terbutaline

REMS

Management of reversible airway disease due to asthma (SUBQ used for short-term control and oral agent as long-term control).

Unlabeled Use:

Management of preterm labor (tocolytic) (terbutaline injection may only be used for the short-term [≤72 hr]) management of preterm labor to prolong pregnancy and allow for the administration of antenatal steroids).

Action ⬆ ⬇

Results in the accumulation of cyclic adenosine monophosphate (cAMP) at beta-adrenergic receptors.
Produces bronchodilation.
Inhibits the release of mediators of immediate hypersensitivity reactions from mast cells.
Relatively selective for beta₂(pulmonary)-adrenergic receptor sites, with less effect on beta₁(cardiac)-adrenergic receptors.

Therapeutic effects:

Bronchodilation.

Pharmacokinetics ⬆ ⬇

Absorption: 35–50% absorbed following oral administration but rapidly undergoes first-pass metabolism. Well absorbed following SUBQ administration.

Distribution: Unknown.

Metabolism/Excretion: Partially metabolized by the liver; 60% excreted unchanged by the kidneys.

Half-Life: 5.7 hr.

Time/Action Profile ⬆ ⬇

(bronchodilation)

ROUTE	ONSET	PEAK	DURATION
PO	within 60–120 min	within 2–3 hr	4–8 hr
SUBQ	within 15 min	within 0.5–1 hr	1.5–4 hr

Contraind./Precautions ⬆ ⬇

Contraindicated in:

Hypersensitivity to adrenergic amines.

Use Cautiously in:

Cardiac disease;
Hypertension;
Hyperthyroidism;
Diabetes;
Glaucoma;
OB: Use for bronchodilation in pregnancy only if potential maternal benefit justifies potential fetal risk;
Geri: Older adults are more susceptible to adverse reactions (may require dose ).

Adv. Reactions/Side Effects ⬆ ⬇

CV: angina, arrhythmias, hypertension, myocardial ischemia, tachycardia

Endo: hyperglycemia

F and E: hypokalemia

GI: nausea, vomiting

Neuro: nervousness, restlessness, tremor, headache, insomnia

Resp: pulmonary edema

Interactions ⬆ ⬇

Drug-drug:

Concurrent use with other adrenergics (sympathomimetic) will have additive adrenergic side effects.
Use with MAO inhibitors may lead to hypertensive crisis.
Beta blockers may negate its therapeutic effect.

Drug-Natural Products:

Use with caffeine-containing herbs (cola nut, guarana, mate, tea, coffee) ↑ stimulant effect.

Route/Dosage ⬆ ⬇

Asthma

PO (Adults and Children >15 yr): 2.5–5 mg 3 times daily, given every 6 hr (not to exceed 15 mg/24 hr).
PO (Children 12–15 yr): 2.5 mg 3 times daily (given every 6 hr) (not to exceed 7.5 mg/24 hr).
PO (Children <12 yr): 0.05 mg/kg 3 times daily; may ↑ gradually (not to exceed 0.15 mg/kg 3–4 times daily or 5 mg/24 hr).
SC (Adults and Children ≥12 yr): 250 mcg; may repeat in 15–30 min (not to exceed 500 mcg/4 hr).
SC (Children <12 yr): 0.005–0.01 mg/kg; may repeat in 15–20 min.

Tocolysis (off-label)

IV (Adults ): 2.5–10 mcg/min infusion; ↑ by 5 mcg/min every 10 min until contractions stop (not to exceed 30 mcg/min). After contractions have stopped for 30 min, ↓ infusion rate to lowest effective amount and maintain for 4–8 hr.

Availability ⬆ ⬇

(Generic available)

Tablets: 2.5 mg; 5 mg
Solution for injection: 1 mg/mL

Assessment ⬆ ⬇

Bronchodilator: Assess lung sounds, respiratory pattern, pulse, and BP before administration and during peak of medication. Note amount, color, and character of sputum produced, and notify health care professional of abnormal findings.
Monitor pulmonary function tests before initiating therapy and periodically throughout therapy to determine effectiveness of medication.
Preterm Labor: Monitor maternal pulse and BP, frequency and duration of contractions, and fetal heart rate. Notify health care professional if contractions persist or increase in frequency or duration or if symptoms of maternal or fetal distress occur. Maternal side effects include tachycardia, palpitations, tremor, anxiety, and headache.
- Assess maternal respiratory status for symptoms of pulmonary edema (increased rate, dyspnea, rales/crackles, frothy sputum).
- Monitor mother and neonate for symptoms of hypoglycemia (anxiety; chills; cold sweats; confusion; cool, pale skin; difficulty in concentration; drowsiness; excessive hunger; headache; irritability; nausea; nervousness; rapid pulse; shakiness; unusual tiredness; or weakness) and mother for hypokalemia (weakness, fatigue, U wave on ECG, arrhythmias).

Lab Test Considerations:

May cause transient ↓ in serum potassium concentrations with higher than recommended doses.
- Monitor maternal serum glucose and electrolytes. May cause hypokalemia and hypoglycemia. Monitor neonate’s serum glucose, because hypoglycemia may also occur in neonates.

Toxicity and Overdose:

Symptoms of overdose include persistent agitation, chest pain or discomfort, decreased BP, dizziness, hyperglycemia, hypokalemia, seizures, tachyarrhythmias, persistent trembling, and vomiting.
- Treatment includes discontinuing beta-adrenergic agonists and symptomatic, supportive therapy. Cardioselective beta blockers are used cautiously because they may induce bronchospasm.

Implementation ⬆ ⬇

PO: Administer with meals to minimize gastric irritation.
- Tablet may be crushed and mixed with food or fluids for patients with difficulty swallowing.
SC: Administer SUBQ injections in lateral deltoid area. Do not use solution if discolored.

IV Administration:

Diluent: May be diluted in D5W, 0.9% NaCl, or 0.45% NaCl.Concentration: 1 mg/mL (undiluted).
Rate: Use infusion pump to ensure accurate dose. Begin infusion at 10 mcg/min. Increase dosage by 5 mcg every 10 min until contractions cease. Maximum dose is 80 mcg/min. Begin to taper dose in 5-mcg decrements after a 30–60 min contraction-free period is attained. Switch to oral dose form after patient is contraction-free 4–8 hr on the lowest effective dose.

Patient/Family Teaching ⬆ ⬇

Instruct patient to take medication as directed. If on a scheduled dosing regimen, take a missed dose as soon as possible; space remaining doses at regular intervals. Do not double doses. Caution patient not to exceed recommended dose; may cause adverse effects, paradoxical bronchospasm, or loss of effectiveness of medication.
- Instruct patient to contact health care professional immediately if shortness of breath is not relieved by medication or is accompanied by diaphoresis, dizziness, palpitations, or chest pain.
- Advise patient to consult health care professional before taking any OTC medications or alcoholic beverages concurrently with this therapy. Caution patient also to avoid smoking and other respiratory irritants.
Preterm Labor: Notify health care professional immediately if labor resumes or if significant side effects occur.

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Pronunciation ⬇

Classifications ⬆ ⬇

Indications ⬆ ⬇