FDA Approved Inhalers
Inhalers that are approved for use by the Food and Drug Administration (FDA) in the United States can be classified into two categories: metered dose inhalers (MDIs) and dry powder inhalers. Metered dose inhalers are usually used as asthma rescue inhalers or reliever medicines. There are breath-actuated autohalers such as pirbuterol acetate (ex. Maxair Autohaler), which releases the medication when you breathe in which is convenient because one does not need to coordinate actuation with inspiration, and there are non breath-actuated pressurized inhalers such as albuterol sulfate (ex. ProAir-HFA) in which the medication is released by pushing the canister down into the holder. HFA stands for hydrofluoroalkane and because the FDA has banned the use of chlorofluorocarbon (CFC) based propellants, companies have stopped using CFCs and started using HFA based propellants instead. As of 2012, the following inhalers have been phased out because of this FDA ban on the use of CFCs: Tilade Inhaler (nedocromil), Alupent Inhalation Aerosol (metaproterenol), Azmacort Inhalation Aerosol (triamcinolone), Intal Inhaler (cromolyn), and Aerobid Inhaler System (flunisolide).
Metered dose inhalers contain different types of medication. There are short acting beta agonist inhalers such as ProAir, Maxair, and Xopenex. These inhalers are used as rescue inhalers and they provide quick relief by opening the airways. Xopenex contains the active form of albuterol with less of the effects of albuterol inhalers because it tends to cause less jitteriness (a common albuterol side effect) in patients than albuterol sulfate inhalers. They are best used for treating sudden asthma attacks but they can also be used before exercise for those who suffer from exercise-induced asthma.
There are also long acting beta agonist inhalers (LABA) such as Serevent and Foradil and these inhalers provide asthma control and should never be used as a rescue inhaler. They can be used with inhaled corticosteroids (ICS) such as Azmacort, Pulmicort, and Qvar for long-term control of asthma symptoms. There are also inhalers such as Advair HFA and Symbicort that are a combination of LABA and ICS and are used for patients with more chronic asthma that is not controlled with other medications. Other drugs like ipratropium (Combivent, Atrovent) etc are also available in MDI forms. All of these inhalers are bronchodilators.
Some of the above-mentioned inhalers also come as dry powder inhalers (DPIs). These are a group of inhalers that have the medication in very fine dry powder format. They are classified into single dose devices, multiple unit dose devices and multi dose devices. Single dose devices such as a Handihaler, Rotahaler, Aerolizer etc. require the patient to insert a dose of medication into the device before inhaling. For example Spiriva Handihaler, though commonly used as a chronic obstructive pulmonary disease (COPD) inhaler it is also occasionally used for asthma treatment and it involves inserting a capsule into the device, pressing a button on the device that pierces the capsule, then breathing in the powder contained in the capsule through the mouthpiece.
Multiple unit dose devices contain multi dose blister packs coiled inside the inhaler that are to be punctured before inhalation. An example of this is Relenza Diskhaler which is used for allergic rhinitis. Multidose devices such as a Diskus (ex. Advair Diskus), Twisthaler (ex. Asmanex), and Flexhaler (ex. Pulmicort) contain all the doses in a reservoir and it is delivered after proper inhalation.
More recently, it has become easier to buy inhalers because of the introduction of over the counter (OTC) inhalers. Primatene mist inhalers (epinephrine inhalers) were sold as OTC inhalers but because they use chlorofluorocarbons (CFCs), which are harmful to the ozone layer and are no longer approved by the FDA, they have been taken off the shelves.