The U.S. Food and Drug Administration has issued a warning that children younger than 10 years old who accidentally ingest Tessalon liquid cough capsules may be at risk for serious side effects or death.

The agency said that Tessalon, also known as benzonatate, is approved to treat cough symptoms in patients 10 and older but that its safety for younger children has not been determined.

The FDA said that it has received seven reports since 1982 of children accidentally ingesting the drug, including five cases in which children two or younger died. it also reported that overdoses, which can occur with children 2 and younger after the ingestion of a single capsule, resulted in cardiac arrest, coma and convulsions.

Agency officials expressed concern that Tessalon — which comes in round, liquid-filled gelatin capsules — may attract children because it looks like candy. They are urging parents to keep the drug in child-proof containers.

Tessalon is sold by Forest Pharmaceuticals inc., but the product has been on the market for decades and several generic companies make versions, the Associated Press reports.