The UK medicines regulator has called for GPs to check the magnesium levels of all patients on proton-pump inhibitors, in advice experts have warned represents a ‘massive undertaking' for primary care.
The Medicines and Healthcare products Regulatory Agency said magnesium levels should be tested on initiation and ‘periodically' thereafter, following reports to regulatory authorities in Europe that PPIs may cause hypomagnesaemia, with most cases occurring a year after treatment.
The MHRA said the symptoms of hypomagnesaemia could be easily overlooked and urged GPs to ensure they tested patients on prolonged treatment, and anyone that might be at greater risk. They also urged GPs to ‘take account' of any PPIs that were obtained over the counter.
The advice – in the MHRA's Drug Safety Bulletin for April – says: ‘Severe hypomagnesaemia has been reported infrequently in patients treated with PPIs, although the exact incidence is unknown.'
‘For patients expected to be on prolonged treatment, and especially for those who take PPIs with digoxin or drugs that may cause hypomagnesaemia (e.g. diuretics), healthcare professionals should consider measuring magnesium levels before starting PPI treatment and repeat measurements periodically during treatment.'
But Dr John O'Malley, a hospital practitioner in gastroenterology in the Wirral and secretary of the Primary Care Gastroenterology Society, warned the proposal would have a major workload impact on GP practices.
‘This is a big burden for primary care to take on and I don't think the evidence is there to measure magnesium levels on everybody,' he said.
‘It is underestimating what a massive undertaking this will be. The average practice will have hundreds of patients on PPIs.
‘If you are asking for a couple of hundred people to have their magnesium levels done once a year – it is crazy. This is not a routine investigation.'