Do levosalbutamol (Levalbuterol) and terbutaline increase the risk of tachycardia in infants?

From the Guidelines

Levosalbutamol and terbutaline should be used with caution in infants due to the risk of tachycardia, with levosalbutamol being the preferred option due to its more selective action on beta-2 receptors and lower risk of cardiovascular side effects. When treating infants with bronchodilators, it is essential to consider the potential risks and benefits, as the evidence suggests that these medications may not provide significant benefits in the clinical course of infants with bronchiolitis 1. The American Academy of Pediatrics recommends against the use of bronchodilators, including albuterol and salbutamol, in infants with bronchiolitis, citing the lack of evidence for their effectiveness and the potential for adverse effects such as tachycardia and tremors 1.

Some key points to consider when using levosalbutamol and terbutaline in infants include:

• Levosalbutamol is the active R-isomer of albuterol and works at lower doses than racemic albuterol or terbutaline
• Typical levosalbutamol dosing is 0.31-1.25 mg via nebulization every 4-6 hours as needed
• Terbutaline is generally dosed at 0.1-0.3 mg/kg/dose (maximum 5 mg) every 6 hours
• Careful monitoring of heart rate, oxygen saturation, and respiratory status is essential when administering either medication to infants
• The mechanism behind the reduced cardiovascular effects of levosalbutamol relates to its enhanced receptor specificity, avoiding the beta-1 cardiac stimulation that contributes to tachycardia 1.

In situations where tachycardia is a particular concern, such as in infants with congenital heart disease or those already experiencing tachycardia, levosalbutamol would be the more appropriate choice due to its lower risk of cardiovascular side effects 1. However, it is crucial to weigh the potential benefits and risks of using these medications in infants and to consider alternative treatment options, as the evidence suggests that bronchodilators may not provide significant benefits in the clinical course of infants with bronchiolitis.

From the FDA Drug Label

The expected symptoms with overdosage are those of excessive beta-adrenergic stimulation and/‌or occurrence or exaggeration of any of the symptoms listed under ADVERSE REACTIONS, e.g., seizures, angina, hypertension or hypotension, tachycardia with rates up to 200 beats per minute, arrhythmias, nervousness, headache, tremor, dry mouth, palpitation, nausea, dizziness, fatigue, malaise, and insomnia. Increased fetal heart rate and neonatal hypoglycemia may occur as a result of maternal administration

Tachycardia Risk in Infants:

• The FDA drug label for terbutaline mentions that tachycardia is a possible symptom of overdosage, with rates up to 200 beats per minute 2.
• Additionally, increased fetal heart rate may occur as a result of maternal administration of terbutaline 2.
• However, there is no direct information in the provided drug labels that compares the risk of tachycardia in infants between levosalbutamol and terbutaline.
• Therefore, based on the available information, it is unclear whether levosalbutamol and terbutaline have a higher risk of tachycardia in infants.

From the Research

Tachycardia Risk in Infants

• The risk of tachycardia in infants associated with levosalbutamol and terbutaline is a concern in the treatment of acute bronchospasm.
• A study from 1996 3 compared the efficacy and side effects of salbutamol, terbutaline, and fenoterol in asthmatic children, finding that all three drugs caused an increase in heart rate, with salbutamol and fenoterol causing a more significant increase than terbutaline.
• Another study from 2023 4 investigated the acute effects of salbutamol and ipratropium on heart rates in patients with obstructive airway disease, finding a significant increase in heart rates after salbutamol administration.
• However, a study from 1998 5 compared the efficacy of terbutaline administered by nebulizer or metered-dose inhaler and spacer device in infants with acute wheezing, finding no difference in the rate of improvement in clinical score between the two groups, but did not specifically address the risk of tachycardia.
• A study from 1993 6 found no clear connection between inhaled bronchodilators, including terbutaline, and arrhythmias in patients with COPD and ischemic heart disease.
• A study from 2014 7 suggested that early administration of terbutaline in severe pediatric asthma may reduce the incidence of acute respiratory failure, but did not specifically address the risk of tachycardia in infants.

Comparison of Bronchodilators

• The studies suggest that salbutamol and terbutaline are effective bronchodilators, but may have different side effect profiles, including the risk of tachycardia.
• The choice of bronchodilator and delivery method may depend on individual patient factors, including the severity of asthma and the presence of underlying heart disease.
• Further research is needed to fully understand the risks and benefits of levosalbutamol and terbutaline in infants and to determine the optimal treatment approach for acute bronchospasm in this population.