A new study has highlighted the increased risk of a heart attack due to the high salt levels found in many medicines.
In an analysis published by the BMJ, researchers at the University of Dundee and University College London found that taking the maximum daily dose of some medicines would exceed the recommended daily limits for sodium, without any additional food intake.
Researchers at the University of Dundee and University College London found that taking the maximum daily dose of some medicines would exceed the recommended daily limits for sodium, without any additional dietary intake. Many commonly prescribed drugs have salt added to improve absorption into the body.
The team compared the risk of non-fatal heart attacks and stoke, or vascular death in patients taking sodium-containing effervescent, dispersible and soluble medications with those taking non-salt versions of the same drugs between 1987 and 2010. The treatments included paracetamol, aspirin, ibuprofen, vitamin C, calcium, zinc and metoclopramide for migraines.
Over 1.2 million UK patients were tracked for an average of just over seven years. During this time, over 61,000 incident cardiovascular events occurred. Factors likely to affect the results, such as body mass index, smoking, alcohol intake, history of various chronic illnesses and use of certain other medications, were taken into account.
16% increased risk of heart attack
The researchers found that patients taking the sodium-containing drugs had a 16% increased risk of a heart attack, stroke or vascular death and were also seven times more likely to develop high blood pressure. Overall death rates were also 28% higher in this group, largely driven by an increased risk of hypertension and stroke.
The authors acknowledge that there is still some controversy regarding the relation between dietary sodium and cardiovascular events, but say their findings "are potentially of public health importance." They add that the public "should be warned about the potential dangers of high sodium intake from prescribed medicines" and that sodium-containing formulations "should be prescribed with caution only if the perceived benefits outweigh the risks".
They also call for the sodium content of medicines to be clearly labelled in same way as foods, adding that prescription of these formulations "should be done with caution and patients prescribed them should be closely monitored for the emergence of hypertension".
Commenting on the analysis, Ana Nicholls, healthcare analyst at The Economist Intelligence Unit, said the large-scale study "will lend weight to arguments against the widespread use of aspirin by people who aren't at risk of heart attacks or strokes". She added that "it is ironic that some of the well-known benefits of the drug for preventing heart attacks could be undermined by the sodium put in to make it easier to absorb".
Ms Nicholls went on to say "it's also worrying that the information about sodium content was so difficult to come by - even for researchers, let alone the general public". Regulators do keep databases of inactive ingredients, "and they have to be shown to be safe," she added, "but there have been several cases where they have been linked to side-effects [and] there may be a case for putting more information in the labelling".