The only way I would feel safe abusing this shit is if gasbo was hanging around to help out

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Thanks for the vote of confidence quale
Halothane - hell - i don't even use it on my patients (actually - i tell a small lie - i have used it twice in 10 years for a very specific indication) - but yeah - the main reason i don't use it - its too dangerous !
Halothane - is 2 bromo 2 chloro 1,1,1 tri-fluroethane - a colourless liquid hydrocarbon with a very sweet (almost nauseatingly sweet) smelling odour used in anaesthesia as a volatile agent. It contains a thymol preservative (0.01%) to help prevent decompostion in light.
Danger Point #1:
It has a Saturated Vapour pressure of 243mmHg at 20 deg Cel. which means that a 1 atm pressure (sea level), it can exist in a 30% concentration. This property is really important - because if you take the lid off the stuff and sniff it - 30% of the gas you entrain will be halothane.
So how much is required to put you to sleep ?? well - about 0.75% (end-tidal equilibrated) is equal to 1 MAC (ie. the minimum alveolar concentration required to keep 50% of the study population from reacting to a standard surgical stimulus (ie. a mid forearm incision !). Therefore you can overdose by a factor of 30 without the correct technology to administer it !
In an anaesthetic environment we use specific vapourisers which are accurately calibrated to deliver minute concentrations of the vapour - in 0.2% aloquots up to a maximum of 6% - but if the dial was left on that - then you would die and reasonably quickly (within 30min).
Danger Point #2
Halothane is metabolised by the mixed function oxidase system in Endoplasmic reticulum in the liver. It has been shown to induce CYP450 in rats (weakly), and does cause liver enzyme induction in humans. 11-20% of the drug is metabolised (when inhaled concentration is 1%), and up to 50% metabolised when subanaesthetic concentrations are used.
That might not sound like a lot, but one of the ideal properties of a volatile agent is minimal (no) metabolism - so it falls far short of ideal. The newer agents that I use (and prefer) have less than 0.02% metabolism. The advantage being the offset of the drug is by washout with breathing fresh source.
So what's the problem with metabolism of halothane !
Well - it can undergoe oxidative metabolism (main one) or the reductive metabolism.
An entity exists known as halotahne hepatitis / hepatotoxicity. It is an adverse reaction to the drug characterised by a cetrilobular necrosis of the liver - the mechanism is still alittle unlcear but is likely multifactorial involving hypersensitivity, hypoxia, reactive intermediates, and secxondary to its metabolites (protein-hapten complex with immune consequences).
It appears 2-5 days after exposure and is marked by fever, nausea, vomiting, jaundice, arthralgia, rash and an eosinophilia. While it is rare (1:6000-1:35000) is it disasterous - like total liver failure and death ! It can occur on repeat exposures - so just becuase you have had it once - doesn't mean it will be ok then next time. The only treatment for the full blown severe form is liver transplant !
Danger Point #3
It sensitises the myocardium to the arrhythmogenic properties of catecholamines ! That means not only your natural endogenous adrenaline / noradrenaline, but also to any other exogenous adrenaline. Therefore if you had effects of stimulants (eg. Speed, E, Cocaine) at the same time, then you run the risk of VF ! In one of my patients that I used it on had this complication - but lived ! fortunately due to early management and also to about 10 000 Volts (360Joules) applied to his nipples ! hehe
Danger Point #4
It causes a dose dependent depression in respiration and you respiratory protective reflexes (ie. you don't cough and clear your airway like you do when awake). Plus it is associated with nausea and vomiting on emergence. Therefore with unsupervised use - can lead to aspiration of your carrots down your right main bronchus ! (mortality in supervised unit - 20%; mortality when un-supervised ..... you figure it out !)
I know all docs say - only with medical supervision - but this one is a real doozy !! Don't even be tempted to try it - it doesn't give you the slightest buzz what-so-ever either.