Two existing medications cooled core body temperature in animals after stroke and reduced brain damage. A small human trial showed limited effect due to slow delivery. Researchers are now planning a follow-up study with faster infusions.
Researchers tested promethazine and chlorpromazine on mice and rhesus monkeys after inducing strokes. The drugs lowered body temperature, reduced glucose metabolism in cells, and decreased brain damage. Treated monkeys also showed improved limb function.
In a clinical trial of 32 people, the same drugs lowered temperature by only 0.3°C and did not reduce stroke damage. The team attributed this to slow 12-hour infusions that failed to achieve effective drug levels quickly.
The medications, already approved for hay fever and psychosis, act on the central nervous system without causing shivering. A new trial will test one-hour infusions to determine if faster cooling improves outcomes.
