Friday, February 11, 2011

Pradaxa's Not-So-Long Shelf Life

Dr. John Mandrola, a fellow blogging electrophysiologist, keeps us up to date regarding the shelf life issues of dabigatran (Pradaxa®):
Once dispensed, most medicines expire after a year. Dabigatran, however, is far from the usual pill. It’s packaged in pellet form within a capsule. These pellets are highly susceptible to water and humidity. So when dispensed in a typical vial–not a single-sealed blister pack–the drug expires in only 30 days.
I learned today from our pharmacy personnel that you can specify blister packs on a prescription which will assure a longer shelf-life of the medication (just be sure your patients can open them).

-Wes

5 comments:

Dennis said...

What a rip off (the vial form)... its almost like watering down insulin. Who would have known?

Nana Jackie said...

Pradaxa must be dispensed in the original bottle as it comes from the manufacturer. It cannot be dispensed in a standard prescription vial. Even with the special moisture-controlling cap on the original bottle, it has a 30 day expiry after it's opened. Much less wasteful to use the blister packed product. Aggrenox, another Boehringer Ingelheim product, comes packaged in the same type of bottle as Pradaxa and also has a very shortened shelf life once opened.

John Mandrola said...

Thanks for the mention.

Yesterday, an office staff person asked me an interesting question about Pradaxa. "How will you know whether the patient is actually taking the drug...With warfarin, it's easy."

Obviously, doctors will not know, they will trust that their patients did.

That's interesting an interesting point when it comes to cardioversion, or ablation of long-lasting AF. It used to be, if you cardioverted a patient with an unsuitable INR, and they had a stroke, that was trouble for you.

The angle I'm seeing is the whole patient responsibility thing.

M. Dean Keller said...

Hello Dr. Wes,
My name is MD Keller-(Dean) and although I am not a doctor, I do have an MS in engineering. I follow my medical treatment carefully since I have had Hairy cell Leukemia since 1965 and try to analyze everything. On Pradaxa's early demise, I would like to know if the short life after opening the bottle is a linear decrease per day in the efficiency of the medication or a decrease which is non-linear which would account for a rapid decrease after 30 days. The 'drop dead' command at the end of 30 days is simple minded. Thank you to anyone who could have this information.

DrWes said...

Mr. Keller -

It appears the drug is susceptible to moisture in the air - the more exposure to moisture, the more dabigatran's effectiveness wanes. After 30 days of time exposed to air, even when stored in the special bottle with moisture-absorbant material in the cap, the drug company cannot assure the effectiveness of the medication at thinning the blood adequately.

(At least this is my non-pharmachologic understanding of the situation - hope it helps).

Because blister-packed tablets aren't exposed to moisture in the same way, their shelf-life is considerably longer.