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Urinary Excretion Post Inhalation Method to Correlate Inhaler Technique with Disease Control in Patients with Obstructive Pulmonary Diseases Using Own Metered Dose Inhaler (MDI)
  • ethirajan nandagopal,
  • Sumithra M,
  • N Meenakshi
ethirajan nandagopal

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Sumithra M
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N Meenakshi
Chettinad Health City
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Objectives: Correct use of inhaler devices is critical in ensuring the optimal lung bioavailability of the inhaled drug. The study aimed to assess inhaler technique used in patients with using metered-dose inhalers (MDI) by correlating with urinary salbutamol excretion post inhalation and its correlation with disease control. Methods: Thirty patients with obstructive pulmonary diseases attending outpatients’ services inhaled two doses of salbutamol 100 µg and urine samples were collected after 30 min. Inhaler technique scores were assessed using a standardized 8-point checklist. The 30-minute concentration of urinary salbutamol is then correlated with inhaler technique scores and control status of the disease. Key findings: The mean age of the subjects was 60.8 (SD ± 9.338). The mean (SD) 30 min urinary salbutamol concentration was 3.6±1.6 µg/ml. The mean concentration of salbutamol was found to be 2.3 µg/ml (n=1), 2.3 µg/ml (n=5), 3.1 µg/ml (n=7), 3.9 µg/ml (n=8), 4.7 µg/ml (n=5), 5.3 µg/ml (n=3), and 5.0 µg/ml (n=1) among patients performing 1, 2, 3, 4, 5, 6, 7, 8 steps correctly, respectively. There was a statistically significant correlation (p=0.028) witnessed between the mean 30 min urinary salbutamol concentration and total correct steps. The frequency of exacerbation, use of antibiotics, and oral corticosteroids (OCS) were more in patients with poor inhaler technique scores, although statistical significance was achieved only for frequency of antibiotics use (p=0.032). Conclusions: The 30 min salbutamol urinary concentration evaluation may help to identify patients who were underdosed due to poor handling of inhaler devices. Being a complex procedure, it can at least be initiated in patients reporting frequent exacerbations, hospitalization, and those who need multiple drugs for disease control.