2013年9月28日星期六

Asthma inhalers



The New York Times has an excellent piece today on the phasing out of old asthma inhalers, which has already begun. However, the old asthma inhalers will completely unavailable by the end of the year. Many asthma inhalers are pressurized metered dose inhalers (pMDI’s) which means that when you push down on them, the medication sprays out like an aersol spray. Not all inhalers are pMDI’s. Some of the newer inhalers are dry powder inhalers (DPI’s) where the medicine is not sprayed out, but simply inhaled (Advair and Pulmicort are both DPI’s). However, all the rescue medication products available in the US (which is almost always albuterol) are only available in pMDI’s. The problem is that the propellant in these sprays was a CFC, which is bad for the enviornment. CFC’s have been banned by the government, and the asthma inhalers are the last remaining consumer products to have them. The new pMDI’s are made with another propellant, that is more environmentally friendly, HFA. However, there are several differences between the CFC pMDI’s and the HFA pMDI’s.


There is no generic albuterol HFA
The FDA considers the HFA inhalers new drugs, even though the active ingredient is off patent.
Issue #1- if the physician just writes albuterol, the pharmacist will likely dispense the CFC pMDI which will not be available in January 2009, and more importantly may not be available now because supplies are limited
Issue #2- if the physician writes albuterol HFA, since this product does not exist, the pharmacist will likely substitute one of the 3 branded products (ProAir, Ventolin HFA, and Proventil HFA). However, it may matter to you which one of these you get because………
Issue #3- each insurance company has a different policy regarding the CFC to HFA transition. The HFA inhalers are much more expensive. On the other hand, insurers worry that increasing the cost of the co-pay may decrease the use by patients and land them in the Emergency Room. Some insurers have picked one of the 3 products and assigned it a generic co-pay while others have no preference and assign all products the same higher co-pay.


There are some differences between the old CFC inhalers and the new HFA inhalers
The spray from the HFA inhalers is weaker. Inhalers require more priming (wasting the first few pumps) before the first use. Patients may feel a difference in the force and taste of the spray ( and confuse this for the medication not working). The HFA inhalers also require a slower and deeper inhalation.


There are some differences between the new inhalers
ProAir, Ventolin HFA, and Proventil HFA are all albuterol products. Ventolin HFA (made by GSK) has one advantage in that it has a dose counter. Research has shown that many asthmatic patients incorrectly estimate how much medication is left in their inhaler. Most inhalers will continue to spray propellant even when the active ingredient has been used up.
Finally, there is a 4th product called Xopenex, which is levalbuterol. The medication is very similar, but because of its structure may have fewer side effects such as shaking or rapid heart beat. Though the branded Xopenex HFA is currently more expensive than the generic albuterol CFC, when compared to the other three albuterol HFA’s, Xopenex may be the same or even less of a co-pay then the others, depending on your insurance.


What you should do
1. If you have asthma, disccus the CFC to HFA conversion with your doctor to make sure you are getting the right medication.


2. Know the co-pay level that your insurance will charge you for ProAir, Ventolin HFA, Proventil HFA and Xopenex HFA. If any of these are a generic co-pay, switch now. All things being equal, Ventolin (dose counter) and Xopenex (fewer side effects) may be preferred.


3. Use these medications for rescue only. The medications are really only for bad symptoms and emergencies. Current guidelines state that if you are using these medications more that two times a week, your asthma is not well controlled, and you need a better maintenance inhaler, which is an inhaler you take every day to control your asthma.


4. Recognize the differences between the HFA and CFC inhalers. As above, the spray will feel different, and will require some adjustments (priming, slower inhalations) than your previous albuterol pMDI.


5. Do not use Primatene Mist to save a few bucks. This is an over the counter asthma inhaler. It is dangerous and would never be approved by the FDA today. Older medications that are currently over the counter need to have been proven to kill or severely injure people before they will be pulled from the market. This is hard for Primatene Mist, because hard to say whether or not it was the inhaler or the asthma. The active ingredient is epinephrine which has a lot of side effects.


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