20mg and 10mg on alternate days

[SurfingWaves]

I would like to build up to 20mg dosage by taking 10mg one day and 20mg the next and repeat that for a couple weeks. I read somewhere that people do this and the result is like 15mg in your system. Has anyone else done something similar? Thanks

[MyNameIsTerry]

This is the standard pharacokinetic model for meds when starting them.

The plasma levels issue is in relation to "steady-state" which is 4-5 half lives of any drug. It looks like this:

HL.......%
1........50
2........75
3........87.5
4........93.75
5........96.875
6........98.4735
7........99.25

If you alternate, you won't be trying to reach that and your blood plasma won't be trying to reach steady-state until you decide to stay on 20mg. I know they do this with long half life meds when coming off them e.g. fluoxetine but if a short half life med you would with eliminating a lot of the med from your blood plasma quite quickly hence withdrawal effects are more quickly seen. Citalopram isn't really short though.

I really don't know how it would feel but I know it wouldn't be aimed towards establishing a constant 20mg as the model above applies.

The model below shows clear elimination:

HL.......%
0.........100
1.........50
2.........25
3.........12.50
4.........6.25
5.........3.13

When its under 5% its no longer clinically significant. It's more complicated than this when you consider how people taper as it will mean some overlap and then with some meds (e.g. Benzo's) you also have the storage outside of blood plasma which also needs elimination.

Factors involved in speed of distribution (drug starting to work) & elimination (clearance out of blood plasma) can be things like age (children differ, there are specific calculations for age that can be used for older people), speed of metabolism, weight (which will impact on metabolism), renal insufficiency conditions, etc. There are some very complicated guides on the internet for those interested such as some books on pharmacokinetics on Google Books but they are very difficult to understand without a medical background.

So, if you do this alternating routine you will still be eliminating at the same time from the 10mg which you will be at steady state with. Steady state just means as much going in as coming out. Your additional 10mg will be on top of this and will still be eliminated per the above model but because it hasn't reached steady state, you won't be getting the full benefits of 20mg.

Another option would be to taper up by breaking a 10mg tab in half and taking 15mg per day to reach steady-state, see how you feel and then go up to 20mg. 20mg seems to be when people feel it a fair bit more so it might be wise to go even longer than the 5 half lives just to be sure you have got past any side effects.

Citalopram half life is 36 hours. So, to get to 5 of those it would be 180 hours or 7.5 days.

Some meds reach steady state quicker and it often states this on the professionals section of your med on Drugs.com e.g. Ven gets to that in 3 days.

[SurfingWaves]

Thanks for all the info Terry it is very helpful. It definitely makes more sense to split a tablet and take 15mg, I did notice the side effects a lot more when I jumped up to 20mg. It messed with my sleep a little and a new side effect that I have only experienced with previous withdrawals from other meds: if I turn too quickly it feels like my balance goes off for about a second and i get a dizzy head for a second which was a bit alarming, I hope this side effect goes quickly, I'm going to write a new thread about this side effect.

Thanks again for your kind help