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

From the Guidelines

Levosalbutamol is generally preferred over terbutaline in infants due to its lower risk of causing tachycardia, as it has greater beta-2 selectivity with less beta-1 activity. When treating bronchospasm in infants, levosalbutamol (also known as levalbuterol) is often the preferred choice because it is the active R-enantiomer of albuterol, which provides bronchodilation with fewer cardiovascular side effects 1. Typical dosing for nebulized levosalbutamol in infants is 0.075 mg/kg (minimum dose 1.25 mg) every 20 minutes for 3 doses, then 0.075–0.15 mg/kg up to 5 mg every 1–4 hours as needed 1.

Key Considerations

• Terbutaline, a non-selective beta-agonist, tends to cause more cardiovascular stimulation, including tachycardia, due to its effects on beta-1 receptors in the heart.
• If medication is needed, using the lowest effective dose, monitoring heart rate during administration, and ensuring proper delivery technique with age-appropriate devices (such as a face mask with nebulizer for infants) can help minimize tachycardia risk.
• For infants with underlying cardiac conditions or those already experiencing tachycardia, consultation with a pediatric pulmonologist or cardiologist is recommended before administering either medication.

Administration and Monitoring

• The method of administration is an important consideration, with delivery from an MDI and spacer having several advantages over nebulization, including shorter administration time and no requirement for adjustment of ventilator flow or cooling of gases 1.
• Monitoring of heart rate and other vital signs during administration is crucial to quickly identify any adverse effects, such as tachycardia.
• Ensuring proper delivery technique with age-appropriate devices is vital for effective treatment and minimization of side effects.

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

• There is no direct evidence in the provided studies that compares the risk of tachycardia in infants between levosalbutamol and terbutaline.
• However, the studies suggest that levosalbutamol, the R-enantiomer of salbutamol, is the therapeutically active isomer with all the beta 2 agonist activity 3.
• The use of racemic salbutamol, which contains both R and S isomers, may lead to higher and sustained plasma levels of S-salbutamol with repeated dosing, potentially causing deleterious effects 3.
• The studies do not provide information on the specific risk of tachycardia in infants associated with levosalbutamol or terbutaline, but they do discuss the importance of beta 2 agonists in the treatment of asthma and COPD 4, 5, 6.
• It is worth noting that the provided studies focus on the treatment of asthma and COPD in adults and children, but do not specifically address the risk of tachycardia in infants 4, 3, 7, 5, 6.