Urgent warning issued to anyone taking common medication during heatwave

Patients taking common medications for their mental health have been warned to take care during the UK’s sweltering heatwave. Dr Daniel Harwood, chair of the Royal College of Psychiatrists’ Planetary Health and Sustainability Committee, issued advice amid fears that some people may be particularly vulnerable to the effects of high temperatures on health.

He said: “With the Met Office issuing a ‘risk to life’ weather warning for parts of the UK, people with mental health conditions and taking medications including antidepressants, mood stabilising or antipsychotic medications must take special care. We know people with mental health conditions — especially severe mental illnesses such as schizophrenia and bipolar disorder — often have worse underlying physical health than the general population, so they may be more vulnerable to sunburn, dehydration and heat stroke.”

Many common medications used for mental health affect the hypothalamus — the region of the brain responsible for regulating your internal body temperature.

This can impact the body’s ability to recognise when it is overheating and to trigger natural cooling mechanisms. Some medications also result in a dulled sense of thirst, increasing the risk of dehydration.

Dr Harwood said: “Becoming dehydrated can be a particular problem at the moment, as it can increase sensitivity to the effects of some medicines, such as constipation for people on clozapine.

“People taking lithium also need to drink plenty of fluids to support their kidney function.”

Dehydration can cause the concentration of lithium in your bloodstream to rise, pushing it out of the safe target dose range and risking lithium toxicity.

There is limited but growing research showing increased risks to people with mental illness during extreme heat, including a 1.5% rise in suicide incidence and 9.7% rise in psychiatric hospital admissions, according to the Royal College of Psychiatrists.

Dr Harwood added: “I’d urge all people, but especially those with a mental illness, to make a concerted effort to stay cool and hydrated, use plenty of sun block and avoid going out during the hottest parts of the day.

“And if you feel physically unwell, please contact your pharmacy, mental health team or seek urgent medical advice.”

Common antidepressants prescribed on the NHS include fluoxetine, sertraline, citalopram and paroxetine.