Pills that plunge the body and brain into hypothermia could reduce disability and deaths from strokes.
uncertain
that → plunge → strokes
People who have a cardiac arrest, where the heart suddenly stops beating properly, depriving the brain of blood and oxygen; or who damage their spinal cord in a car crash, could also benefit from a form of the treatment with everyday tablets – paracetamol, aspirin or ibuprofen.
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who → have → tablets
Ideally, paramedics will administer the drugs when they arrive on the scene.
asserted
they → administer → scene
As Samir Ayoub, a senior lecturer in pharmacology at the University of East London, who has been investigating this approach, explains: ‘Our end goal is that critically ill patients receive drug-induced hypothermia before they even get to hospital because the first hour when someone is in cardiac arrest, spinal injury or stroke is crucial.
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someone → investigate → arrest
‘We know that patients need to be cooled down quickly to have the best chance of a good outcome.’
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patients → know → outcome
The idea of using hypothermia to help the body heal isn’t new.
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body → use → hypothermia
Therapeutic hypothermia – lowering the body temperature from around 37C to between 33-34C for 12 to 24 hours – is widely used to treat traumatic head injuries, spinal cord injuries, cardiac arrests, as well as for newborns who have been deprived of oxygen at birth.
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who → lower → birth
It slows the brain’s metabolic rate, reduces inflammation and stops brain cells dying – increasing the chance of a full recovery.
Samir Ayoub, a senior lecturer in pharmacology at the University of East London, believes that cocktails of drugs may be needed to cool the body enough for hypothermia to set in
But current cooling techniques involve placing cooling bags directly on the skin or infusing cold saline solution straight into the patient’s bloodstream.
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techniques → slow → bloodstream
This means they can only be performed in hospital, potentially costing valuable time during the so-called ‘golden hour’, the period when treatment for patients who have had a stroke, for example, means they are much more likely to avoid long-term disability.
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they → mean → disability
Early treatment of strokes also increases the odds of survival.
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treatment → increase → survival
A new study involved two medicines that have been safely used since the 1950s to treat other conditions.
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that → involve → conditions
Scientists at Capital Medical University in Beijing showed that, when administered together, chlorpromazine (normally used for schizophrenia and severe nausea) and promethazine (typically given for allergies and nausea) significantly lowered the body temperature of mice and primates.
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chlorpromazine → show → mice
Crucially, the combination also reduced damage to the brain after a stroke.
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combination → reduce → stroke
The researchers followed this up with a clinical trial involving 32 people who had just had ischaemic strokes – where a clot travels to the brain and blocks its blood supply.
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clot → follow → supply
At the highest dose, body temperature dropped around 1C.
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temperature → drop → dose
However, the reduction was small and not enough to trigger hypothermia as it had in mice and primates.
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it → trigger → mice
This may be because humans have a lower surface area to body mass ratio – meaning they have a relatively small amount of skin compared to their weight – which means it takes heat longer to dissipate through the skin.
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it → have → skin
Therapeutic hypothermia slows the brain’s metabolic rate, reduces inflammation and stops brain cells dying, which can increase the chance of a full recovery
‘
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which → slow → recovery
How it works is still not completely understood but therapeutic hypothermia almost certainly protects the brain from further damage,’ David Baker, an emeritus professor of neuroimmunology at Queen Mary University of London, told Good Health.
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Baker → work → Health
One theory is that the drugs act on the thermostat in the brain to prevent shivering, the body’s way of warming itself up – this is something that cooling bags and saline solutions do not curb.
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bags → act → that
Professor Baker adds: ‘Drug-induced hypothermia may be preferable to physical cooling because the body is programmed to resist cold, and shivering is a process to create heat.
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shivering → add → heat
Inside-out cooling [with drugs] would stop these mechanisms.’
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cooling → stop → mechanisms
Drugs may also widen blood vessels to release heat and reduce the metabolic rate – the burning of energy.
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Drugs → widen → energy
The downside of physical cooling is that it can trigger a spike in stress hormones, a slow heart rate, low blood pressure and changes to white blood cells that increase the risk of infections.
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that → trigger → infections
It can interfere with blood’s ability to clot too, which makes bleeds more likely.
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bleeds → interfere → ability
The hope is that the inside-out treatment will help with this too.
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treatment → help → this
Meanwhile, other researchers are looking at whether household medicines used for fevers, such as paracetamol, aspirin and ibuprofen, could also cool the body rapidly when needed.
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medicines → look → body
Paracetamol can lower body temperature by as much as 1C for up to four hours at a time, research by Samir Ayoub found.
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research → lower → Ayoub
In a review he published in the journal Temperature in 2021, he concluded it was because the popular painkiller blocks an enzyme called COX-1, which is involved in producing prostaglandins – hormones responsible for raising the body’s temperature.
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which → publish → temperature
Samir Ayoub believes that cocktails of drugs may be needed to cool the body enough for hypothermia to set in.
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hypothermia → believe → body
In addition, ‘if you only used one drug, you would have to give such a high dose that it might end up having a detrimental effect’, he says.
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he → use → effect
‘We know higher doses of drugs can induce toxicity even if it is only short term.
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it → know → toxicity
For example, paracetamol can cause liver damage if given beyond the recommended therapeutic dose.’
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paracetamol → cause → dose
Other experts caution that there is a long way to go.
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experts → caution → ?
The scientists in China only lowered human body temperature by less than 1C, ‘too small to achieve a sufficient cooling effect’, said Malcolm Macleod, a professor of neurology and translational neuroscience at the University of Edinburgh.
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Macleod → lower → Edinburgh
‘The prospects of this doing anything are low indeed.’
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this → do → anything
The Aporia
