PO 12–15 y, 2.5 mg t.i.d. at 6 h intervals (max: 7.5 mg/d) SC 0.25 mg q15–30min up to 0.5 mg in 4 h Inhaled 2 inhalations separated by 60 sec q4–6h
Child: PO <12 y, 0.05 mg/kg q8h, gradually increase up to 0.15 mg/kg q8h (max: 5 mg/d) SC 0.005–0.01 mg/kg (max: 0.4 mg) q15–20min x 2 doses

Premature Labor
Adult: PO 2.5 mg q4–6h

Administration

Oral

Give with fluid of patient's choice; tablets may be crushed.
Be certain about recommended doses: PO preparation, 2.5 mg; SC, 0.25 mg. A decimal point error can be fatal.
Give with food if GI symptoms occur.

Subcutaneous

Give SC injection into lateral deltoid area.
Store all forms at 15°–30° C (59°–86° F); protect from light. Do not freeze.

Adverse Effects (≥1%)

CNS: Nervousness, tremor, headache, light-headedness, drowsiness, fatigue, seizures. CV: Tachycardia, hypotension or hypertension, palpitation, maternal and fetal tachycardia. GI: Nausea, vomiting. Body as a Whole: Sweating, muscle cramps.

Diagnostic Test Interference

Terbutaline may increase blood glucose and free fatty acids.

Interactions

Drug: Epinephrine, other sympathomimetic bronchodilators may add to effects; mao inhibitors, tricyclic antidepressants potentiate action on vascular system; effects of both beta-adrenergic blockers and terbutaline antagonized.

Pharmacokinetics

Absorption: 33–50% from GI tract. Onset: 30 min PO; <15 min SC; 5–30 min inhaled. Peak: 2–3 h PO; 30–60 min SC; 1–2 h inhaled. Duration: 4–8 h PO; 1.5–4 h SC; 3–4 h inhaled. Distribution: Into breast milk. Metabolism: In liver. Elimination: Primarily in urine, 3% in feces. Half-Life: 3–4 h.

Nursing Implications

Assessment & Drug Effects

Assess vital signs: Baseline pulse and BP and before each dose. If significantly altered from baseline level, consult physician. Cardiovascular adverse effects are more apt to occur when drug is given by SC route or it is used by a patient with cardiac arrhythmia.
Most adverse effects are transient, however, rapid heart rate may persist for a relatively long time.
Be aware that onset and degree of effect and incidence and severity of adverse effects of SC formulation resemble those of epinephrine.
Aerosolized drug produces minimal cardiac stimulation or tremors.
Be aware that muscle tremor is a fairly common adverse effect that appears to subside with continued use.
Monitor for symptoms of hypoglycemia in neonates born of a mother who used terbutaline during pregnancy.
Monitor patient being treated for premature labor for CV S&S for 12 h after drug is discontinued. Report tachycardia promptly.
Monitor I&O ratio. Fluid restriction may be necessary. Consult physician.

Patient & Family Education

Adhere to established dosage regimen (i.e., do not change dose intervals or omit, increase, or decrease the dose).
Inhalator therapy: Review instructions for use of inhalator (included in the package).
Learn how to take your own pulse and the limits of change that indicate need to notify the physician.
Consult physician if breathing difficulty is not relieved or if it becomes worse within 30 min after an oral dose.
Keep appointments with physician for evaluation of continued drug effectiveness and clinical condition. Terbutaline appears to have a short clinical period for sustained effectiveness.
Consult physician if symptomatic relief wanes; tolerance can develop with chronic use. Usually, a substitute agent will be prescribed.
Do not self-dose this drug, particularly during long-term therapy. In the face of waning response, increasing the dose will not improve the clinical condition and may cause overdosage. Understand that decreasing relief with continued treatment indicates need for another bronchodilator, not an increase in dose.
Do not puncture container, use or store it near heat or open flame, or expose to temperatures above 49° C (120° F), which may cause bursting. Contents of the aerosol (inhalator) are under pressure.
Do not use any other aerosol bronchodilator while being treated with aerosol terbutaline. Do not self-medicate with an OTC aerosol.
Do not use OTC drugs without physician approval. Many cold and allergy remedies, for example, contain a sympathomimetic agent that when combined with terbutaline may cause harmful adverse effects.

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

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