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Dr. Bob is Robert Hsiung, MD,
bob@dr-bob.orgShown: posts 1 to 6 of 6. This is the beginning of the thread.
Posted by Wildflower on October 9, 2005, at 15:06:58
I'm really bad at half life math. Could someone please tell me if the following is true?
I'm on Cymbalta 60 and my pdoc has prescribed the following to lower the dose to 40. She has me take one 60 two days in a row and then take nothing on the third day.
Does this seem right to equal 40?
Posted by Racer on October 9, 2005, at 16:35:17
In reply to Cymbalta half-life math, posted by Wildflower on October 9, 2005, at 15:06:58
Doesn't sound right to me, but I'm not any kind of expert.
Cymbalta has a shortish half-life, as I recall, maybe around 12 hours or so? If that's true, than taking the next dose 24 hours later, you're already past the point when half the medication would be out of your system. Trying to equal 40mg by taking 60mg two days in a row and nothing the third just doesn't sound to me like the way to do it.
Again, that's just me, and I certainly don't know as much as others here, let alone your doctor. I look forward to reading something from someone with more knowledge of this area.
Posted by blueberry on October 10, 2005, at 6:01:07
In reply to Cymbalta half-life math, posted by Wildflower on October 9, 2005, at 15:06:58
The half life is about 12 hours, varying from 10 to 17 hours in different people.
A better way to go would be to take 20mg caps twice a day. More expensive too though.
A very tedious way to do it would be to empty a 60mg capsule onto a plate and separate out about 2/3 of the beads that are inside, which would be about 40mg. Getting them back in the capsule would be hard. Or you could sprinkle them onto pudding or something soft that doesn't require chewing (the beads are enteric coated, so you don't want to damage them or they'll be useless). It would be tedious, but it would work.
I wish the drug companies would make more dosage size choices, for better ease of getting on the med, easier weaning off of the med, and more customized dosing for each individual.
Posted by Glydin on October 10, 2005, at 20:27:19
In reply to Cymbalta half-life math, posted by Wildflower on October 9, 2005, at 15:06:58
Based on the total dose you would be getting over three days, that would kinda appear correct. 2 caps at 60 mgs. then no dose would give you a total of 120mgs. divided by 3 days would give you 40 per day. The math would seem right but I'm not sure in terms of absorption and elimination if that's how the body would "see" it.
But, if that's your doc's recommendation, trying it out and seeing how it goes is the way to find out.
Posted by Wildflower on October 11, 2005, at 13:21:37
In reply to Re: Cymbalta half-life math » Wildflower, posted by Glydin on October 10, 2005, at 20:27:19
Thanks for your post! I've been on this schedule for a while but I feel really off the days that I don't take the Cymbalta. It seems to throw my body out of whack. I have a doctor's appt. Friday. Maybe I can just take the 60 each day. There was an annoying SE of under arm sweating that I was tired of having. Hence the drop in dose...
Posted by Racer on October 12, 2005, at 13:45:44
In reply to Re: Cymbalta half-life math, posted by Wildflower on October 11, 2005, at 13:21:37
> Thanks for your post! I've been on this schedule for a while but I feel really off the days that I don't take the Cymbalta. It seems to throw my body out of whack.
That right there might be a hint that this isn't actually good math... (Sorry, that just struck me as funny, somehow, although I know it's not.) If you're experiencing a mini-crash on the third day, the day you don't take it, that shows that you're going into mini-withdrawal.
Since Cymbalta is available in 20mg capsules, why not just take two of those per day? (I'm moving from 60mg to 40mg myself next week, once I'm completely off Lamictal. I'm hoping that will continue the good effects of Cymbalta without so much sedation.)
Good luck at the doctor's.
This is the end of the thread.
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