This is despite the risk having been highlighted in at least two prescriber updates published by MedSafe over the past decade.

A recommendation will now be made for Pharmac to consider stopping subsidy of the drug beyond six months’ use to “special authority” approvals only, as a way to restrict its availability.

Following his death in 2019, the man’s wife complained to the HDC, primarily to help prevent “another avoidable death as a result of a lack of professional knowledge about the adverse effects of the medication”.

He was initially prescribed the medication by a specialist at a spinal unit of a district health board.

It was successful in treating his symptoms, so his GP and a urology registrar at another public hospital continued to prescribe it, without ensuring the man understood the risks of long-term use. The pharmacy also dispensed the medication without advising the man of the risks, Cooper found.

He had been taking the drug for about 28 months between 2017 and 2019 and was never made aware of the known risk of pulmonary disease from its long-term use.

About six to eight months after starting the medication the man developed a mild and dry cough, but as neither he nor his wife were aware that this could be related to the nitrofurantoin, they did not raise any concerns about this at the time.

The opinion of specialists in the inquiry was that when the use of nitrofurantoin exceeded six months, he should have been told about the potential risks so that he could make an informed decision about whether the benefits of continuing with it outweighed the risks.

Cooper said it was “very critical” that none of the health service providers who cared for the man, named in the decision as Mr A, ensured he understood the risks, so she considered that no single individual or service was significantly more responsible.

“Clearly, several providers failed Mr A.”

Cooper said the complaint has highlighted that some practitioners who prescribe and dispense nitrofurantoin, including those who treated this man, were not aware of the potential for serious lung damage from long-term use beyond six months.

“It has shone a light on a very important issue and prompted necessary improvements and education to reduce the chances of a similar situation in future,” she said.

The providers involved have made significant changes and improvements.

The pharmacy that dispensed the medication has asked the Pharmacy Defence Association to distribute the appropriate information to all community pharmacists. The owner said that before the incident they were not aware of the particular risk.

“When we initially discussed this as a team, I found that some of our pharmacists are aware of the rare adverse effect associated with long-term use of nitrofurantoin … Other pharmacists did not know this … All our pharmacists are now acutely aware of this risk.”

The spinal unit at Health NZ is creating an information document to be shared via the College of General Practitioners and the medical centre has conducted an audit of all patients prescribed this medication for monitoring and to ensure the side effects are reiterated to them.

The man’s GP has since made “radical changes” to prescribing practices including providing written information from the New Zealand Formulary for all long-term medications for patients and discussing the pertinent side effects with them.

In addition to the changes already made, Cooper listed follow-up recommendations including that the RCollege of General Practitioners and Te Tāhū Hauora|Health Quality & Safety Commission consider how best to further highlight awareness of the medication risks.

In a recommendation to Medsafe and the Medical Protection Society, Cooper believed a more direct approach to the urology community was worthwhile through the publication of regular updates on the risks of long-term use of nitrofurantoin.

Cooper said in concluding the investigation that she acknowledged and supported the wishes of the man’s wife in making the complaint.