Question about generic drug...

[pem]

A couple things -- thanks for the kind words, I'm working through the (fortunately minor) issue of a slight limp and hope to resolve it soon.

I strongly believe in weekly testing. The few times I didn't test that often during the past year or two, my 'late' test was often a surprise. I can't quite understand the belief that, if your INR is the same with a blood draw every month, your INR will be stable all the time between tests. With strips costing just a few dollars each (possibly less than driving to a lab and paying for parking), the idea of self-testing can be compelling to many people. For me, financially, it was the only choice.

When I first switched to generic, I carefully tested to see if there were any changes in INR. I don't recall any. When changing from one manufacturer's warfarin to that from another manufacturer, it's not a bad idea to waste a few strips and just be sure of the effectiveness of the new brand.

They've been using these generics in other countries around the world, and keeping people properly medicated. I don't remember hearing any horror stories about warfarin in other countries causing injury.

Like Reagan once said 'Trust, but verify,' this may be the same approach to take when switching to warfarin from a new manufacturer.

Just curious - what do you (or anyone else reading this) think is the best algorithm for adjusting coumadin dosage? I've seen a few online, some more easy to interpret than others, but most apply to the 2.0-3.0 range. Is there a single sanctioned method for this? In general, the guidance I've received from INR nurses tends to vary and not follow the specific flowcharts I've seen.

Thanks,
pem

 

[RobThatsMe]

I was on the name brand Coumadin for the 10 years following my first VR surgery.
My doctors always would tell me that VR patients should only take the name brand.
So, I stayed with it. Even though my Presciption Medicine Insurance hit me pretty good with fees because I would not use the generic. The cost was indeed expensive.

Then, after my most recent VR surgery, I was given the generic brand, warfarin, while recovering in the hospital at the Cleveland Clinic.
So, for the last 18 months I have continued to use the generic brand with NO issues. I home test every other week, and sometimes weekly. It sure has saved me money, and as mentioned, my INR monitoring is stable.

Rob

 

[dick0236]

Just curious - what do you (or anyone else reading this) think is the best algorithm for adjusting coumadin dosage? I've seen a few online, some more easy to interpret than others, but most apply to the 2.0-3.0 range. Is there a single sanctioned method for this? In general, the guidance I've received from INR nurses tends to vary and not follow the specific flowcharts I've seen.

pem

There are a number of methods on the internet. My system is pretty simple. Normally I take 5mg/day. If I am only a tenth or two above or below my norm(2.5-3.5), I do nothing, other than adjust my diet a little, and test in a month. If I am .3 or so above, I reduce by one l/2 dose(2.5mg) and test in a month. Above 4.0, I normally reduce by one 5mg dose and test in a week. On the bottom end I do about the same, althogh I am apt to add a full 5mg dose if I get close to 2.0. I like to work in 2.5mg adjustments since it can be done with only one strengh Rx(5mg) Very seldom, anymore, do I have to add or subract dosing because I can normally stay in range thru diet/activity. adjustment. Understand that I have been on this stuff for a long time and am very comfortable with it. Until you become comfotable, stay on the consertive side and listen to a good doc or INR nurse.....and don't be afraid to question their dosing instructions.

 

[Protimenow]

Dick: I don't quite understand your formula -- are you saying that, if you're a tenth above, you reduce your 5 mg dose to 2.5 mg for ONE DAY and test a month later? Or are you saying that you drop it in half EVERY DAY and test in a month? I suspect that you're dropping the dose one time during that entire month. If so, and your next blood draw is three weeks later, the effect of what you do today won't show up on your monthly test.

I haven't been on warfarin nearly as long as you have, but I'm most comfortable testing weekly -- even though, if I test on a Sunday, any changes on Monday will NOT show up on the following Sunday.

When we're testing, we should take into account the amount of time it takes for a dose today to show up in our INR, and then to taper off. A test done too long after a change in dose will NOT show up.

I don't mean to get fanatical about testing frequencies, but I know, from personal experience, that more frequent testing can help you keep in range more often -- and that stretching out the intervals between tests only tells you what your INR is at the jmoment of testing - with no clue what it may have been between tests. It's nice to believe that our INR is stable - and, perhaps, for some people who have the same diet and activity all the time, this may be so, but I'm not sure I'm willing to bet my life on it.

---

As far as dosing algorithms, I usually use a pretty basic formula -- if my INR is slightly below range, I increase my total weekly dose by 10%, if slightly above, I reduce it by 10%. Adding greens to the diet can also help to drop a too high INR. In the rare cases where an INR drops below 2.0, I use the Duke Clinic algorithm (you can look it up, I don't have the link handy) to increase your daily dose by 50% the first day (I'll have to see what they suggest on the other days).

I'm sorry if I sound a bit preachy -- but it's our lives that we're playing with, and I think that in this case a bit more knowledge can be a good thing as long as you don't spin off into messing with your dose every time you get a result that is slightly above or below range -- too much tweaking can restart the INR roller coaster.

 

[dick0236]

Dick: I don't quite understand your formula -- are you saying that, if you're a tenth above, you reduce your 5 mg dose to 2.5 mg for ONE DAY and test a month later? Or are you saying that you drop it in half EVERY DAY and test in a month? I suspect that you're dropping the dose one time during that entire month. If so, and your next blood draw is three weeks later, the effect of what you do today won't show up on your monthly test.

too much tweaking can restart the INR roller coaster.

Sorry I didn't make myself clear. I seldom make more than a one day change. If I am a little out of range(.1 or .2), I make no change. If I am more than a little out of range(.3 or .4), I make a one time l/2 dose(2.5mg) change. In either case I normally do not retest earlier than my norma one month. If I am moderatly out of range(.5+), I make a one time one dose(5mg) change and retest in one week. I have home tested on a weekly basis and doc office tested both bi-weekly and monthly. Currently I doc office "finger stick" test monthly. I understand that "new standard" is weekly, but I consider that "overkill", especally if you have a stable INR history. FWIW, I went to my computer INR log and found that I have made two(2) one time, l/2 dose(2.5mg) reductions since Oct., 2008......and it has been a number of years since I've taken an increased dose(thankfully). As I have, or should have, posted, I've done this a long time and do not necessarily suggest that people new to warfarin follow my routine. However, I also don't believe that people should be overly frightened of warfarin. The drug is not out to ambush you.

 

[RobThatsMe]

My 2 cents... I do not try to get a formula to compare my home testing results to the lab results.

I go to the lab twice a year and compare my unit results to the lab results. As long as they are within a 0.3 range. I am happy.
This is how I have been doing this for almost 12 years. I want my range to be within 2.5 to 3.5, and really if it's between 2.0 and 4.0 then I am a happy camper, and will make slight adjustments to bring me back into range if I am just outside of it. I do not think that people with a range of 2.0 to 3.0 and home test are really within "MY OWN" comfort zone. I would bump it up to 2.5 as a min. This is to accomadate the safety factor to be within the tolerence between home units versus lab testing.

You need to place your confidence in one choice. That being said, make sure your choice stays within tolerence.

Coumadin has really been a non-issue with me for 12 years.

Rob

 

[Protimenow]

Dick - I agree, Warfarin is probably way too scary for a lot of people.

I've told many people that INR is manageable and not to be feared.

However - you and I both have something in common - a history of stroke as a result of being under anticoagulated. In my case, I think my old meter was overstating my actual INR and I may have gone for a few WEEKS with an INR that was under 2.0. I was also testing every two weeks because I was trying to not run out of strips. If this was a consistent error by the meter, then testing more often shouldn't have changed the course of my issue. I'll compare tests made with the new meter that I expect to get tomorrow to the old (five YEARS old) meter that may have given me the erroneous results.

However, as you said, warfarin is NOT to be feared.

 

[tom in MO]

Dick, I've only been on warfarin for 9 weeks, but my clinic has the same exact approach as you.

Per testing fequency, due to the nature of warfarin, what I've read and what my clinic says is that once per week is all that is needed once you establish a blood level. Any change in dose will not be fully realized within just a couple of days, that's why they wait a week to see a more stable level.

Many people were scared off generic drugs due to the scandals of a few years ago. FDA reviewers were caught taking bribes to accept data for generic drug applications that was really generated with the name brand; outright fraud. There was a lot of change in the generic drug industry and FDA after that, so past practices should be gone, particularly with a high visibility drug like warfarin.

 

[Bill B]

I missed this thread earlier. My basic conclusion as a pharmacist who looked at this issue a while back is that the approved generics in the US are equivalent and there is no reason to expect different results from Coumadin or any of the other approved generics. Yes, there have been some "case reports" of changes in INR when changing brands, and many reputable facilities recommend checking INR carefully if someone is being changed to another brand, but my belief is that these cases were not well documented and are coincidental. INRs can fluctuate for a lot of reasons, and based on what I know about the approved products, it's not a brand issue. I personally do not have a concern with the approved products, but I don't fault people for being more cautious about this than I am. As was said, this is scary stuff for many people and appropriately so. This is a critical drug with dangerous potential if misused and sometimes even when used in accord with best practices. So, I get the concern. And me trying to tell people it just doesn't matter which one you use is not always the best answer. Maybe technically correct, but not acceptable, under the circumstances.