OTC domperidone will be missed

The antiemetic domperidone’s reclassification shows the importance of pharmacovigilance, but the loss of such a useful over-the-counter medicine ought to have been better communicated to community pharmacies.

On 3 September 2014, community pharmacists were given 48 hours to remove over-the-counter (OTC) domperidone products from their shelves over concerns about cardiac safety. The UK’s Medicines and Healthcare products Regulatory Agency had stripped the product of its status as a pharmacy medicine and the drug is now only available with a prescription.

The injectable form of domperidone was withdrawn in 1985 because of cardiac side effects. But the oral form had long been considered to be well tolerated with minimal toxicity — which is why it was switched from prescription to pharmacy medicine in 1998 for the relief of post-prandial symptoms of fullness, nausea, bloating and belching, occasionally accompanied by epigastric discomfort and heartburn.

The 10mg oral domperidone product had its OTC licence extended in 2010 to include the relief of nausea and vomiting lasting less than 48 hours.

In consulting on the licence extension, the MHRA acknowledged that there are few treatments available for purchase in pharmacies to manage nausea and vomiting, leaving pharmacists frequently having to refer patients to their doctor. The medicines regulator said that pharmacists are well placed to manage such symptoms, which typically resolve within 48 hours.

But new concerns about cardiac safety began to emerge within a year of that licencing decision. Manufacturers McNeil and Sanofi made an announcement in 2011 to draw attention to epidemiological study findings, and product information was updated accordingly.

A review of domperidone by the European Medicines Agency began in 2013 at the request of the Belgian medicines authority. This confirmed a small increased risk of serious ventricular arrhythmia or sudden cardiac death — particularly among people older than 60 years of age, people taking oral domperidone doses of more than 30mg per day, and those taking interacting medicines. The OTC licence was restricted to the treatment of nausea and vomiting in May 2014.

It could be argued that pharmacists might have anticipated the subsequent reclassification. But they ought to have received more warning so counter staff could be given adequate training on what advice they can now give people who turn up with a stomach bug, for instance.

It is a pity to see domperidone return to prescription-only after 16 years, because there is no similar OTC option available. The MHRA believes that pharmacists would not be able to assess quickly and accurately which patients are at risk of cardiac side effects. So doctors will now have to deal with many patients who might have been successfully treated by their pharmacist.

Much like the reclassification of tramadol as a controlled drug in June 2014, the return of domperidone to prescription might jar with pharmacists. But it affirms the importance of monitoring the real-world use of medicines, and challenges our assumptions about the safety of commonly used products.

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Citation
The Pharmaceutical Journal, PJ, 27 September 2014, Vol 293, No 7829;293(7829):DOI:10.1211/PJ.2014.20066612