A “heavy smoker” died after giving up cigarettes, as the decision caused a medication that he was taking to become toxic.

Jack Burton lived with paranoid schizophrenia and had been prescribed clozapine, an anti-psychotic medication, by his community psychiatrist.

The 29-year-old took 525mg of the drug every night, which was the “correct dose” for a smoker as cigarettes lessened the effects of the medication.

However, the Worcester man’s decision to stop smoking while on holiday in North Yorkshire meant that his normal dose was too high.

That led to a dangerous increase in the levels of clozapine in his blood, and he died.

A coroner has now warned of the effects of quitting smoking while on the medication after it was found that there is “no guidance available to doctors on this issue”.

The inquest into Mr Burton’s death heard that he passed away about three days after stopping smoking.

His cause of death was ascertained as clozapine toxicity.

Worcestershire assistant coroner Deborah Lakin said that if Mr Burton planned to stop smoking, he “should have informed his psychiatrist to reduce the amount of clozapine he was taking” as too high a dose “could cause seizures”.

His sudden death and a lack of guidance on the issue led Ms Lakin to write a prevention of future deaths report.

She said that she is concerned that there is a risk of more people dying without better guidance surrounding clozapine dosage and smoking.

In the course of the inquest, it remained unclear whether Mr Burton had asked questions about his medication and whether the correct information had been provided.

Ms Lakin said that during Mr Burton's inquest “there were inconsistent accounts provided to me by two consultant psychiatrists, about the relevance of reduction in smoking, rather than cessation of smoking, attributable to there being no guidance available to doctors on this issue”.

She continued: "The evidence revealed that there is no guidance on any standardised practice available to practitioners relating to asking questions and recording answers given when discussing possible symptoms of side effects of the medication.

"Practitioners can therefore make no record if no information is provided, which does not indicate whether questions were asked."