Letters Section Editor: Stephen J. Lurie,
MD, PhD, Senior Editor.
To the Editor: Dr McBride and colleagues1 suggested that ephedra might be responsible for
prolongation of the QT interval, increased P-wave duration, and elevated systolic
blood pressures noted with the use of Metabolife 356. The authors acknowledged
that the multi-ingredient nature of this product precludes a definite statement
regarding causation but argued that the findings were unlikely to be due to
caffeine. They did not discuss the other components of the supplement.
Ness J. Cardiovascular Effects of Ephedra. JAMA. 2004;291(13):1560. doi:10.1001/jama.291.13.1560-b