December 11, 2013
High Sodium Drug Formulations Could Raise Patients’ Cardiovascular Risks

Dundee, Scotland—Patients who take effervescent, dispersible, or soluble drugs—including certain formulations of aspirin or acetaminophen—could be putting themselves at risk by exceeding daily-recommended limits for sodium, according to a new study.

In an article in the British Medical Journal, researchers from the University of Dundee and University College London are sounding warnings “about the potential dangers of high sodium intake from prescribed medicines.” Authors of the study suggested that sodium-containing formulations “should be prescribed with caution only if the perceived benefits outweigh the risks.”

They also call for labeling of the sodium content of medications, similar to requirements for food products. Many of the effervescent, dispersible or soluble drugs contain sodium bicarbonate, the authors note.

For the study conducted between 1987 and 2010, researchers 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. Effervescent formulations of paracetamol 500 mg (sold as acetaminophen in the U.S.) were the most widely prescribed of the drugs among the study sample, according to the report, and can contain 18.6 mmol and 16.9 mmol of sodium in each tablet. The study only looked at prescription drugs and did not take into account OTC drugs that could have high sodium levels.

With more than 1.2 million UK patients tracked for an average of 7.23 years, 61,000 incident cardiovascular events occurred. Median time from date of first prescription to first occurrence of cardiovascular events was slightly less than 4 years.

Patients using the sodium-containing effervescent, dispersible, and soluble medications had a 16% increased risk of a heart attack, stroke, or vascular death and were seven times more likely to develop high blood pressure, compared with other patients taking the nonsodium versions of those exact medications, according to the results. Overall death rates were 28% higher in the group using medications with higher sodium levels.

While controversy continues over whether dietary sodium directly affects cardiovascular risks, the authors maintain that their findings “are potentially of public health importance.”

“Prescription of these sodium-containing formulations should be done with caution, and patients prescribed them should be closely monitored for the emergence of hypertension,” they conclude.

U.S. Pharmacist Social Connect