Hi,
Re the anti-emetics:
I reckon the CRPS pain can cause nausea but the other meds we use can too. Opioids have a reputation for this but this is dependent on type of opioid and dose and if your dose has been titrated upwards slowly.

I use prochloperazine (Stemetil in Australia) either as a tab or orally but this can cause spasticity (like Monty Pythons' department of silly walks but less extreme) if you take a tab / suppository and then have to get an injection. Make sure you tell your doc. I have no side effects.

I also take Maxalon as it is known in Australia (Metoclopramide HCl) orally. No ill effects. Generally 10 mg works well if you aren't @ the vomiting stage (obviously).

Good luck. Hope this helps.
Auberon.