Dose counting and the use of pressurized metered-dose inhalers: running on empty.
BACKGROUND
Pressurized metered-dose inhalers (pMDIs) are the cornerstone of asthma treatment. The pMDI is an economic and portable medication delivery system, but the device does not indicate how much medicine remains in the canister once a patient starts using it.


OBJECTIVE
To determine how patients evaluate the contents of their pMDI and whether they are either discarding inhalers when medication remains or using inhalers beyond the indicated number of doses.


METHODS
This study was conducted in April 2003 via a 6.5-minute telephone interview with a random sample of 500 families with asthma from across the United States.


RESULTS
Of the 500 respondents participating in the telephone interview, nearly one third (31.6%) named an inhaled corticosteroid or bronchodilator and inhaled corticosteroid combination as the inhaler used when wheezing, coughing, or short of breath. Respondents using a bronchodilator (n = 342) varied in the frequency with which they use their pMDIs: 31.9% daily, 18.7% weekly, 23.4% monthly, and 23.1% less than once per month. More than half (53.8%) of bronchodilator users refill their prescriptions more frequently than recommended by national guidelines. Only 36% of bronchodilator users reported ever having been told to keep track of pMDI doses used. Of those, 79% had been advised to do so by a physician, 6% by a pharmacist, and 3% by a nurse. Eighty-seven (25%) of the 342 respondents who named a bronchodilator reported having found their pMDI empty during an asthma exacerbation. Seven of those patients had to call 911. Of these 87 patients, 71 (82%) considered their pMDI empty when absolutely nothing came out.


CONCLUSIONS
Patients do not have a reliable means of monitoring the contents of their metered-dose inhalers, which is causing serious problems that need to be addressed. Given the necessity of a reliable dose counting method, it is clear that manufacturers should include dose counters as a standard feature of every metered-dose inhaler.
Sander
Nancy
N
Allergy & Asthma Network Mothers of Asthmatics, Fairfax, Virginia, USA.
Fusco-Walkert
Sandra J
SJ
Harder
Julia M
JM
Chipps
Bradley E
BE
D000293:Adolescent; D000305:Adrenal Cortex Hormones / Q000008:administration & dosage; D000328:Adult; D018927:Anti-Asthmatic Agents / Q000008:administration & dosage*; D001249:Asthma / Q000188:drug therapy*; D001993:Bronchodilator Agents / Q000008:administration & dosage; D002648:Child; D002675:Child, Preschool; D003625:Data Collection; D004349:Drug Packaging; D004630:Emergencies; D004867:Equipment Design / Q000592:standards; D004868:Equipment Failure / Q000706:statistics & numerical data; D004869:Equipment Safety / Q000592:standards; D005260:Female; D007722:Health Knowledge, Attitudes, Practice; D006801:Humans; D008297:Male; D036501:Metered Dose Inhalers; D008875:Middle Aged; D010353:Patient Education as Topic / Q000706:statistics & numerical data; D017410:Practice Guidelines as Topic; D011312:Pressure; D012494:Sampling Studies; D012646:Self Administration; D011795:Surveys and Questionnaires; D013997:Time Factors
D000305:Adrenal Cortex Hormones; D018927:Anti-Asthmatic Agents; D001993:Bronchodilator Agents