This post is for information only.
Credit and enthusiasm for my "med maths" to Fishinghat
PLEASE NOTE - This is only a theoretical guide based on bioavailability statistics. Exact release of medication can vary depending on other factors (diet, body mass, cause of illness, personal circumstances etc). This is not to be used in place of professional advice for your own circumstances! Invalidusername takes no responsibility - and I'm sure Fishinghat would be the same
If you are coming off Duloxetine and starting Citalopram (or another), there is always the question of whether you take both at the same time, or stagger 12 hours apart. Put simply, by staggering you sacrifice the "high" in the middle of the day for a potential greater release in the morning (assuming you take the Citalopram - or longer release med - in the evening).
Clearly this may have issues if people suffer insomnia as a result of taking their SNRI/SSRI too close to sleep. However, I hope that this may help those who - like most - have their worst moments in the morning when waking, and usually feel better as the day goes on, and thus can afford a dip in maximum release at these times.
So the conclusion is... a 18% increase in bioavailability in the morning when staggering compared to taking together, but a 20% decrease at peak release. An additional benefit would be the reduced risk of serotonin syndrome, and an overall flatter (more consistent) release of bioavailability.
This comparison is based on DULOXETINE and CITALOPRAM. If you would like a comparison of another drug, please let me know.