Canada. Health Canada has received 16 cardiovascular ADR reports associated with synephrine- or Citrus aurantium (bitter orange)-containing products between 1 January 1998 and 28 February 2004. All cardiovascular adverse drug reactions (ADRs), including cardiac arrest, ventricular fibrillation, tachycardia, transient collapse and blackout, were considered to be serious, and two cases were fatal. In 15 of the 16 cases, the suspect products also contained either caffeine (n = 7) or caffeine with ephedra or ephedrine (8).

Reference:

Canadian Adverse Reaction Newsletter 14, No.4, October 2004.