Terbutaline stimulates intracellular adenyl cyclase, the enzyme that catalyzes the conversion of ATP to cyclic- 3', 5'-adenosine monophosphate (cAMP), resulting in relaxation of bronchial smooth muscle and inhibition of release of mediators of immediate hypersensitivity from mast cells.

Adult
PO
Acute bronchospasm. Initial: 2.5 mg or 3 mg tid, up to 5 mg tid as necessary. As modified-release tab: 5 mg or 7.5 mg bid.

Inhalation
Acute bronchospasm - metered-dose powd inhaler: 250-500 mcg as required. Max: 2,000 mcg/day.
Severe bronchospasm - 1% nebulizer soln: 2.5-10 mg 2-4 times/day.

IM/IV/SC
Severe bronchospasm 250-500 mcg up to 4 times/day by SC, IM or IV inj, or by IV infusion as a soln containing 3-5 mcg/mL at a rate of 0.5-1 mL/min.

Adverse drug reactions: tachycardia, nervousness, tremor, palpitations, dizziness, headache, nausea, vomiting, anxiety, restlessness, weakness, flushes, sweating, chest discomfort.

Adapted from CIMS Drug Information System. Internet. Accessed on January 10, 2016.