Hey
@amandine ...glad you found something in that mish-mash. I had to come back online to finish up some more with PM's so figured I had better throw in the last few cents now before 2 pages more appear tomorrow morning!
Yes, the "side effects" of any drug really are generally speaking where the active agents in the drug hit more areas than just the "specific target". Obviously if the drug just hits the one area we want, then "Bingo!" As you know, the side effect profiles of most drugs read like a shopping list from hell, so one takes ones chances and hopes for the best.
With Retigabine hitting so many of the Kv7's (Gene ref. KCNQ) = Kv7.2 to Kv7.5, there is a wider spectrum for "expression" than say just having a Kv7.3 drug.
So the deal is, that genetic expression of these KCNQ's are in numerous places in the body and thus when taking the drug these places can be affected, depending on the individual, etc., etc. Primarily for instance. Kv.7.2, Kv7.3. and Kv7.5 work in the brain and ganglia, and "excitation" aspects thereof...(though not so sure on Kv7.5 and the particular epilepsy excitation connection). Anyway, that makes sense for epilepsy as it can be brain-wide condition for all appearances. Not that I'm a neurologist but have seen a few folks have grand mal seizures in my day and it sure looks brain-wide!
OK, apart from the brain (and cochlea and vestibular hair cells for Kv7.4) there are other KCNQ's in the urinary tract, kidneys, heart, etc. and obviously some connection to pigmentation in the retina, lips, nails, etc. - but God knows on that score what's really happening.
Hopefully a more targeted Kv drug will just go for the more "tinnitusy" stuff and leave peeing and so forth alone.
Best, and thanks for asking how I'm doing. Not as good as was on Potiga...though can do without the H that tagged along when on it... Zimichael