Dosing and uses of Brethaire, Brethine (terbutaline)
Adult dosage forms and strengths
tablet
- 2.5mg
- 5mg
injectable solution
- 1mg/mL
Bronchospasm
PO
- Initiate at 2.5 mg three/four times daily PO
- Maintenance: 5 mg three times daily PO q6hr while patient is awake; reduce dose to 2.5 mg q6hr
- Not to exceed 15 mg/Day
SC
- 0.25 mg q15-30min x 3 doses PRN in lateral deltoid
- Not to exceed 0.5 mg/4 hr
Preterm Labor (Off-label)
Initiate at 2.5-5 mcg/min IV
Increase gradually as tolerated at 20-30 minute intervals
Typical effective dose ranges between 17.5-30 mcg/min IV; some require doses up to 70-80 mcg/min
Continue infusion for 12 hr following cessation of uterine contractions; not to exceed 48-72 hr
PO use or prolonged IV use not recommended (see Black box warnings)
Renal Impairment
GFR <50 mL/min: reduce dose by 50%
GFR >50mL/min: Dose adjustment not necessary
Pediatric dosage forms and strengths
tablet
- 2.5mg
- 5mg
injectable solution
- 1mg/mL
Bronchospasm
PO
- <12 years: 0.05 mg/kg three times daily initially; increase PRN, not to exceed 5 mg/day
- 12-15 years: 2.5 mg PO q6hr 3 times daily; not to exceed 7.5 mg/day
- >15 years: 5 mg/dose PO q8hr three times daily; reduce dose to 2.5 mg q6hr; not to exceed 15 mg/24hr
SC (in lateral deltoid)
- <12 years: 0.005-0.01 mg/kg (no more than 0.4 mg) q15-20min x 3; THEN q2-6hour PRN
- >12 years: 0.25 mg q15-30min x 3 doses PRN in lateral deltoid; not to exceed 0.5 mg/4 hr
Brethaire, Brethine (terbutaline) adverse (side) effects
Frequency not defined
Nervousness
Restlessness
Transient hyperglycemia
Transient hypokalemia
Trembling
Tachycardia
HTn
Pounding heartbeat
Dizziness
Lightheadedness
Drowsiness
Headache
Insomnia
Dry mouth
Nausea
Vomiting
Bad taste in mouth
Muscle cramps
Weakness
Diaphoresis
Cardiac arrhythmias
Pulmonary edema
Myocardial ischemia
Myocardial infarction
Increased fetal heart rate
Hypoglycemia in some neonates born to women who received drug during labor
Warnings
Black box warnings
Risk of serious adverse events outweighs potential benefit to pregnant women receiving prlonged treatment with terbutaline injection (ie, >48-72 hr), or acute or prolonged treatment with oral terbutaline
Oral terbutaline should not be used for prevention or any treatment of preterm labor because efficacy has not been established and safety concerns similar to IV administration exist
Death and serious adverse reactions have been reported following prolonged administration of oral or injectable terbutaline to pregnant women
Serious events following prolonged use include tachycardia, transient hyperglycemia, hypokalemia, arrhythmias, pulmonary edema, and myocardial ischemia
Contraindications
Hypersensitivity to sympathomimetics
Use >72 hr in management or prevention of preterm labor
Oral administration in preterm labor
Cautions
Diabetes mellitus
Hypertension
Hyperthyroidism
History of seizures
History of cardiac disease, including ischemic heart disease or associated arrhythmias
Paradoxical bronchoconstriction may occur with excessive use
Fatalities reported with excessive use of sympathomimetics
Optimize anti-inflammatory treatment prior to administering terbutaline for asthma therapy
Beta-2 agonists may increase serum glucose; use caution in patients with diabetes mellitus
Use caution in glaucoma, hyperthyroidism, seizure disorders, and hypokalemia
Pregnancy and lactation
Pregnancy category: C
Lactation: Distributed into breast milk, but in amounts generally considered insufficient to affect nursing infants (AAP Committee states compatible with nursing)
Pregnancy categories
A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.
B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.
C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.
D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.
X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.
NA: Information not available.
Pharmacology of Brethaire, Brethine (terbutaline)
Mechanism of action
Beta adrenergic receptor stimulator causing bronchial/uterine smooth muscle relaxation
Pharmacokinetics
Onset: 30-45 min (PO); 6-15 min (SC)
Duration: 90 min-4 hr
Peak plasma time: 30-60 min
Half-life: 11-16 hr
Protein binding: 25%
Absorbtion: 33-50%
Metabolism: Partially metabolized in liver, mainly to inactive sulfate conjugate
Excretion: 60% urine unchanged, up to 3% feces via bile; remainder in urine as the conjugate (w/ parenteral admin)
Administration
IV Preparation
Solution: dilute as required in D5W (available form: 1 mg/mL)
Administration: use infusion pump
Protect inj from light
Do not use if discolored
