Originally Posted by
MyNameIsTerry
It's got a half life of 10-50 hours. That's the time it takes to be reduced by 50%. Within this time there will also be a distribution time as well, the time it takes for the drug to reach it's peak in your blood plasma.
So, if you take 2 doses together, they will distribute and eliminate along the same timescales because it is not dose-dependant. For example, if you take 20mg at the same time, you will get 20mg which will decrease to 10mg over that 10-50 hours. If you stagger you dose by taking 10mg AM and 10mg PM, you won't ever get 20mg all in one go unless you overlap the doses so that they both combine in their peak plasma distribution phases. (which would be unlikely since this is normally a matter of hours, nowhere near the half life minimums). Finding the peak plasma times seems complicated according to Drugs.com's professional section, with it being a TCA, so that might explain why I can't see one when I normally do for SSRI/SNRI's on the same sites.
That's a pretty wide half life for a drug, especially with such a low minimum. It seems to be affected by certain liver enzymes and patients are categorised into 4 groups. One of them covers 77-92% of people, known as "extensive metabolisers", are those seen to have a normal metabolism for the drug. This will mean they will be someone inside that half life range, usually at a Mean average point.
---------- Post added at 07:19 ---------- Previous post was at 07:04 ----------
Unfortunately, that won't be the case since the drug will reach peak plasma concentration within so many hours but also be getting eliminated so that at it's half life, 50% has been lost. Adding another dose on top won't slow that down, it's not connected to the drug, it's based on your renal ability for the normal elimination of toxins. Given the long half, it would be a problem if not.
It will overlap the doses though which will cause a full 100% of one dose to be added onto whatever % is left of the other. Is that what you meant? Similar thing I guess, just not the full 20mg but if the GP is aiming for somewhere inbetween, it will do the trick.