At what dosage does effexor (venlafaxine) xr become cardiotoxic? studies sayfor overdose 1000mg but what about 225mg-450mg that some folks take? is that high enough

It's pretty safe.: They don't actually do controlled trials of overdoses in humans. Therefore the experience is based only on those who try suicide and they are not a reliable group. http://www.accessdata.fda.gov/drugsatfda_docs/label/2005/020699s059lbl.pdf 2.75 GRAM was slightly cardiotoxic, BUT 1) other drugs potentially interact 2) underlying heart disease will interact with it.