A new study revealed that the use of codeine, which has been prescribed to pediatric patients as an analgesic and antitussive agent, could potentially result to life-threatening respiratory complications in children.

Codeine is an opioid pain medication used to treat mild to moderately severe pain. As a prodrug, codeine has a little inherent pharmacologic activity and must be metabolized in the liver into morphine.

The study, published in the journal Pediatrics, showed that the genetic variability of the enzyme CYP2D6, which is responsible for converting codeine to morphine, could influence the patient's response to codeine use from no effect to high sensitivity.

One of the most adverse effects associated with codeine use is fatal respiratory depression. About 64 cases of severe respiratory depression that occurred in children being treated with codeine were reported between 1965 and 2015. Additionally, the Foods and Drugs Administration also recorded 24 codeine-related deaths, in which 21 are children younger than 12 years of age, in the same period.

According to the report from Clinical Advisor, patients with undiagnosed sleep apnea may also be at risk of the adverse effects of codeine due to the prevalence of opioid sensitivity in this population. People with untreated or uncontrolled asthma, bowel obstruction or frequent episodes of hyperventilation are advised not to take the medicine.

Due to the differing effects of codeine, various organization and regulatory bodies, including the World Health Organization, European Medicines Agency and US Food and Drugs Administration, are considering a declaration of a contraindication for the use of codeine for children as either an analgesic or an antitussive.

In the United States, the FDA added a "black box warning", the strongest warning the FDA requires for drugs that carries life-threatening risk, in the label of codeine and codeine-containing preparations. The warning advises health care professionals "to prescribe an alternative analgesic [to codeine] for postoperative pain control in children undergoing tonsillectomy and/or adenoidectomy."

The researchers of the new study noted that additional clinical research is needed to better understand the risk both opioid and non-opioid alternatives use to treat acute and chronic pain.