I wish I had more time to get stuck into a better reply.
We all know that with Iboga there is a potential interaction that it could block potassium channels on the heart cause prolong QT intervals and cause potentially dangerous arrhythmias, which is why this drug should really be used with caution.
Now don't get me wrong but I don't like the idea of a big pharma kind of situation controlling any 'safe' psychedelic drug but this is one drug i feel should be restricted to a skilled/ qualified clinical setting (even if it was to say be an independent clinic). In-case of worst case.
Having said that, for someone who has been working in the 'Iboga field' for two years it doesn't fill me with confidence that you are a skilled clinician that could help a patient if something was to wrong, as you are asking the internet for answers to questions someone in the 'field of iboga'(?) should know. Addicts aren't exact known for there good health and lifestyle choices many addictive drugs are linked to cardiac issues. Which is why i feel with something like Iboga and addicts it is so important to be doing in a clinical setting for medically trained professionals. These are peoples lives you could be putting at risk. (Yes I understand the irony there).
As for countering potential cardiac issues with magnesium, calcium, vitamin B, hERG channel activators are what you'd want to use and they are not that well studied in humans and many compounds like matrine and carbachol come with a whole another set of interactions, issues and dangerous side effects.
Maybe leave Iboga for properly equipped clinics/ clinicians.
Disclaimer: All my posts are of total fiction.