Toxicology
Absinthe: A Brief History of the Green Fairy
by Andrew J. Hoene, MD & Timothy B. Erickson, MD on October 29, 2011
Print
 

Paramedics are called to a college fraternity Halloween party where a large cauldron of “green witches brew” was being served. Several students are found intoxicated with altered mental status and hallucinations. Two male freshman students suffer generalized tonic-clonic seizures en route to the ED.

alt 

Absinthe has two main ingredients: alcohol and oil of wormwood. Artemesia absinthium, commonly known as wormwood, is a plant in the compositae family (sunflowers and daisies) indigenous to Eurasia and North Africa. Humans have a long history with wormwood, using it for various ailments. Its first documented medicinal use occurred in 1552 B.C. when Egyptians used wormwood as an anti-helminthic. Pliny the elder later championed it as a wine fortification in the first century AD. The advent of steam distillation in the 1500s allowed for the creation of potent extracts of wormword. In 1789 Dr. Ordinaire, developed a recipe for an alcoholic beverage based on the dried leaves of wormwood. The drink quickly gained popularity among the French and in 1798, the Pernod Fils distillery began commercial production of the drink we now know as Absinthe.

Following the upheaval of the French revolution, a newly empowered upper class looked for an alternative to the traditional spirit of wine. Absinthe was the benefactor of this shift, becoming the choice drink of the flourishing bohemian lifestyle. Purported to stimulate creativity and possess aphrodisiac properties, it was the preferred drink for the artesian class.  Artists Vincent van Gogh, Pablo Picasso, Paul Gauguin, Edward Manet, Edgar Degas, and authors Oscar Wilde, Emile Zola, Paul Verlaine, Arthur Rimbaud, and Ernest Hemmingway all imbibed the potent green liquor with regularity.

In the setting of global movement towards temperance in the late 1800s, Absinthe was branded as “madness in a bottle” and blamed for inducing insane and criminal acts. The term absinthism was coined, describing a form of alcoholism characterized by delirium, hallucinations, tremors, and seizures. Absinthe was serially banned by most of the European countries, the US, and finally by France in 1915.

Absinthe traditionally contains 75-80% ethanol; is 150-160 proof, twice that of most standard whiskeys. The wormwood plant contains 1-2% volatile oil by weight; 70% of this oil is thujone (composed of α and β versions). Traditional Absinthe contained 260-350ppm thujone. Today’s watered down version must contain less than 10ppm by law.

Thujone, an aromatic hydrocarbon structurally similar to THC (the active component of marijuana), has been linked to mystical effects of Absinthe. Thujone is also present in the liquors vermouth and chartreuse. It is known to have analeptic properties, produce mood elevation, work as an anti-depressant and can also lead to anxiety and increased alertness. This is in stark contrast to ethanol, which is a depressant, anxiolytic, and amnestic. Thujone has been shown to have some activity at both nicotinic and muscarinic receptors, but these effects are largely insignificant. The majority of its effects come from inactivation of GABA receptors. Thujone is a non-competitive GABA-α chloride channel receptor blocker. Blocking GABA, the chief inhibitory neurotransmitter in the brain, leads to activation of neurons. Ethanol, on the other hand, is a GABA-α chloride channel receptor enhancer, leading to neuronal inactivation. Hence, thujone and ethanol have completely antagonistic properties. Thujone is metabolized by the cytochrome p-450 system, and its metabolites are renally excreted.  

It has been postulated that the thujone levels in traditional absinthe would have had a definite intoxicating effect. The effect of thujone in present day absinthe is less clear. The thujone content of legal absinthe today is unlikely to cause acute toxicity. However concentrated oil of wormwood is still commercially available via the Internet, and acute overdoses can still occur.

Paradoxically, the toxicity of thujone mirrors that of alcohol withdrawal. Autonomic excitation can progress to acute encephalopathy, unconsciousness, decreased seizure threshold, and tonic-clonic seizures. Permanent CNS damage may occur with repeated exposures, leading to insomnia, tremors, nightmares, dizziness, delirium, and paralysis.

Treatment of acute thujone intoxication is typically supportive care with benzodiazepines for seizure control.  Chronic use may require enrollment into a detoxification program.

Case outcome:
Both college freshmen have limited tonic-clonic seizure responsive to supportive care and intravenous benzodiazepine administration in the ED. After 48 hours of observation in the intensive care unit, both patients are discharged home and recover uneventfully. Analysis of the “green witches brew” served at the party reveals large concentrations of absinthe containing oil of wormwood and thujone.

References