Following reports about life-threatening side effects and death in patients, including children, U.S. health officials warned parents and doctors about Tussionex, the prescription cough medicine.

The U.S. Food and Drug Administration issued an alert on Tuesday saying it had received reports that show doctors may be over prescribing the cough medicine made by Belgian company, UCB Inc.

“There is a real and serious risk for overdosing if this medication is not used according to the labeling,” Dr. Curtis Rosebraugh, acting director of the FDA office that regulates prescription cough medicines, said in a statement, according to Reuters.

Tussionex, sold as Tussionex Pennkinetic Extended-Release Suspension, has only been approved for adults and children over six, fact already written on its labeling. Five deaths have been reported among children under six who took Tussionex since its approval in 1987, which suggests that the warnings are not adequate, the drug being prescribed also for children fewer than 6.

Moreover, it was reported that Tussionex was improperly prescribed for children at a dosing frequency of less than every 12 hours. The FDA advised that patients unable to control cough with a dose every 12 hours should consult physicians before increasing the dose frequency.

Tussionex contains hydrocodone, a narcotic ingredient, and the antihistamine chlorpheniramine. Hydrocodone is habit-forming and can lead to physical and psychological addiction. Symptoms of hydrocodone overdose include trouble breathing; slow or shallow breathing; slow heartbeat; severe sleepiness; cold, clammy skin; trouble walking or talking; or feeling faint, dizzy, or confused. An overdose of hydrocodone can be fatal.

UCB will update the Tussionex label to address the concerns, the FDA said. "The FDA's alert is fully in line with our efforts to make sure this product is properly used," a representative for UCB told Reuters,

Tussionex is not the only cough medicine raising concerns among health officials. In January, the FDA issued a warning that such medicines should not be administered to children under two. . The FDA is still reviewing these medications for use in older children, and could provide further guidance in the coming months.