The Food and Drug Administration (FDA) published new rules on March 24, 2004, requiring content labeling (amount present per dosage unit, e.g. tablet) and warning labeling for over-the-counter (OTC) drugs that contain levels of calcium, magnesium, sodium, or potassium that might be harmful to people with certain underlying medical conditions.

FDA published these final rules in the Federal Register in order to enhance the safe use of these products by providing uniform content and warning labeling for oral OTC drug products containing levels of these substances that exceed specific thresholds. Mouth rinses, fluoride toothpastes and mouth washes are not covered by this regulation.

In addition, the agency is proposing to extend sodium content labeling requirements to OTC rectal drug products containing sodium phosphates. FDA is taking this action because people with certain medical conditions may be at risk for serious or life-threatening electrolyte imbalances when using these products.

Under the new rules, the labeling of oral OTC drugs containing sodium, calcium, magnesium, or potassium must state the amount of a particular ingredient in each dose if they contain:

* 5 milligrams (mg) or more of sodium in a single dose,
* 20 mg or more of calcium in a single dose,
* 8 mg or more of magnesium in a single dose, or
* 5 mg or more of potassium in a single dose.

The new rules also require new warnings on the label to alert people with kidney stones, decreased kidney function due to kidney disease, or people who are on sodium, calcium, magnesium, or potassium-restricted diets to consult their doctors before using products for oral ingestion that contain:

* more than 140 mg of sodium as the maximum daily dose.
* more than 3.2 grams of calcium as the maximum daily dose,
* more than 600 mg of magnesium as the maximum daily dose, or
* more than 975 mg potassium as the maximum daily dose.

"These new warnings provide an extra level of safety for people who may be especially sensitive to these commonly used OTC ingredients," said Acting FDA Commissioner Lester M. Crawford, D.V.M., Ph.D. "Although these ingredients can generally be used safely and provide benefit to many consumers, people with conditions that put them at risk of side effects need to be aware of the presence of these ingredients."

Sodium may be related to high blood pressure and is a concern for individuals with congestive heart failure. In people with kidney disease, blood levels of calcium, magnesium, and potassium can reach potentially dangerous levels due to their decreased elimination. People with kidney stones need to carefully monitor their calcium intake.

The final rules become effective on April 23, 2004. Full compliance with the regulations is required by September 25, 2005.