Prescription strength Prilosec, Nexium and similar stomach acid reducing drugs, known as proton pump inhibitors (PPIs), will have to carry new label warnings alerting consumers to a risk of low magnesium levels, federal drug regulators announced Wednesday.
In a Drug Safety Communication, the FDA says that it has determined that long-term use of proton pump inhibitors (PPIs), like Nexium and Prilosec, may cause low serum magnesium levels; a condition known as hypomagnesemia.
Over-the-counter versions of the drugs are not affected by the warning because they are marketed at low doses and only intended for 14-day treatments. FDA officials believe there is little risk of hypomagnesemia with OTC PPIs.
Hypomagnesemia can cause serious side effects, including muscle spasms, irregular heartbeats, and convulsions. According to the FDA, the condition cannot be simply treated through the use of magnesium supplements and in most cases the patient had to be taken off PPIs for their magnesium levels to return to normal.
The FDA found more than 50 cases of hypomagnesemia that were likely caused by heartburn drug side effects in medical literature and through adverse events reported to the agency. While in some cases it appeared in adults who had only been taking drugs like Prilosec and Nexium for just three months, in most cases it appeared after about a year of use.
Patients taking PPIs should seek immediate medical attention if they experience abnormal heart rates or rhythms, palpitations, muscle spasms, tremors or convulsions. Children may demonstrate signs of hypomagnesemia as fatigue, upset stomach, dizziness or lightheadedness. Patients on Digitek or a diuretic should also inform their doctors when being prescribed a PPI, because these drugs also can cause low magnesium levels.
Healthcare professionals should check the magnesium levels of patients before prescribing a prescription PPI and should periodically check their magnesium levels. They should also educate patients taking PPIs on the signs of hypomagnesemia.
The prescription drugs pull in about $14 billion in U.S. sales each year, and many are prescribed for indigestion and heart burn, although with the exception of Prilosec, they are only approved for treatment of ulcers, acid reflux disease and erosive esophagitis. There were about 119 million prescriptions for proton pump inhibitors in the U.S. last year. Some medical experts estimate that as many as 69% of proton pump inhibitor prescriptions were written for “off-label” uses, which have not been approved as safe and effective by the FDA.