HEAT AND COCAINE DON'T MIX

Dallas Scientists Say Drug Inhibits Cooling, Sensation Of Fever

People who use cocaine in hot weather may die from an extra high they don't
even notice.

Even a small amount of the drug may blunt the body's ability to cool
itself, allowing a person's temperature to rise to dangerous levels. At the
same time, cocaine clouds the brain's perception of the heat, researchers
from the University of Texas Southwestern Medical Center at Dallas reported
last week.

That means recreational use during summer months - or at steamy clubs or
all-night dance parties - may be doubly dangerous, the scientists report in
the journal Annals of Internal Medicine.

"No one has ever shown in humans that cocaine alters internal body
temperature," says lead researcher Craig Crandall.

Researchers have known that cocaine deaths increase on hot days. A 1998
study published in The Journal of the American Medical Association, for
example, noted a steady rise in cocaine deaths in New York City when the
outside temperature rose above 88 degrees. The hotter the temperature, the
more fatal cocaine becomes.

The reason for this trend, however, wasn't clear.

"It's been one of the more confusing aspects of cocaine," says Dr. Glen
Hanson, acting director of the National Institute on Drug Abuse.

Doctors had hypothesized that cocaine simply revs metabolism, which raises
body temperature or puts a greater stress on the heart.

The scientists, from UT Southwestern and Presbyterian Hospital of Dallas,
may have found a deeper explanation. First, cocaine can boost the body's
internal temperature in warm conditions, even when a person is still. In
addition, the drug appears to impair the body's cooling mechanisms - namely
sweating and the dilation of blood vessels close to the skin.

But a user doesn't feel any warmer, and that's the critical problem, Dr.
Crandall says. "The perception of heating was very much impaired with the
cocaine."

The information could be a warning not only to casual drug users but also
to emergency personnel who would have to provide medical care to victims of
heat stroke. Cocaine use is responsible for more than 150,000 emergency
room visits each year.

Dr. Crandall and his colleagues came to these conclusions after conducting
experiments on seven volunteers, none of whom had ever used the drug.

The doctors dabbed amounts of the drug dissolved in saline in the
participants' noses - amounts less than a typical street dose, so small
that they shouldn't cause any of cocaine's well-known euphoric effects.
They repeated the experiment using the painkiller lidocaine.

The study subjects didn't know which dose contained cocaine.

The volunteers wore tube-lined full body suits that allowed the researchers
to manipulate the external temperature. The participants' body temperatures
rose when the scientists turned up the heat in the suit, but they rose
twice as much under the influence of cocaine.

Yet the volunteers complained about being hot only after getting the
lidocaine, even though the cocaine raised their body temperatures more.

That cocaine raises body temperature isn't surprising, but "I think it's
fascinating that people were unaware of their own body temperature," says
Dr. Peter Marzuk, a psychiatrist at the Weill Cornell Medical College of
Cornell University in New York. Dr. Marzuk led the 1998 study that found an
association between hot weather and cocaine overdoses.

Dr. Marzuk also points out that people often use cocaine with other drugs,
such as alcohol, that would heighten the dangers of heat. People who drink
alcohol often get dehydrated.

Research on the effect of drugs is important even when substances are
already known to be dangerous, Dr. Marzuk says. Smoking is a known cause of
cancer and heart disease, yet studies continue because research may offer
new insights into treatment and addiction prevention, he says.

The same is true of cocaine. "There are many things in life that are
dangerous, but it's very important we understand the mechanism," Dr. Marzuk
says.

The Office of National Drug Control Policy estimates that about 3.6 million
Americans use cocaine regularly.

Sadly, Dr. Crandall says, "the people for whom it is more important to know
it are those who least likely care, and those are the people who use cocaine."

In addition to Dr. Crandall, the study was conducted by Drs. Wanpen
Vongpatanasin and Ronald Victor.