Terbutaline

Ethanolamine derivative with selective beta-2 adrenergic activity (bronchodilation, Tocolysis)
Triggers intracellular adenyl cyclase activation with secondary increase in cAMP
1. Bronchial Smooth Muscle relaxation
2. Vascular Smooth Muscle relaxation
3. Reduces Calcium movement across cell membranes resulting in Smooth Muscle relaxation
4. Triggers glycogenolysis and Gluconeogenesis

Subcutaneous
1. Dose: 0.25 mg SQ every 1-4 hours for 24 hours
2. Maximum: 5 mg in 24 hours
Intravenous
1. Start: 10 mcg/minute
2. Increase rate by 5 mcg per minute every 10 minutes
3. Maximum: 25 mcg per minute
4. Once controlled, decrease dose 5 mcg every 30 minutes
5. Titrate dose down to lowest effective dose
Oral (not effective and not recommended)
1. Dose: 2.5 to 7.5 mg PO every 1.5 to 4 hours
2. Hold for maternal pulse >100 beats per minute
Subcutaneous Pump
1. Basal rate: 0.05 to 0.10 mg/hour
2. Boluses: 0.25 mg

Status Asthmaticus
1. Terbutaline may be used as an alternative to the preferred Epinephrine
2. Adult
  1. Dose: 0.25 mg SQ lateral deltoid now (may repeat up to once within 15 to 30 min)
  2. Maximum: 0.5 mg per 4 hours
3. Child (off-label)
  1. Dose: 0.01 mg/kg (up to 0.25 mg) SC every 20 min for up to 3 doses
  2. May be repeated up to every 2-6 hours as needed
Asthma rescue Inhaler
1. Terbutaline was previously available in U.S. as Brethaire Inhaler
2. Had been used as a Short-acting Beta Agonist rescue Inhaler similar to Albuterol

Effective at temporarily stopping contractions
1. Results in shortest hospital triage stays
2. Guinn (1997) Am J Obstet Gynecol 177:814-87 [PubMed]
Oral Terbutaline is not effective in Preterm Labor
1. Lewis (1996) Am J Obstet Gynecol 175:834-7 [PubMed]