Some soluble over-the-counter pain medication may actually be posing a health risk with its high content of salt.

According to BBC News, new research shows that medications with at least 23 mg of sodium can heighten a patient's risk of heart attack and stroke. The new BMJ study examined outcomes of 1.2 million patients in the U.K.

Such medications come with a warning for patients. If the patient is on a low-sodium diet, the leaflet advises them to take the medication's salt content into account. The study found that, compared with patients who took the medication without salt, people's risk of heart attack and stroke rose with the effervescent or soluble meds.

The root of the problem, study lead researcher Dr. Jacob George said, is salt commonly leads to high blood pressure and hypertension.

"We know that high salt causes hypertension and that hypertension leads to stroke," said George, of Dundee University.

Effervescent drugs may be better known as the medications that "fizzle," because they contain an ingredient known as bicarbonate. This makes the medication dissolve with a "fizzing" sound, but it often comes with a dose of sodium.

For the study, the researchers looked at 24 of these drugs, which ranged from common painkillers like aspirin to various other types of supplements. George said many more patients bought these medications from chemists and without a prescription.

George recommended drug companies cut their salt content and warned patients to be careful of what they are taking.

A spokeswoman for the Medicines and Healthcare products Regulatory Agency (MHRA) said they are taking the study's findings into consideration.

"We will carefully review the findings of this new research," said the spokeswoman. "We recommend that people with questions about their salt intake should read the patient information leaflet and speak to their GP."

Blood Pressure U.K.'s professor Gareth Beevers said the warnings against too much salt consumption needs to be plenty obvious for patients.

"Without clear labelling on these products, it is impossible to know how much additional sodium you would be eating, so it is shocking to find you could be having more than your daily maximum from medicines alone," he said. "Eating too much sodium - in any form - puts up our blood pressure, which puts you at increased risk of strokes and heart attacks, the biggest killers in the world."