Selective ?2-adrenoceptor stimulant relax bronchial smooth muscle, thereby relieving bronchospasm. This action may result from increased production of cAMP and ensuing reduction in intracellular calcium concentration caused by activation of the enzyme adenylate cyclase that catalyzes the conversion ATP to cAMP. Increased cAMP concentrations, in addition to relaxing bronchial smooth muscle, inhibit release of mediators of immediate hypersensitivity from cells, especially from mast cells.

Dosage ; Dosing: Adult

Asthma or bronchoconstriction:

Oral: 5 mg/dose every 6 hours 3 times/day; if side effects occur, reduce dose to 2.5 mg every 6 hours; not to exceed 15 mg in 24 hours.

SubQ: 0.25 mg/dose; may repeat in 15-30 minutes (maximum: 0.5 mg/4-hour period)

Bronchospasm (acute): Inhalation (Bricanyl® [CAN] MDI: 500 mcg/puff, not labeled for use in the U.S.): One puff as needed; may repeat with 1 inhalation (after 5 minutes); more than 6 inhalations should not be necessary in any 24 hour period. Note: If a previously effective dosage regimen fails to provide the usual relief, or the effects of a dose last for >3 hours, medical advice should be sought immediately; this is a sign of seriously worsening asthma that requires reassessment of therapy.

Premature labor (acute; short-term [≤72 hours] tocolysis; unlabeled use):

I.V.: 2.5-5 mcg/minute; increased gradually every 20-30 minutes by 2.5-5 mcg/minute; effective maximum dosages from 17.5-30 mcg/minute have been used with caution. Duration of infusion is at least 12 hours (Travis, 1993).

SubQ: 0.25 mg every 20 minutes to 3 hours; hold for pulse >120 beats per minute. Terbutaline has not been approved for and should not be used for prolonged tocolysis (beyond 48-72 hours) (ACOG, 2003)

Dosing: Pediatric

(For additional information see "Terbutaline: Pediatric drug information" )

Asthma or bronchoconstriction:

Oral: Children:

<12 years: Initial: 0.05 mg/kg/dose 3 times/day, increased gradually as required; maximum: 0.15 mg/kg/dose 3-4 times/day or a total of 5 mg/24 hours

12-15 years: 2.5 mg every 6 hours 3 times/day; not to exceed 7.5 mg in 24 hours

>15 years: 5 mg/dose every 6 hours 3 times/day; if side effects occur, reduce dose to 2.5 mg every 6 hours; not to exceed 15 mg in 24 hours

SubQ: Children:

<12 years: 0.005-0.01 mg/kg/dose to a maximum of 0.4 mg/dose; may repeat in 15-20 minutes

≥12 years: Refer to adult dosing.

Bronchospasm (acute): Inhalation: Bricanyl® [CAN] MDI: 500 mcg/puff, not labeled for use in the U.S.): Children ≥6 years: Refer to adult dosing.

Dosing: Geriatric

Refer to adult dosing