Fun Postscript to Fentanyl?! Yup.




I want to include a coda to the fentanyl story of the 1960s that we’ve discussed in our last two “The 1960s Today” columns. Though it involves one of fentanyl’s “children” of our March column, this coda is related to the constructive medical side of the fentanyl story (“Light Before Dark,” February) – something used mainly for good, not bad – to solve a problem, not create one.

One of the most powerful fentanyl analogues is something called “carfentanil,” synthesized near the end of our period in 1974 by a team of chemists at – you guessed it – Janssen Pharmaceutica, by this time a part of Johnson & Johnson.

Carfentanil concerns people and policymakers in the United States and around the world because it is now popping up in heroin samples and killing people more efficiently and mercilessly than ever probably because it’s 100x as potent as fentanyl

Unlike fentanyl, carfentanil never really had a career as a reputable medicine in surgery and pain management – that is, never had a reputable career with humans.

Nope, carfentanil and related substances were friends to animals, large ones.  As a tranquilizer, it allowed conservationists and zoologists to transport for example elephants, bears, rhinoceros and elk away from danger to safer habitats to thrive, away from poachers, drought, and even urban sprawl.

In the 1950s New Zealander Colin Murdoch developed a range of darts and guns to deliver tranquilizing substances from a distance to better study various kinds of goats and deer. Murdoch, along with University of Georgia researchers and others who separately developed what became some of today’s instruments known as “Cap-Chur” equipment, wrestled with the general problem in zoology and animal management of “Remote-Drug-Delivery Systems” (RDDS) or “chemical capture.” And its hazards.

Hawthoorn was in this region while Jane Goodall and Louis Leakey worked nearby, making contributions to primatology and paleoanthropology.

These big beasts are tough, but the science of sedation is a surprisingly delicate one. A common cause of injury or death in wild animals handled by humans is “capture myopathy” or CM. This is serious muscle overstrain resulting from a stress reaction in an animal either captured unsedated or captured through immobilization with a chemical agent – and transported. Subtlety and conscientiousness are therefore required in this specialized field.

And here our period shines again.

In the 1960s the Anglo-Dutch veterinarian-zoologist-conservationist, Antonie Harthoorn (1923-2012), headed a team in Kenya and Tanzania that refined chemical capture techniques a lot. From the sort of one-size-fits-all approach, he and his team centered at the University of Nairobi invented the M99 tranquilizer capture gun. Described in his wonderfully-titled book, The Flying Syringe (London, 1970), Hawthoorn used a new compound known as etorphine hydrochloride, a completely lab synthetic opioid developed the same year as fentanyl – 1960 – but 10x stronger per gram weight. But this isn’t Hawthoorn’s chief importance.

Hawthoorn spent his life – first in Kenya/Tanzania, then for decades after 1963 in South Africa – developing specific dosage levels of tranquilizers for thousands of animals that may have identical weight, but be of different species, and so react differently to sedatives. This culminated in his remarkable book, The Chemical Capture of Animals (London, 1976). Here was a guide to immobilization and transport of animals, starting with large mammals, but including valuable data on everything from birds to reptiles, amphibians – even fish ! – which are subject to the phenomenon of capture myopathy – and so they must have dosages of sedatives adjusted for morphology, metabolism and weight.

But wait . . . there’s more.

The era saw an explosion of interest in wildlife shows, specifically those set in Africa. These start with the story of George and Joy Adamson that became the wonderful lion movie Born Free (1960). Then a cascade of productions followed when film and TV producer Ivan Tors went to Kenya on vacation and visited the animal refuge set up by Hawthoorn and his first wife, fellow vet and conservationist, Sue Hart.

Fresh from series like Sea Hunt (1959-61) and in the midst the success of Flipper (1964-67), Tors was inspired to produce the full length feature film Rhino! starring a young Robert Culp in 1964 – centered around the capture gun technology he had seen at the Hawthoorn compound.  And straight away came still another TV series that became the popular show Daktari (Swahili for “doctor”) in 1966 and ran for four years.

As if this were not enough, Tors produced the TV series Cowboy in Africa with Chuck Connor 1967-8; and Aaron Spelling produced the British adventure film with the intriguing name Africa Texas Style in 1967. Through it all, zoologist Marlin Perkins became a household name with his Wild Kingdom supported religiously by the Mutual of Omaha Insurance Company from 1963-71.

And where is our fentanyl story in all this?

Well, Hawthoorn and his conservation peers opened the door to the responsible and precise use of Remote Drug Delivery Systems based on information and field testing. And these advances were part of what Ivan Tors so admired and portrayed on film. One of most potent of fentanyl’s children, carfentanil, synthesized at the end of our period in 1974, further refined this good cause of animal management.

Dangerous as it is for people – one thousand of a milligram will alter human consciousness – carfentanil serves for large animals the kind of constructive medical role as an anesthetic which fentanyl has served since the late 1960s.

No doubt about it – both fentanyl and carfentanil have become the bane of American and international law enforcement recently. Still, since 1986, carfentanil citrate has served quite a useful purpose in largely supplanting Hawthoorn’s  famous etorphine hydrochloride (m99) with a much faster intake time in animals. Since 1986, in fact, carfentanil has been sold under the brand name “Wildnil”(right), highly restricted in quantity (less than an ounce/per year total), but available to help veterinary professionals in the specialized work of restraining and managing the enormous, and sometimes cantankerous, “Big Five of Africa:” the leopards, rhinos, elephants, Cape buffalo, and lions. All in the cause of helping man live with nature’s beasts.

And the 1960s’ achievement had a hand in it: from manufacturing fentanyl at the start of our project to carfentanil at the end; and all the TV shows and movies in between.

Who would have known this if you were mired in conventional accounts of the years 1960 to 1975 !?  Wow.  We’re rolling.;

Until next month,
April 7, 2021

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