Brethine

Brethine,

trademark for a beta₂ receptor agonist agent (terbutaline sulfate).

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terbutaline sulfate

Brethair, Brethine, Bricanyl

Pharmacologic class: Selective beta₂-adrenergic receptor agonist

Therapeutic class: Bronchodilator

Pregnancy risk category B

Action

Relaxes bronchial smooth muscle by stimulating beta₂-adrenergic receptors; inhibits release of hypersensitivity mediators, especially from mast cells

Availability

Inhaler: 0.2 mg/inhalation

Injection: 1 mg/ml

Tablets: 2.5 mg, 5 mg

⊘Indications and dosages

➣ Bronchospasm in reversible obstructive airway disease

Adults and children older than age 12: 0.25 mg subcutaneously, repeated in 15 to 30 minutes p.r.n., up to a maximum of 0.5 mg in 4 hours. Or 2.5 to 5 mg P.O. q 6 hours t.i.d. while awake, up to a maximum of 15 mg/day in adults; 2.5 mg P.O. q 6 hours t.i.d. while awake, up to a maximum of 7.5 mg/day in children. Or 0.2 to 0.5 mg by inhaler (one to two inhalations) q 4 to 6 hours.

Dosage adjustment

• Renal impairment

Off-label uses

• Tocolytic in preterm labor

Contraindications

• Hypersensitivity to drug, its components, or sympathomimetic amines

Precautions

Use cautiously in:
• cardiovascular disorders, hypertension, arrhythmias, hyperthyroidism, diabetes mellitus, seizure disorders, glaucoma
• concurrent use of MAO inhibitors, tricyclic antidepressants, or beta-adrenergic blockers
• elderly patients
• breastfeeding patients.

Administration

• Inject subcutaneously into lateral deltoid.

Route	Onset	Peak	Duration
P.O.	30 min	2-3 hr	4-8 hr
Subcut.	15 min	30 min	1.5-4 hr
Inhalation	Unknown	Unknown	Unknown

Adverse reactions

CNS: tremors, anxiety, nervousness, insomnia, headache, dizziness, drowsiness, stimulation

CV: palpitations, chest discomfort, tachycardia

GI: nausea, vomiting

Skin: diaphoresis, flushing

Interactions

Drug-drug. Beta-adrenergic blockers: blockage of bronchodilating effect

MAO inhibitors, tricyclic antidepressants: potentiation of terbutaline's adverse cardiovascular reactions

Other sympathomimetic amines: additive adverse cardiovascular reactions

Patient monitoring

• Monitor vital signs.
• Assess neurologic status.

Patient teaching

• Tell patient he may take with or without food.
• Advise patient or parents to establish effective bedtime routine to minimize insomnia.
• Instruct patient or parents to space doses evenly during waking hours, to avoid taking drug at bedtime.
• As appropriate, review all other significant adverse reactions and interactions, especially those related to the drugs mentioned above.