From the Division of Clinical Pharmacology and Experimental Therapeutics, Medical Service, San Francisco General Hospital Medical Center; and the Departments of Medicine, Bioengineering and Therapeutic Sciences, University of California, San Francisco — both in San Francisco.
Supported by grants from the Flight Attendants Medical Research Institute and the National Institute on Drug Abuse (U.S. Public Health Service grants DA02277 and DA20830).
Disclosure forms provided by the author are available with the full text of this article at NEJM.org.
I thank Marc Olmsted for editorial assistance on an earlier version of the manuscript.
