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New hope for preventing strokes in cocaine addicts
Cocaine users place themselves
at high risk of suffering strokes, even six months after using. Thankfully,
a group of medications called dihydropyridine-class calcium channel antagonists
show promise at stopping cocaine-induced strokes.
Addiction researchers at The University of Texas (UT) Health Science Center
at San Antonio, the UT Houston Health Science Center and the UT Southwestern
Medical Center at Dallas present these conclusions in the lead article
of this month's American Journal of Psychiatry. The scientists, Bankole
A. Johnson, M.D., Ph.D., and Nassima Ait-Daoud, M.D., of the UT Health
Science Center at San Antonio, Michael D. Devous Sr., Ph.D., of UT Southwestern,
and Pedro Ruiz, M.D., of UT Houston, reviewed 34 years of studies on the
subject and examined them in light of today's neurochemical understandings.
The article highlights the researchers' own groundbreaking work on the
development of isradipine, a calcium channel antagonist, as an effective
weapon for treating cocaine-induced stroke. "We did the main work
on isradipine and have reanalyzed those findings," said Dr. Johnson,
the William and Marguerite S. Wurzbach Distinguished Professor at the
Health Science Center. "More studies are needed of this medication."
Cocaine use increases levels of the neurochemical dopamine and results
in reduced arterial blood flow to the brain. This obstruction of blood
flow is known as cocaine-induced cerebral ischemia. Isradipine, which
shows promise as a therapeutic agent for this form of ischemia, acts by
restoring and maintaining blood flow to dopamine-rich brain regions.
"Taking cocaine causes brain damage," Dr. Johnson said. "This
medication provides new hope for preventing and treating one of the major
causes of death and disability in cocaine addicts."
Dr. Johnson is professor of psychiatry and pharmacology, deputy chairman
for research in the department of psychiatry, and chief of the alcohol
and drug addiction division. He directs the Southwest Texas Addiction
Research & Technology Center (START), a comprehensive research site
near the Health Science Center in San Antonio. He is one of the country's
foremost researchers of addictive behavior, particularly in the areas
of alcoholism and cocaine abuse. The START Center officially opened last
"The practical demonstration of the treatment for cocaine-induced
strokes is ongoing at the START Center," Dr. Johnson said. "This
continues five years of painstaking research to find effective medications
with which to help addicts who are at high risk from suffering strokes.
Clinical trials of isradipine are the next step, since we now have proof
of concept that it works."
Users may place themselves at up to 14 times greater risk of cocaine-induced
stroke. Researchers have observed a rising tide of strokes in addicts
since the earliest verified cases in the late 1970s. According to a 1997
National Institute on Drug Abuse household survey, 1.5 million Americans
were cocaine users. The Office of National Drug Control Policy estimates
the number at 3.6 million when data on under-represented users are taken
into account. Emergency room visits related to cocaine use are estimated
to be in excess of 150,000 per year.
The researchers are optimistic that what they have learned will have important
implications for the treatment of ischemic strokes due to other causes.
Grants DA-13002-01 and DA-12191 from the National Institute on Drug Abuse
funded their studies.
The American Journal of Psychiatry is the most widely circulated journal
of psychiatry in the world. It is the official journal of the American
Contact: Will Sansom,
(210) 567-2570 Alternate: Aileen Salinas