Terbutaline (Bricanyl) is a beta-receptor agonist. It acts on the smooth muscles of the airways and the uterus. It is, therefore, primarily used for the management of asthma.

Indications of Terbutaline:

• Asthma/ Bronchospasm:

  • It is used for the prevention and reversal of bronchospasm in patients ≥12 years of age with asthma and reversible bronchospasm associated with bronchitis and emphysema

• Off Label Use of Terbutaline in Adults:

  • Extravasation management,
  • Sympathomimetic vasoconstrictors
  • Acute (short-term) treatment of Premature labor tocolysis)

Terbutaline dose in Adults

Terbutaline dose in the treatment of Asthma and bronchospasm:

• Oral:

  • 5 mg per oral 3 times daily (approximately every 6 hours);
  • reduce dose to 2.5 mg 3 times daily if side effects occur
  • The maximum dose is: 15 mg/24 hours

• SubQ:

  • 0.25 mg subcutaneous;
  • may repeat every 20 minutes for 3 doses
  • maximum: 0.75 mg/1-hour period

• Manufacturer's labeling:

  • Dosing in the prescribing information may not reflect current clinical practice.
  • 0.25 mg/dose;
  • may repeat in 15 to 30 minutes
  • The maximum dose: 0.5 mg/4 hour period)

• Inhalation: Bricanyl Turbuhaler [Canadian product]:

  • One inhalation (0.5 mg) as needed.
  • The dose should be repeated if not effective after 5 minutes.
  • Consult a healthcare provider immediately after the second dose if the desired response is not achieved.
  • Not more than 6 inhalations in a 24 hour period should not be needed.
• Note:
  • If adequate relief is not obtained with previously effective dose, or if effects of inhalation last <3 hours, the patient should be reassessed promptly;
  • may indicate worsening asthma.

Terbutaline dose in the treatment of Extravasation management, sympathomimetic vasoconstrictors:

• Large extravasations:

  • Infiltrate extravasation area using a solution of 1 mg diluted in 10 mL of 0.9% sodium chloride;
  • The volume of terbutaline solution administered varied from 3 to 10 mL.

• Small/ distal extravasations:

  • Infiltrate extravasation area using a solution of 1 mg diluted in 1 mL of 0.9% sodium chloride;
  • The volume of terbutaline solution administered varied from 0.5 to 1 mL.

Terbutaline dose in the treatment dose of Premature labor (acute short-term [≤72 hours] treatment of tocolysis) (off-label):

• 2.5 to 5 mcg/minute intravenous, increased gradually every 20 to 30 minutes by 2.5 to 5 mcg/minute up to a maximum of 25 mcg/minute;
• decrease to the lowest effective dose once contractions are controlled.
• SubQ: 0.25 mg every 20 minutes to 3 hours;
• hold for pulse >120 beats per minute.
• Terbutaline has not been approved for prolonged tocolysis (beyond 48 to 72 hours)

Terbutaline dose in Childrens

Terbutaline dose in the treatment of acute exacerbation of Asthma:

• Continuous infusion:

• Limited data available, optimal dose not defined, efficacy results variable:

  • Children and Adolescents:

    • Initial: IV bolus dose: 4 to 10 mcg/kg followed by continuous infusion of 0.2 to 0.4 mcg/kg/minute, titrate by 0.1 to 0.2 mcg/kg/minute increments as frequently as every 30 minutes based on patient response or toxicity.
    • The usual maximum dose is 5 mcg/kg/minute; however, doses as high as 10 mcg/kg/minute have been described.

• Oral Dose:

  • Children ≥12 and Adolescents <15 years:

    • 5 mg per oral three times a day
    • the maximum daily dose is 7.5 mg

  • Adolescents ≥15 years:

    • 5 mg per oral thrice daily (approximately every 6 hours);
    • reduce dose to 2.5 mg three times daily if side effects occur maximum daily dose: 15 mg/24 hours.

• Subcutaneous:

  • Children: Limited data available:

    • 0.01 mg/kg/dose subcutaneous every 20 minutes for 3 doses; may repeat every 2 to 6 hours as needed.

  • Adolescents:

    • 0.25 mg/dose subcutaneous may repeat every 20 minutes for up to 3 doses.

• Terbutaline Inhaler: Oral inhalation: Canadian labeling: Bricanyl Turbuhaler [Canadian product]

  • Children ≥6 years and Adolescents:

    • 1 inhalation (0.5 mg) as needed; if not effective after 5 minutes may repeat dose.
    • If the second dose is not effective, consult a health care provider immediately.
    • Maximum daily dose: 6 inhalations/24 hours.

Pregnancy Risk Category: C

• Studies on animal reproduction revealed negative outcomes.
• It crosses the placenta so it is not recommended for pregnant women.

[US Boxed Warning]

• Arrhythmias, elevated heart rate, hyperglycemia transient, hypokalemia, myocardial infarction, and pulmonary embolism are all common adverse events in pregnant women.
• Tocolytics can be used to prolong pregnancy for a short time (48 hours) and allow for administration of antenatal steroids. They should not be used before fetal viability.
• Terbutaline has not been approved by the FDA for long-term tocolysis (>48 hours to 72 hours)..

Terbutaline use during breastfeeding:

• Breast milk contains Terbutaline.
• Manufacturer recommends that terbutaline not be used by breastfeeding mothers unless the benefits to the mother are greater than the risks to the infant.

Terbutaline Dose adjustment in renal disease:

There are no dosage adjustments provided in the manufacturer's labeling.

Terbutaline Dose adjustment in liver disease:

There are no dosage adjustments provided in the manufacturer's labeling.

Common Side Effects of Terbutaline:

• Central Nervous System:

  • Nervousness
  • Restlessness

• Endocrine & Metabolic:

  • Decreased Serum Potassium
  • Increased Serum Glucose

• Neuromuscular & Skeletal:

  • Tremor

Rare Side Effects of Terbutaline:

• Cardiovascular:

  • Hypertension
  • Tachycardia

• Central Nervous System:

  • Dizziness
  • Drowsiness
  • Headache
  • Insomnia

• Dermatologic:

  • Diaphoresis

• Gastrointestinal:

  • Dysgeusia
  • Nausea
  • Vomiting
  • Xerostomia

• Neuromuscular & Skeletal:

  • Muscle Cramps
  • Weakness

Contraindications to Terbutaline:

• Hypersensitivity to terbutaline, sympathomimetic drugs amines or any other component of the formulation

Additional contraindications

• Tocolysis that lasts for more than 48 to 72 hours.

Bricanyl Turbuhaler [Canadian product]:

• Tachyarrhythmias
• As tocolytic in patients at high risk of premature labor/threatened termination.

Warnings and precautions

• Hypersensitivity reactions

  • Hypersensitivity reactions can be immediate, including rash, angioedema and urticaria.

• Asthma

  • For stabilization of asthma, it should be used with an anti-inflammatory agent.

• Cardiovascular disease

  • Terbutaline can increase heart rate, as well as increase the risk of hypertension or arrhythmias.

• Diabetes:

  • Monitoring is important because beta-agonists can increase serum glucose.

• Glaucoma:

  • Glaucoma patients should be cautious when using it.

• Hyperthyroidism:

  • Hyperthyroidism should be treated with caution.

• Hypokalemia

  • Serum potassium may be decreased by beta-agonists

• Seizures:

  • Beta-agonists can cause CNS stimulation so it is important to be cautious when using them.

Terbutaline: Drug Interaction

Monitoring parameters:

• Pulse/BP
• Blood glucose
• Serum potassium
• Pulmonary function tests
• Signs/symptoms of pulmonary edema

How to administer Terbutaline?

An infusion pump should be used for intravenous administration.

Oral:

• Administer around-the-clock to promote less variation in peak and trough serum levels

Inhalation:

• Bricanyl Turbuhaler [Canadian product]:
  • After removing the lid, patient should hold the inhaler upright and turn blue grip as far as it will go in one direction then turn it back to the original position.
  • Clicking sound shows that the inhaler is ready for use.
  • The patient should exhale fully but not into the inhaler and then place mouthpiece gently between teeth, close lips around inhaler and inhale deeply.
  • The mouth should be regularly washed after inhalation.
  • The inhaler should be kept dry and outside of mouthpiece should be cleaned once weekly with a dry tissue.
  • The first appearance of a red mark in the dose-indicator (window underneath mouthpiece) indicates that 20 doses remain.
  • Terbutaline should be discarded when the red mark reaches bottom of dose indicator.

Subcutanous:

• Extravasation management, sympathomimetic vasopressors (off-label use):
  • The infusion should be immediately stopped and the extravasated solution should be gently aspirated from the IV line without flushing the line.
  • The extremity should be elevated and canula should be removed.
  • Extravasation area should be infiltrated with terbutaline solution 1 mg diluted with 10 mL (large extravasation site) or 1 mg diluted in 1 mL (small extravasation site) of 0.9% sodium chloride.

Mechanism of action of Terbutaline:

Terbutaline is a beta-receptor agonist that causes smooth muscle relaxation in the uterine and bronchial areas.

The beginning of action:

• Oral: 30-45 minutes
• Subcutaenous: 6-15 minutes
• Inhalation: 5 min (maximum effect 15-60 minutes).

Duration:

• Oral: 4 to 8 hours
• Oral inhalation: 3 to 6 hours
• SubQ: 1.5 to 4 hours

Absorption:

• 33% to 50%

Protein binding:

• 25%

Metabolism:

• Occurs in the liver to inactive sulfate conjugates

Bioavailability:

• SubQ doses are more bioavailable than oral

Half-life elimination:

• 5.7 hours (range: 2.9 to 14 hours)

Time to reach peak serum concentration:

• SubQ: 0.5 hours

Excretion:

• Occurs in urine (60% as unchanged drug); feces

International Brands of Terbutaline:

• Aironyl
• Asmaline
• Asthmasian
• Ataline
• Beta-2
• Betamic
• Brethin
• Bricalin
• Bricanil
• Bricanyl
• Bricanyl Depot
• Bricanyl EX
• Bricanyl Turbuhaler
• Bricasma
• Bricasol
• Britaline
• Bronchodam
• Bronclyn
• Bronco Asmo
• Bronconyl
• Brothine
• Bucanil
• Bucaril
• Butaline
• Contimit
• Dilanyl
• Draconyl
• Getran
• Glin
• Nairet
• Nairex
• Neoterb
• Pulmoxel
• Samisil
• Talin
• Tebif
• Terbasmin
• Terbron
• Terbu Expectorant
• Terbul
• Terbulin
• Terburop
• Terbutalin AL
• Terbutalin Stada
• Terbutanyl
• Terbutil
• Tervent

Terbutaline Brands in Pakistan: