Metered-dose inhaler adherence in a clinical trial

C. S. Rand, R. A. Wise, M. Nides, M. S. Simmons, E. R. Bleecker, J. W. Kusek, V. C. Li, D. P. Tashkin

Research output: Contribution to journalArticlepeer-review

301 Scopus citations


We studied patterns of inhaler usage in a sample of participants from two centers in the Lung Health Study clinical trial. The inhaler, containing either ipratropium bromide or a placebo, was prescribed to be taken as two inhalations three times daily. For 4 months we recorded adherence by both self-report (n = 95) and canister weight change (n = 70). We compared these results with data obtained from a microprocessor monitoring device, the Nebulizer Chronolog (NC), which records the date and time of each inhaler actuation. Seventy-three percent of the participants reported using the inhaler an average of three times daily; however, NC data showed that only 15% of the participants actually used the inhaler an average of 2.5 or more times per day. Canister weight overestimated adherence because only 62% of the NC sets contained the prescribed two actuations. Fourteen percent showed a pattern of actuation of their inhalers more than 100 times in a 3-h interval. We interpret this usage pattern to reflect deliberate emptying of inhalers to appear to be in good compliance with the prescribed program. We conclude that self-report and weighing of inhaler canisters overestimate adherence to the prescribed regimens. Furthermore, a substantial number of monitored inhaler users appear to deliberately dump their medication prior to follow-up visits.

Original languageEnglish (US)
Pages (from-to)1559-1564
Number of pages6
JournalAmerican Review of Respiratory Disease
Issue number6
StatePublished - 1992
Externally publishedYes

ASJC Scopus subject areas

  • Pulmonary and Respiratory Medicine


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