Serious harms begin with the heart
Ibogaine has been associated with prolongation of the QT interval, a change in cardiac electrical timing that can increase the risk of dangerous ventricular arrhythmias. The clinical concern is especially acute where a person has underlying heart disease, a history of fainting or arrhythmia, low potassium or magnesium, or concurrent exposure to other QT-prolonging medicines. The long QT syndrome overview helps explain why altered cardiac repolarization can matter even when symptoms are not immediately obvious.
Reported harms also include slowed or irregular heart rhythm, loss of consciousness, seizures, aspiration, respiratory complications, and abrupt changes in blood pressure. These outcomes cannot be reduced to a single cause in every case: reported fatalities may involve pre-existing illness, withdrawal, other substances, medication interactions, uncertain product contents, or inadequate monitoring. That uncertainty does not make the safety signal less serious.
For wider context on the substance and its pharmacology, Rootwake’s ibogaine overview situates this risk discussion alongside cultural context, research, policy, and unanswered questions.