Drug info - E/MDMA Mixed with antihistamine drug to prevent vomiting/nausea

[Conkermon]

My quick-witted pet fox has come to the realisation that unless something is done to help his weak stomach he will be unable to continue taking E/MDMA or Ketamine for that matter.

He had previously turned to Ketamine to avoid the sickness that he finds so common with E/MDMA but now even K has begun to make him feel nauseous. The other foxes are getting tired of his company when drugs are involved as he always seems to feel unwell, leave early as a result and put a slight downer on the night. They think that my poor fox is to blame and it is because he thinks about things too much (which is true, but unrelated?) My fox is fairly sure that he just has a weak stomach, which would make sense since he has always eaten unadventurously and has avoided the ghastly fried chicken that the other foxes seem to love and can be procured from the dodgy take-aways on the streets of London.

Anyway, to get to the point:

My fox was wondering how safe it is to combine E/MDMA or Ketamine with these anti-histamine drugs such as dimenhydrinate (sp?) or similar. He has heard that they suppress the nerves (?) that would cause nausea and vomiting but has often read that it is dangerous to mix drugs with anti-depressants and was wondering if this was similar? He also used to think that when he vomited it was his body telling him that he was in danger from all the chemicals in his system and thus he needs to expel them - would getting rid of this warning be harmful? Furthermore, are these drugs available over the counter (UK) or should my fox schedule an appointment with the vet and tell him about his (unrelated to drug use) nausea and motion-sickness?

Thanks in advance, my fox eagerly awaits your advice.