How frustrating! I just did some searching on google to see if there were alternatives to antivert, but it looks like they are all antihistamines with the side effects you have.

I hope you can find out what is causing your vertigo, so you won't have to take it any longer. {{{hugs}}}

I looked it up too, and it says it's for motion sickness, but you only mention having osteoarthritis. It doesn't mention any off label uses for pain. Why are you on this medication? If you need it for motion sickness or nausea, and it's causing you this much grief, can you talk to your doctor about an alternative, or possibly use and alternative OTC med? I know drugs for nausea typically make you sleepy, so it seems like they would have recommended you take it before bed.
Seems like you need to take something for the arthritis pain. I was in love with Vioxx for that, but someone had to go and have a heart attack or something and it was yanked off the market. Celebrex is decent, and Cymbalta actually worked well if you can deal with those side effects. Other than that, you have regular NSAIDs like Mobic or Naprosin. None of those cause drowsiness, although prolonged use is not good for you.

The antivert is for a separate problem which is vertigo likely due to an inner ear issue. The side effects are awful, but it's a lot better than the room spinning. Just wish there was something that didn't cause drowsiness. I've been taking Ibuprofen 600mg for the pain, which works most of the time but sometimes the pain is too much for even that to block it. They actually prescribed me Percoset, but there is no way in hell I am ever going to take a narcotic unless I am literally rolling on the ground in pain.