Most people know that any drug, over-the-counter or prescription, has potential side effects, and can cause harm. But until last month, their cost-benefit consideration usually didn’t concern their sodium levels.
A study in BMJ (British Medical Journal) showed that the maximum daily dose of some medicines would exceed recommended daily limits for sodium irrespective of the salt a patient consumes from meals.
The researchers concluded that the salt content of medicine should be labeled just as it is in food.
In a news release, the journal authors said 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.”
Their concern is that excess salt is not good for the heart. A lot of medicines contain sodium because it aids absorption. The effect of this digestive assist, however, hasn’t been studied for its role in cardiovascular events. But most people get too much salt anyway, and additional amounts can’t be good.
The American Heart Association says that 9 in 10 Americans eat too much sodium. The daily recommendation is no more than 1,500 milligrams, but the average person consumes more than twice that amount.
In some people, excess sodium can lead to high blood pressure, increased risk of stroke, heart failure, osteoporosis (bone loss), stomach cancer, kidney disease, kidney stones, enlarged heart muscle and headaches.
Researchers from the University of Dundee and University College London compared the risk of cardiovascular events (nonfatal heart attack, nonfatal stoke or vascular death) in patients taking sodium-containing effervescent, dispersible and soluble medications with those taking nonsodium versions of the same drugs.
Many effervescent tablets use sodium bicarbonate to make them fizz; other medications use sodium compounds to aid their dispersal, or to help them dissolve in water. Common drugs such as Alka Seltzer and Gaviscon, for example, contain sodium.
“These drugs are also available over the counter, they can be picked up in the supermarket,” the study’s lead researcher told Britain’s Guardian newspaper. “We have no control over how many millions of people are buying these drugs. The ones we looked at were prescribed by GPs [general practitioners], but there’s a potentially much larger problem with these drugs being bought over the counter and in supermarkets.”
More than 1.2 million patients in the United Kingdom were tracked for an average of more than seven years. Complicating factors, such as body mass index, smoking, alcohol intake, history of various chronic illnesses and use of certain other medications, were taken into account. More than 61,000 incident cardiovascular events occurred.
Patients taking the sodium-containing medications had a 16% increased risk of a heart attack, stroke or vascular death compared with other those taking the nonsodium versions of the same meds.
The sodium-takers also were seven times likelier to develop high blood pressure. Their overall death rates were 28% higher, largely because of an increased risk of hypertension and stroke.
The relationship between dietary sodium and heart trouble is not a slam-dunk for every person – scientists are not unanimous in their appraisal of salt’s role in cardiac events, which the researchers acknowledged. Their point is that the sodium content of medicine is “potentially of public health importance.”
They advise doctors prescribing medicine containing sodium, and patients taking it on their own, to do so with caution, and to monitor for hypertension.