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Russian gas clues point to cocktail
Further evidence about the Moscow knock-out agent suggests a mixture of anaesthetic and opioids
Further clues to the identity of the knock-out agent used to end the Moscow hostage crisis have emerged, indicating that a likely candidate is a
cocktail of an opioid narcotic such as fentanyl supplemented by halothane, a common anaesthetic. The two are commonly used together in clinical
The Russian authorities are maintaining their silence on the identity of the gas, which they used to incapacitate the Chechen hostage-takers on
Saturday. But the gas is believed to have killed all but two of the 117 hostages who died. The first funerals have already been held.
Late on Tuesday, doctors in Munich reported that chemical analysis had identified halothane in blood and urine samples taken from two surviving German
hostages within 24 hours of the rescue.
But David Whittaker of the Association of Anaesthetists of Great Britain cautions that the two may have received halothane as an emergency treatment
for bronchospasm induced by inhaling vomit, which happened to many hostages. If this true, it is probable that an opioid was used alone.
Peter Hutton, president of Britain's Royal College of Anaesthetists, adds: ìHalothane would take several minutes to get people even partially
asleep." The gas used in Moscow rendered hostage-takers unconscious much more quickly, preventing them from donning gas masks or detonating their
However halothane in the agent would at least agree with what little Russian officials have said ñ ìit was a medical gas used in anaesthesiologyî.
Doctors at the US embassy in Moscow say the two American survivors they examined had the telltale signs of opiate intoxication. Moreover, Moscow
doctors have reportedly been treating survivors successfully with naloxone, which blocks the action of opiate drugs. And breathing failure and
inhalation of vomit, said to be the most common cause of death in the hostages, are caused by opiates.
ìThere is already an inhalable opiate available ñ fentanyl, a short-acting, rather potent narcotic,î says Alan Zelicoff, a chemical and biological
warfare expert at Sandia National Laboratory in New Mexico, US. ìThe clinical utility of this drug is that it acts very quickly.î
Fentanyl is commonly combined with halothane in order to minimise halothaneís toxic side effects. And halothane may have been used to extend the
effect of the agent, as the fentanyl wore off. But at high doses fentanyl alone may have been sufficiently long lasting. Both compounds must be
administered as an aerosol suspension ñ tallying with the ìgreyî mist reported by some hostages.
The most likely cause of the terrible number of hostage deaths is the side effects of fentanyl, say observers. Martin Furmanski, a medical historian
in Newport Beach, California, says administering enough of an opiate drug to cause rapid anaesthesia almost always causes a patient to stop breathing
ñ not a problem in a fully-equipped operating theatre, but a tragedy in the Moscow theatre.
Similar opioids are used in tranquilising darts for anaesthetising large animals. In these cases, the lethal dose is just six times greater than the
dose needed for anaesthesia.
That implies that if the Moscow hostage-takers were exposed to enough of the mixture to knock them out within one minute, hostages who kept breathing
it would have acquired a lethal dose within six minutes.
If this analysis is correct, notes Furmanski, the poor physical condition of the hostages, or a dosage miscalculation is not necessary to explain the
mass deaths. ìIt was probably inevitable that many hostages would die if the aerosol opiate concentration was high enough to cause rapid
unconsciousness in the terrorists,î he says.
Short of Russian officials naming the agent, the next information is likely to come from the examination of the remains of two US hostages who died,
and clothing from a British family, now being examined at the UKís chemical defense lab at Porton Down. However, rapid breakdown of short-acting
opioids such as fentanyl might mean analysts will have to look for longer-lived breakdown products of the drug.
copyright 2002 Reed Elsevier