#5 - JRL 6524
Russian gas looks like deadly cocktail of common anaesthetics

PARIS, Oct 30 (AFP) - Fentanyl and halothane, the compounds now said to have been used in the mystery gas that ended the Moscow hostage siege, are common general anaesthetics used separately in surgery or sometimes together for complicated heart operations.

But in extreme doses they can result in liver damage, lung seizure, vomiting, incapacitation -- and death.

Confirmation from Russian Health Minister Yury Shevchenko on Wednesday that "a fentanyl-based substance was used", along with tests on released German hostages that showed traces of halothane pointed to a potent cocktail having been employed.

Together, the substances would have delivered a one-two punch: fentanyl to first deaden the brains of the hostages and their bomb-toting captors, then halothane to push them into unconsciousness.

Fentanyl appears to have been the first agent pumped into the room, probably in aerosol form. Some of the hostages described seeing a grey cloud fill the theatre before the assault to free them.

A synthetic narcotic of the opiate family, fentanyl is hundreds of times more potent than morphine, with a "rush" similar to heroin.

First used by the US military, it was found to have a short-term effect on the brain that helped treat combat wounded with major blood loss.

It was introduced into clinics in 1968 as an intravenous anaesthetic and today it is often used to prepare patients for serious operations, frequently in open heart surgery.

It is also available as a strong painkiller for cancer patients and, in very small doses, in medical lollipops for ill children. An illegal street version nicknamed "China White" became available from 1979.

In high doses, fentanyl can cause people to stop breathing and lapse into a coma -- conditions seen in many of the hostages carried out of the Moscow theatre.

Variants such a lofentanyl, which is 60 times stronger, have been researched in the United States as non-lethal crime-fighting weapons because of their ability to incapacitate suspects within seconds and the ease with which an antidote -- naltrexone -- can reverse their effects.

But fentanyl and its sister compounds lose their potency quickly, which means that another, longer-acting knockout product would have had to have been used.

Halothane could have been that product. Traces of it were detected in two surviving German hostage being treated in Munich.

Odourless and non-combustible, and working through the nervous system, its advantages over nitrous oxide and ether were evident from its development in 1956.

But in some cases, or in large doses, it can lead to liver poisoning and respiratory failure.

A study in the British medical review The Lancet in 1999 warned that children could also suffer heart problems under halothane, leading to a government alert to dentists. And the World Health Organisation said it should only be used with artificial breathing gear on hand.

Using a massive amount in a closed space, such as the Moscow theatre, would have been gambling with lives, experts say.

"If you multiply normal halothane doses by 100 or by 1,000, you don't put people to sleep -- you kill them," the head of pharmacology at Angers hospital in France, Professor Bertrand Diquet, said.

US officials commenting on the use of fentanyl in Moscow said such a substance would not constitute a violation of the 1997 treaty banning the use of lethal chemical weapons, because it allows the use of non-lethal chemicals for law enforcement and riot control purposes.

A former US intelligence official said Soviet scientists had worked hard during the Cold War on "bio-regulators", agents that could alter mass behavior and even put entire cities to sleep.

A total of 119 hostages died during the three-day ordeal, nearly all of them from inhaling the gas pumped into the theatre to knock out the hostage takers.

Up to Wednesday, Russian authorities declined to identify the gas beyond saying it was a sort of anaesthetic, earning criticism from doctors who had to guess what sort of treatment to give.