Re: Swapping Ven to Fluoxetine
Originally Posted by
Munchlet
I took my last Ven tablet 37.5mg on Tuesday evening. Wed took a Fluoxetine instead and work up middle of the night with a banging headache so I took paracetamol and went back to sleep.
Wednesday was ok, few brain zaps, some loose Bowel movements and a bit of nausea but manageable.
Thursday again brain zaps, bit of nausea loose BM but head ok
Friday - worst day so far, nausea, really bad brain zaps, sinus type head pressure, complete melt-down in work which resulted in my crying for the best part of an hour. Took 2 paracetamol and it passed after a few hours.
Today- few brain zaps little bit of nausea this morning and slightly loose BM but better than the last few days, not feeling emotional at all and actually feeling ok.
While switching to fluoxetine is the best option for weaning off venlafaxine there is one problem with it which can make life a little difficult at the beginning. Venlafaxine has a very short half-life, about 5 hours for the immediate release, 15 h for XL, whereas fluoxetine's is about 6 days (and 16 days for its active metabolite norfluoxetine which does most of the work). That long half-life usually makes tapering off relatively symptom free as it takes about a month for all the fluoxetine to be metabolised out of the system, and around 80 days for the metabolite. However, this is it also means it takes quite a while for fluoxetine levels to build up in plasma so there is a significant period with not enough med in the system to maintain the neurogenesis mediated therapeutic response. Cross-tapering would help, but it needs guidance for a doctor who knows what they're doing and most GP don't - definitely do not try this without medical supervision. Getting the venlafaxine-fluoxetine dose equivalence right can also be tricky.
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The opinions expressed above are based on my observations and, where applicable, interpretation of cited data and are general in nature. Consult your physician before acting on anything stated.