What are the potential interactions of Ascoril LS (levosalbutamol) syrup with other medications?

Drug Interactions of Ascoril LS Syrup

Ascoril LS syrup, containing levosalbutamol (a beta-2 agonist bronchodilator), has several clinically significant drug interactions that require careful monitoring, particularly with beta-blockers, diuretics, digoxin, MAO inhibitors, and tricyclic antidepressants. 1

Critical Contraindications and High-Risk Interactions

Beta-Blockers

• Beta-adrenergic blocking agents are contraindicated in asthmatic patients taking levosalbutamol as they not only block the pulmonary effects but may produce severe bronchospasm 1
• If beta-blockers are absolutely necessary (e.g., post-myocardial infarction prophylaxis), only cardioselective beta-blockers should be considered and administered with extreme caution 1

MAO Inhibitors and Tricyclic Antidepressants

• Levosalbutamol must be administered with extreme caution in patients taking MAO inhibitors or tricyclic antidepressants, or within 2 weeks of discontinuing these agents 1
• The vascular effects of levosalbutamol may be significantly potentiated through these interactions 1
• Consider alternative bronchodilator therapy in patients requiring these psychiatric medications 1

Cardiovascular Drug Interactions

Digoxin

• Levosalbutamol can decrease serum digoxin levels by 16-22% based on studies with racemic albuterol 1
• Carefully evaluate and monitor serum digoxin levels in patients receiving chronic digoxin therapy when initiating levosalbutamol 1
• Dose adjustments of digoxin may be necessary to maintain therapeutic levels 1

Diuretics (Non-Potassium-Sparing)

• Loop and thiazide diuretics can cause ECG changes and hypokalemia that are acutely worsened by beta-agonists, especially when recommended doses are exceeded 1
• Monitor potassium levels regularly when co-administering levosalbutamol with non-potassium-sparing diuretics 1
• The clinical significance increases when beta-agonist doses exceed recommendations 1

Other Bronchodilator Interactions

Short-Acting Sympathomimetics

• Avoid concomitant use of other short-acting sympathomimetic bronchodilators or epinephrine with levosalbutamol 1
• If additional adrenergic drugs must be administered by any route, use with extreme caution to avoid deleterious cardiovascular effects 1
• This includes over-the-counter decongestants and cold preparations containing sympathomimetics 1

Metabolic and Pharmacokinetic Considerations

Metabolism Profile

• Levosalbutamol is metabolized almost exclusively by sulphotransferase (SULT) 1A3 to inactive metabolites 2
• The R-enantiomer (levosalbutamol) is metabolized up to 12 times faster than the S-enantiomer 2
• Genetic polymorphisms in SULT1A3 and beta-2 adrenoceptors can affect drug disposition and response, explaining interindividual variations in pharmacokinetic-pharmacodynamic relationships 2

Cardiovascular Effects Monitoring

• Mean heart rate increases of 0.8-10.9 bpm have been documented 30 minutes after dosing in pediatric patients 1
• Heart rate typically returns to baseline within 60 minutes and shows no significant elevation after 21 days of treatment 1
• In COPD patients with concurrent coronary heart disease, heart rate increased from 64.4 to 72.7 beats/min at 20 minutes but returned to baseline by 60 minutes, with no cumulative effect after 7 days 3

Common Pitfalls and Clinical Caveats

• Do not assume all beta-agonists are interchangeable: Levosalbutamol has distinct pharmacokinetic properties compared to racemic salbutamol 2, 4
• Avoid overlooking over-the-counter medications: Many cold preparations contain sympathomimetics that can interact 1
• Monitor for cumulative effects: While acute heart rate changes resolve quickly, patients with cardiovascular disease require closer monitoring 3
• Consider timing of gastric pH: Approximately 6% of levosalbutamol undergoes acid-catalyzed racemization in the stomach, though this is generally not clinically significant 2

Special Population Considerations

Patients with Cardiovascular Disease

• In patients with COPD concurrent with coronary heart disease, levosalbutamol demonstrated no sustained negative cardiovascular effects over 7 days of treatment 3
• However, initial heart rate monitoring is essential, particularly in the first hour after administration 3

Pediatric Patients

• Metabolic effects include mean glucose increases of 4.9-10.8 mg/dL and potassium decreases of 0.27-0.56 mEq/L at therapeutic doses 1
• These changes are generally not clinically significant but warrant monitoring in patients with diabetes or electrolyte abnormalities 1