Many formulations of common medications contain high levels of sodium, and a new study has found that people who take those medications are 22 percent more likely to suffer a non-fatal stroke and 28 percent more likely to die of any cause than people who take the same medications in formulations that do not contain sodium.
Among the patients in the study who took medications containing sodium, the median daily sodium dose from those medicines alone was 106.8 millimoles a day — higher than the recommended daily maximum dietary intake of 104 millimoles a day.
The newest study on sodium in medicines was published Tuesday in the British Medical Journal.
Medicines that come in powdered, effervescent or soluble formulations tend to be particularly high in sodium, and researchers in London and Dundee, Scotland, collected a list of 24 drugs that were available in such formulations. Among them were effervescent or soluble versions of the pain relievers acetaminophen and aspirin; metoclopramide, taken to soothe stomach ulcers and gastrointestinal reflux, and calcium and zinc supplements.
They then combed through a computerized database of British medical records to follow 1,292,337 patients for an average of just over seven years. Their aim was to detect whether people who suffered cardiovascular "events" were more or less likely than those who did not to have taken medications high in sodium content.
In that time, 61,072 patients suffered a non-fatal stroke, heart attack or death attributable to vascular disease.
The researchers drew from the medical records to match those patients with control subjects similar in age, sex and health status. Then, they looked for a recent history of taking sodium-containing medications in both groups.
Those who suffered a stroke, a heart attack or vascular death were, on average, 16 percent more likely to have taken high-sodium formulations of drugs than those who did not suffer such an outcome.
The authors of the study wrote that the public "should be warned about the potential dangers of high sodium intake from prescribed medicines." They recommended that sodium-containing formulations should only rarely be prescribed when formulations without sodium exist.
They also called for the sodium content of medicines to be clearly labeled the same way that foods are labeled. That would be a change, since pharmaceutical manufacturers are not currently required to reveal the sodium content of their formulations.
High dietary sodium intake has been linked to hypertension and can reduce the effectiveness of medication for high blood pressure.