so I have been reading a bit about ketamine infusions. I am not the best at finding info online...What I have found seems great. Patients get "significant reducation or elimination of pain for 6 months"... Is this true? If so, why doesn't everybody get ketamine infustions? what are the side effects? How long can you go on receiving these infusions? Does the effect wear off? (after 4 infusions it no longer works?). Is this a last resort? if so, why?
Sorry for all the questions, I just can't figure out why everybody doesn't get these instead of opiates etc.

Thanks!