Introduction: The use of inhaled drugs through metered-dose inhaler has been advocated for years. Nonetheless, a small number of patients are routinely treated by this technique. Prescriptions of inhaled drugs by healthcare providers are not frequent, usually because they anticipate patients will not be able to perform the technique correctly. In addition, healthcare providers do not usually take their time to appropriately teach patients how to use metered-dose inhalers correctly. Objective: To evaluate the percentage of uninstructed patients that learn how to use a metered-dose inhaler correctly after being taught by a pneumologist. Patients and methods: One hundred and nineteen patients from a private clinic were prospectively studied in São Paulo, southeastern Brazil. Patients were exhaustively taught how to use the metered-dose inhaler at the first consultation and were told to return after 10 days, when they were asked to perform the technique exactly the way they were doing it at home. Their performance was classified as correct, slightly incorrect, intermediately incorrect, and totally incorrect. Results: Twenty-six patients were excluded for not coming to the second appointment. The final sample comprised 93 patients. Age ranged from 9 to 81 years (mean age 42.6 ± 21); 59.2% of the patients were male and 40.8% female. Considering all patients, only 16.25 of them used the metered-dose inhaler totally incorrectly and 19.3% performed the technique intermediately incorrectly. The most frequent mistakes were: metered-dose inhaler device was placed inside the mouth; inspiration before jet was activated; fast aspiration; inspiration through the nose. Thirty-three percent of patients who were under 15 and over 75 years performed the technique correctly. Conclusion: This study has demonstrated that the majority of the patients learned how to use the metered-dose inhaler correctly after being properly and extensively taught.

Keywords: Nebulizers and vaporizers. Inhalation administration. Learning.