RCs Sertraline -- Accumulative Doses

[Michael_25]

The half-life of sertraline is 24 hours. I have been taking it for 6 days, 50 mg a day. In total, that's 300 mg. How does the half-life work for accumulative doses? If I were to stop taking it for 72 hours, how much remaining sertraline would there be in my system?

 

[Hodor]

Assuming you take the drug every 24 hours on average:

T+0 hours, immediately after first ingestion: You have 50 mg of sertraline in your system
T+24 hours: Half the drug has been metabolized, you still have 25 mg in your system. You take another 50 mg. This brings the amount in your system to 75 mg.
T+48 hours: Half of the 75 mg will have been metabolized, bringing the amount in your system to 37.5 mg, to which you add 50 mg, making it 87.5 mg.
T+72 hours: Half of those 87.5 mg will have been metabolized, you are now at 48.75 mg. Add another 50 mg, and you are at 98.75 mg.
T+96 hours: Half the 98.75 mg have been metabolized, you are now at 49.375 mg. Add another 50 mg, you are at 99.375 mg.

Basically, the maximum amount of sertraline in your system approaches a limit of 100 mg.

If you stop taking the drug for 72h, i.e. 3 half-lives, the amount left in your system will be 50 mg after 24 h, 25 mg after 48 h and 12.5 mg after 72 h.

 

[Michael_25]

Thank you, Hodor!

 

[ChemicallyEnhanced]

What about taking different amounts?
I'm prescribed 150mg/day and I always take *at least* that, but I sometimes take up to 350mg/day.
Does that mean the amount in my system will be in a state of constant fluctuation?

 

[d1nach]

Why are you taking it like that? I thought ssris work by long term changes not acute effects like say amphetamine.