Question: Are Metered Dose Inhalers Harmful to the Environment?
Answer: Because metered dose inhalers are an aerosol and contain propellants, people worry they will be harmful to the environment or ozone layer. While this may have been true in the past, it is becoming less true as each month passes.
At one time, all MDIs did contain substances called chlorofluorocarbons, or CFCs for short. These substances acted as propellants, which means they helped propel the medicine mist out of the canister and into your airways.
CFCs in other products, such as deodorant spray cans, have been found to deplete the ozone in the atmosphere, so they have been banned internationally. In fact, the production of ozone-depleting chlorofluorocarbons (CFCs) was discontinued on Jan. 1, 1996, for all uses deemed non-essential under the Montreal Protocol.
However, the use of CFCs as propellants in MDIs was classed as essential, providing an exemption from the agreement. While the U.S. agreed to go along with the worldwide ban on CFCs, they were still allowed to be used in medical devices, such as MDIs, until a replacement could be found.
Following extensive research, the hydrofluoroalkanes (HFA) 134a and 227 were identified as the only suitable replacements for CFC propellants in MDIs. So, we are currently in the process of phasing out CFC inhalers in favor of the more environmentally-friendly HFA-type inhalers, a transition that should be complete by the end of 2008.
For more information on what to expect from this new type of inhaler, see Switching From CFC to HFA Inhalers
Sources: FDA Proposing Phase Out of CFCs in Metered-Dose Inhalers for Epinephrine. U.S. Food and Drug Administration; 23 January 08. http://www.fda.gov/bbs/topics/NEWS/2007/NEW01706.html Topic of the Month - May - Transition to HFA Inhalers. American Academy of Allergy Asthma and Immunology; 23 January 2008. http://www.aaaai.org/patients/topicofthemonth/0507/
