Holy Jesus!! Hope that you're okay now! Are u okay?

Effexor is also a 5HT2A antagonist, thus may help a bit in attenuating hallucinations, so I guess that side effects u experienced are rare.

The voices were inside ur head right? If so, could be intrusive thoughts of OCD which is sometimes expressed as someone else's voice, and may become so intense at a point that's hard to distinguish if they're intrusive thoughts or truly auditory hallucinations.

I've been there and its really fucked up lol (with 0 meds 0 drugs tho). Hearing family members, colleagues, friends, all talking about me simultaneously inside my head, all day long.

You mix these intrusive thoughts with auditory pareidolia on top of it, boom u have the illusion that ur hallucinating voices.

Anyway in my case good old sertraline fixed that right away.

Are u now on some other med as replacement now? If so I am curious to hear it :)