Addressing the oft-repeated mantra – “you don’t know how anaesthetic works”
When considering homeopathy
, an obvious bone of contention is the lack of a plausible molecular mechanism
When proffering this as a reason why homeopathy is not feasible, a homeopath will typically counter with “well what about anaesthesia – we don’t know how that works either.”
So lets explore this a little further…
“General anaesthesia is administered each day to thousands of patients worldwide. Although more than 160 years have passed since the first successful public demonstration of anaesthesia, a detailed understanding of the anaesthetic mechanism of action of these drugs is still lacking.” So states the opening gambit of an excellent and fairly recent review of the potential receptors for general anaesthetics.
Kopp Lugli, A., Yost, C.S. and Kindler, C.H. (2009) “Anaesthetic mechanisms: update on the challenge of unravelling the mystery of anaesthesia”. European Journal of Anaesthesiology, 26(10), p 807–820
A general anaesthetic has to do three things: cause immobility, amnesia and unconsciousness. Many potential molecular targets are being researched – these are summarised in the table below.
Taken directly from Kopp Lugli, A., Yost, C.S. and Kindler, C.H. (2009) “Anaesthetic mechanisms: update on the challenge of unravelling the mystery of anaesthesia”. European Journal of Anaesthesiology, 26(10), p 807–820. Fair use claimed.
We don’t know for sure what all the molecular targets are, but Franks, N.P. (2006) “Molecular targets underlying general anaesthesia” Br J Pharmacol. 147(S1): S72–S81, is a decent review of what is known about the molecular mechanism of two types of Anaesthetic, propofol and etomidate, and their interaction with the GABA-A receptor. The GABA-A receptor is a ligand-gated ion-channel, a complex of proteins that allows ions (in this case Chloride ions) to cross an otherwise impermeable membrane. GABA-A receptors are found in most areas of the brain. Propofol and etomidate are positive allosteric modulators of the ion channel – they bind at a site on the ion-channel distinct from the pore through which the ions pass and make the ion-channel more easily openable, and Cl- ions can flow freely accross the membrane. This will lead to hyperpolarization of the neurons, which in turn, inhibits neurotransmission, which eventually leads to the anaesthetic effect.
Science doesn’t know the precise ordering of molecular events that leads to sucesful anaestheisia – but it is working on it – and it is making progress. But for all anaesthetics we have “leads” – potential, rational, explainable targets for their mode of action.
So we actually know a lot more about the mechanism of action of anaesthetics, than we do about homeopathy.
Now lets look at the formulation of a typical general anaesthetic.
Propofol is distributed as Diprivan – a 1% solution in combination with various inert stabilisers and anti-microbial agents.
The dosing guidlines for Diprivan states: “adult patients under 55 years of age and classified as ASA-PS I or II require 2 to 2.5 mg/kg of DIPRIVAN Injectable Emulsion for induction when unpremedicated or when premedicated with oral benzodiazepines or intramuscular opioids. For induction, DIPRIVAN Injectable Emulsion should be titrated (approximately 40 mg every 10 seconds) against the response of the patient until the clinical signs show the onset of anesthesia. ”
Lets assume we have a 100kg adult, and we are going to dose them at 2.5 mg/kg.
So that’s a total of 2.5mg x 100 = 250mgs of Diprivan.
The molecular weight of propofol is 178.271 g/mol.
This is 0.25g / 178.271 = 0.00140235 moles of Diprivan.
Multiply this by Avagadro’s Constant and you discover that this 250mgs has got 8.44×10^20 molecules of pharmacologically active ingredient.
Contrast this with a Homeopathic anaesthetic, which would have zero molecules of pharmacologically active ingredient.
Interestingly enough, given all the things homeopathy claims to cure (cancer, AIDS, Homosexuality, etc) – a cursory piece of googlage actually reveals that one of the few things homeopathy doesn’t claim to do is general anaesthetic – fear of pain is a great leveller, I guess.
(If you can find a reference to a Homeopathic Anaesthetic – please leave a comment below!)
However, homeopaths naturally claim that homeopathy can help with after effects of anaesthesia and surgery – after effects which coincidentally, will resolve naturally more often than not.
This reference sheet entitled “Homeopathic support during surgery” is particularly shocking.
The first thing to note is that it states: “Use 30c potency for these acute treatments.”
As previously established – 30c potency contains zero pharmacologically active molecules.
Of all the treatments outlined by this sheet – the most dangerous and irresponsible are those that detail treatment for symptoms of surgical site infection (SSI).
“Hepar Sulph wounds that have become weeping and pustulent”
“Pryogen indicated when there is necrosis, gangrene or dead flesh, in the wound”
That is exceptionally irresponsible – Between 5% and 10% of people who undergo an operation suffer from an SSI. Dangerous pathogenic bacteria such as MRSA and Clostridium difficile can thrive in the wounds left after surgery, and if left unchecked, infection can be fatal. The correct treatment for an SSI is antibiotics.
If anyone were to rely on homeopathy rather than conventional antibiotics, they would be putting their lives in jeopardy.