RayArt Graphics/ Alamy Stock Photo
A coroner has raised concerns about awareness of the impact of smoking reduction and cessation on clozapine levels, following the death of a patient.
Deborah Lakin, assistant coroner for Worcestershire, wrote to Herefordshire and Worcestershire Health and Care NHS Trust in a ‘Prevention of future deaths report’ (PFD), published online on 28 July 2026, following the death of Jack Burton, aged 29, in October 2025 from clozapine toxicity.
The coroner wrote: “Mr Burton had been prescribed clozapine for schizophrenia, and he was a smoker, who had been regularly advised that any cessation of smoking would increase clozapine levels. Mr Burton stopped smoking tobacco on or before 4 October 2025. On the evidence it is likely that this led to a fatal increase in clozapine blood levels.
“He died while on holiday in North Yorkshire and the results of the post-mortem and toxicology indicate his death was due to clozapine toxicity. His sister confirmed that Jack was a heavy smoker and was taking 525 mg clozapine nightly as prescribed, which is the correct dose when he is smoking; however whilst they have been on holiday, he did not smoke.
“If he had stopped or reduced his smoking, he should have informed his psychiatrist to reduce the amount of clozapine he was taking, as this could cause seizures.”
During the inquest, the coroner noted that she had received “inconsistent accounts” by two consultant psychiatrists about the relevance of smoking reduction, rather than cessation, which she said was “attributable to there being no guidance available to doctors on this issue”.
In a written response to the PFD, published on 25 June 2026, the Herefordshire and Worcestershire Health and Care Trust said that its clozapine treatment guidelines were in date and available on the trust’s intranet site. It also said that the guidelines made clear reference to the impact of both smoking cessation and reduction.
“If a patient reduces their level of smoking tobacco, the level of clozapine available in their body will rise. This change can be dramatic and potentially result in overdose or toxic plasma levels of clozapine,” the response said.
The trust also highlighted national guidance available online, which said that “individuals stopping or reducing cigarette smoking are at risk of severe toxicity”.
Commenting on the coroner’s concerns, David Taylor, director of pharmacy and pathology at the Maudsley Hospital and professor of psychopharmacology at King’s College London, said that relevant guidance is freely available to NHS England healthcare professionals in the Maudsley prescribing guidelines, for which he was lead author.
The effect of smoking on clozapine is “well-known”, he said, adding that “you would certainly expect and assume that a mental health pharmacist would know this”.
Taylor also noted that “even very low frequency smoking, so five or fewer cigarettes a day, has a significant effect on CYP1A2”, which is the enzyme that reduces plasma clozapine levels.
In addition, the coroner wrote: “[There was] 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.”
“[It is] standard practice for trust practitioners to monitor for any side effects of clozapine, and this is completed by using the Glasgow Antipsychotic Side-effect Scale,” the trust’s response said.
“The outputs from this are then recorded with the patient electronic health record and followed up as clinically indicated.”
Following the coroner’s report, the trust said it had re-issued both documents to the mental health clinical workforce, adding that “follow-up actions will be undertaken to ensure that both newly appointed and existing staff are aware of, and comply with, the guidelines”.
Some patients and clinicians have previously called for clozapine monitoring and re-prescribing rules to be relaxed.
