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The recall of an infant pain reliever has been expanded over worries that the over-the-counter medication may contain dangerously high concentrations of the drug.

On Thursday, the drug maker Tris-Pharma said that additional lots of Infants' Ibuprofen Concentrated Oral Suspension, USP (NSAID) 50 mg per 1.25 mL — sold in 0.5 oz. bottles at Wal-Mart, CVS Pharmacy and Family Dollar Services — may have higher concentrations of ibuprofen than what’s on the label.

Tris Pharma has expanded their nationwide recall of ibuprofen oral suspension drops. Tris Pharma, Inc.

Routine tests found that some units contained 10 percent more ibuprofen than specified levels. Normal levels per bottle are 50 mg of ibuprofen per 1.25ml.

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“Studies have shown that safety issues or toxicity is generally accepted to be a concern in infants at doses in excess of 700 percent of the recommended dose. To date, no serious adverse events have been reported related to this recall,” the company said.

The FDA, which monitors drugs in the U.S. said infants already susceptible to the adverse effects of ibuprofen may be at a slightly higher risk if they receive medication from an impacted bottle, in a statement issued Wednesday.

The higher concentration could cause nausea, vomiting, diarrhea, headache, stomach bleeding, and kidney damage, according to Tris-Pharma.

The original recall last November was for three batches of of the ibuprofen drops. The new recall includes three more batches.

Recalled batches

Walmart sells the recalled product under the “Equate” label and the National Drug Code (NDC) 49035-125-23; the products being withdrawn have the lot numbers 00717005A, 00717009A, 00717015A and 00717024A on their label.

CVS offers it under the “CVS Health” label, with the recalled products bearing the NCD number 59779-925-23 and the lot numbers 4718, 00717006A and 00717024A.

At Family Dollar, it's sold under the “Family Wellness” label with the NCD 55319-250-23 and lot number 00717024A.

For more information about the recall, consumers can call Tris-Pharma at 732-940-0358, Monday through Friday, 8 a.m. Eastern- 5 p.m. Pacific.