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Peer reviewed clinical letter

Vol. 145 No. 3132 (2015)

Stop using the flotation technique and start weighing salbutamol pressurised metered-dose inhalers without dose counters

  • Ermindo R. Di Paolo
  • Stéphanie Spaggiari
  • André Pannatier
  • Farshid Sadeghipour
  • Isabelle Rochat
  • Gaudenz M Hafen
Cite this as:
Swiss Med Wkly. 2015;145:w14162


Salbutamol pressurised metered-dose inhalers (pMDIs) are not equipped with dose counters outside the USA. The aim of this study was to describe a simple reproducible method for determining the number of doses remaining in a pMDI based on scale weight. With a laboratory scale, the mean weight of the canisters was 28.61 ± 0.10 g after priming and 14.84 ± 0.23 g after 200 puffs. Similar results were obtained with two common digital scales. We recommend weighing salbutamol canisters on a common digital scale, and replacing an old pMDI with a new one when the weight falls to ≤15 g.


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