Patients taking the new anticlotting drug Pradaxa may be in for a surprise. The capsules deteriorate quickly when exposed to humidity, and come with just a 30-day expiration date. Even some pharmacists appear not to be aware of this, and we are already hearing of patients having to throw away this expensive new medication.
Pradaxa (dabigatran) is designed to help prevent stroke in people with atrial fibrillation, causing the heart’s upper pumping chambers to beat in helter-skelter fashion. According to FDA, more than 2 million patients have atrial fibrillation. This puts these patients at risk of developing blood clots that could travel to the brain and cut off oxygen.
Until now, most patients have been treated with the anticlotting drug (“blood thinner”) warfarin (Coumadin). With warfarin, it’s important to monitor patients with a blood test to assure not only effectiveness but also that the blood isn’t too “thin,” which could lead to bleeding.
Unlike warfarin, Pradaxa capsules are given in a fixed dose of 75 mg or 150 mg, morning and evening. There is no need to monitor blood tests to guide proper dosing and there aren’t any important interactions with food and only minimal drug interactions. This is not to say the drug is without any risk. There is still a potential side effect of life-threatening bleeding and other problems such as stomach discomfort and bloating.
But here's what patients need to know. A less than prominent statement in product labeling mentions that Pradaxa capsules expire just 30 days after the bottle is opened. Since each Pradaxa bottle contains 60 capsules, that’s a month’s supply. So prescriptions for more than a month's supply (e.g., 60- or 90-day supply, if allowed by your insurance provider) require that you open only one container at a time. When the supply of capsules from the first container is exhausted, the second container may be opened.
To complicate matters, the bottles are not sealed with a tamper evident seal, so patients may easily confuse an already opened bottle with one that is not yet opened. A pharmacist told me recently of one patient who began to take capsules from two different containers at a time, and therefore had to discard unused capsules from both bottles before the end of month. What a sin to waste a drug that costs about $200 - $300 a month.
When I spoke with several pharmacists as well as consumers taking Pradaxa, I found out that none of them were aware of this. Surprisingly, this information does not appear on the package label but instead is buried in the official package insert and a patient medication guide.
Later, I learned that some pharmacies appear to be responding by putting a label on Pradaxa that says it expires 30 days after opening.
One idea for patients who get more than a month’s supply is to ask pharmacists to provide Pradaxa in available unit dose blister packaging. These capsules have over a one-year expiration date as they remain unexposed to air until peeled open. If dispensing bottles, we have advised pharmacists to mark them as bottle #1, bottle #2, etc. to indicate which bottle is the one from which to remove capsules until that bottle is empty. The container should then be discarded and the second container started. Do not place the capsules in any sort of daily pill dispenser you might have.
Boehringer Ingelheim Pharmaceuticals Inc., the company that markets Pradaxa, should have anticipated these problems and designed more convenient preventive packaging to anticipate that the bottle won’t always be used as intended. For now, they need to at least place a much more noticeable message on the bottle or bottle cap itself to help make people aware that capsules should be discarded 30 days after opening the bottle.
For information on ISMP's consumer web site go www.consumermedsafety.org
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