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 to treat and prevent reversible bronchospasm in patients with asthma under the age of 12 who also have 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 orally The recommended dosage is 3 times day (about every 6 hours); if side effects develop, reduce the amount to 2.5 mg 3 times daily. The maximum dose is 15 mg/24 hours.

• SubQ:

  • For a maximum of three dosages, 0.25 mg subcutaneous may be repeated every 20 minutes: 0.75 mg every hour

• 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.
  • No more than six inhalations should be required in a 24-hour period.
• Note:
  • The patient should be evaluated again right away if previously effective dose does not provide enough relief or if the effects of inhalation linger longer than three hours.
  • May be a sign of asthma worsening.

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

• Large extravasations:

  • Apply a solution of 1 mg diluted in 10 mL of 0.9% sodium chloride to the extravasation location.
  • The amount of terbutaline solution provided ranged from 3 to 10 mL.

• Small/ distal extravasations:

  • Use a solution of 1 mg diluted in 1 mL of 0.9% sodium chloride to infiltrate the extravasation area.
  • The amount of terbutaline solution given out ranged 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, gradually increased by 2.5 to 5 mcg/minute every 20 to 30 minutes, with a maximum dose of 25 mcg/minute; after contractions are under control, reduce to the lowest effective dose.
• SubQ: 0.25 mg every 20 to 3 hours while holding for a pulse greater than 120 beats per minute
• Long-term tocolysis has not been approved for terbutaline (beyond 48 to 72 hours)

Terbutaline dose in Children

Terbutaline dose in the treatment of acute exacerbation of Asthma:

• Continuous infusion:

• Availability of data is limited, the ideal dose is not known, and efficacy outcomes can vary.:

  • Children and Adolescents:

    • Initial: IV bolus dose: 4 to 10 mcg/kg followed by 0.2 to 0.4 mcg/kg/minute of continuous infusion; titrate as often as every 30 minutes depending on patient response or toxicity.
    • Although 10 mcg/kg/minute doses have been documented, the typical maximum dose is 5 mcg/kg/minute.

• Oral Dose:

  • Children ≥12 and Adolescents <15 years:

    • 5 mg orally The maximum daily dose is 7.5 mg, taken three times per day.

  • Adolescents ≥15 years:

    • If side effects develop, lower the dose to 2.5 mg three times daily; the maximum daily dose is 15 mg/24 hours. 5 mg per mouth, three times daily (about every 6 hours).

• Subcutaneous:

  • Children: Limited data available:

    • For three doses, administer 0.01 mg/kg/dose subcutaneously every 20 minutes; as necessary, repeat every 2 to 6 hours.

  • Adolescents:

    • Up to three doses of 0.25 mg/dose subcutaneous may be given every 20 minutes.

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

  • Children ≥6 years and Adolescents:

    • If after five minutes the first inhalation (0.5 mg) is still ineffective, repeat the dose.
    • If the second dose is ineffective, speak with a medical professional right away.
    • There is a six-inhalation limit per day.

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]

• Pregnant women frequently have adverse effects such as arrhythmias, increased heart rate, temporary hyperglycemia, hypokalemia, myocardial infarction, and pulmonary embolism.
• For a brief period of time (48 hours), tocolytics can prolong pregnancy and enable the administration of prenatal steroids. Before foetal viability, they shouldn't be used.
• The FDA has not given terbutaline its approval 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:

The manufacturer's labelling does not mention dosage modifications.

Terbutaline Dose adjustment in liver disease:

The manufacturer's labelling does not mention dosage modifications.

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:

• Intolerance to terbutaline, sympathomimetic medicines, amines, or any other formulation ingredient

Additional contraindications

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

Bricanyl Turbuhaler [Canadian product]:

• Tachyarrhythmias
• In patients who are at a high risk of early labour or threatening termination, as a tocolytic.

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:

• To encourage minimal volatility in peak and trough blood levels, administer continuously.

Inhalation:

• Bricanyl Turbuhaler [Canadian product]:
  • The patient should hold the inhaler upright after removing the lid. He or she should then turn the blue grip as far as it will go in one direction before turning it back to the starting position.
  • The inhaler is ready to use when it makes a clicking noise.
  • The patient should thoroughly exhale, but not into the inhaler, before placing the mouthpiece between teeth, sealing their lips around the inhaler, and taking a deep breath.
  • After inhaling, the mouth should be regularly cleansed.
  • The outside of the mouthpiece should be wiped with a dry cloth once a week, and the inhaler should be kept dry.
  • There are 20 doses left when a red mark first appears in the dose-indicator pane (under the mouthpiece).
  • When the red mark hits the bottom of the dose indicator, the terbutaline should be thrown away.

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.
  • Terbutaline solution 1 mg diluted in 10 mL (for large extravasation sites) or 1 mg diluted in 1 mL (for tiny extravasation sites) of 0.9% sodium chloride should be applied to the extravasation area.

Mechanism of action of Terbutaline:

The uterine and bronchial smooth muscles relax as a result of the beta-receptor agonist terbutaline.

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: