Hi Cedar ~ you know me well enough to know I'm not educated or anything but it's my experience that we all have DIFFERENT tolerance levels for meds.
And - I can't remember what med it was but - I was doing quite well on a med but woke up one morning VERY dizzy and CROSS-EYED. I could not even see well enough to call for help ... I even tried to phone my husband's office and could not do it.
Long story ......
Much later I managed to phone my neuro and he said I was badly OD-ed on my prescribed dosage. According to his direction I cut my dosage by 1/3 and did just fine.

Anyhow - I am reasonably certain that "prescribed dosage" means nothing for EVERYBODY. Each of us is very different and reacts very differently to each drug. Right?

Best wishes.