Salmeterol tachyphylaxis in steroid treated asthmatic subjects

Area of Science:

• Pulmonology
• Pharmacology
• Clinical Medicine

Background:

• Tachyphylaxis to salmeterol's protective effects against bronchoconstrictors has been noted in mild asthma patients not on inhaled corticosteroids.
• Salmeterol is clinically recommended for symptomatic asthmatics on inhaled corticosteroids.

Purpose of the Study:

• To investigate airway tachyphylaxis to salmeterol in symptomatic asthma patients receiving inhaled corticosteroids.
• To assess if inhaled corticosteroids prevent tachyphylaxis to salmeterol's bronchodilator and protective effects.

Main Methods:

• A double-blind, randomized study involving 31 adult asthma patients on inhaled corticosteroids.
• Patients received salmeterol (n=22) or placebo (n=9) twice daily for eight weeks.
• Airway responsiveness to methacholine and bronchodilator effects were measured at baseline, 4, and 8 weeks.

Main Results:

• Salmeterol provided significant bronchodilation at all time points without tachyphylaxis.
• Protection against methacholine-induced bronchoconstriction decreased over eight weeks of regular salmeterol use.
• Symptom scores and rescue salbutamol use were significantly reduced during salmeterol treatment.

Conclusions:

• Inhaled corticosteroids did not prevent tachyphylaxis to salmeterol's protective effects against methacholine-induced bronchoconstriction.
• The clinical significance of this reduced protection in patients on inhaled corticosteroids requires further investigation.