Addiction, Abuse, And Misuse; Life-Threatening Respiratory Depression; Accidental Ingestion; Ultra-Rapid Metabolism Of Codeine And Other Risk Factors For Life- Threatening Respiratory Depression In Children; Neonatal Opioid Withdrawal Syndrome; Interactions With Drugs Affecting Cytochrome P450 Isoenzymes; Hepatotoxicity; And Risks From Concomitant Use With Benzodiazepines Or Other CNS Depressants; Risk Evaluation And Mitigation Strategy (Rems)

Addiction, Abuse and Misuse

• Acetaminophen and codeine phosphate tablets expose patients and other users to the risks of opioid addiction, abuse and misuse, which can lead to overdose and death. Assess each patient’s risk prior to prescribing acetaminophen and codeine phosphate tablets, and monitor all patients regularly for the development of these behaviors and conditions.
• Patients at increased risk may be prescribed opioids, but use in such patients necessitates intensive counseling about the risks and proper use along with intensive monitoring for signs of addiction, abuse, and misuse. 
• Consider prescribing naloxone for the emergency treatment of opioid overdose. 

Life-Threatening Respiratory Depression

• Serious, life-threatening, or fatal respiratory depression may occur with use of acetaminophen and codeine phosphate tablets. Monitor for respiratory depression, especially during initiation of acetaminophen and codeine phosphate tablets or following a dose increase
• Opioids can cause sleep-related breathing disorders including central sleep apnea (CSA) and sleep-related hypoxemia. Opioid use increases the risk of CSA in a dose-dependent fashion. In patients who present with CSA, consider decreasing the opioid dosage using best practices for opioid taper.

Accidental Ingestion

• Accidental ingestion of acetaminophen and codeine phosphate tablets, especially by children, can result in a fatal overdose of acetaminophen and codeine phosphate tablets

Ultra-Rapid Metabolism of Codeine and Other Risk Factors for Life- Threatening Respiratory Depression in Children 

• Life-threatening respiratory depression and death have occurred in children who received codeine. Most of the reported cases occurred following tonsillectomy and/or adenoidectomy and many of the children had evidence of being ultra-rapid metabolizers of codeine due to a CYP2D6 polymorphism
• Acetaminophen and codeine phosphate tablets are contraindicated in children younger than 12 years of age and in children younger than 18 years of age following tonsillectomy and/or adenoidectomy
• Avoid the use of acetaminophen and codeine phosphate tablets in adolescents 12 to 18 years of age who have other risk factors that may increase their sensitivity to the respiratory depressant effects of codeine. 

Neonatal Opioid Withdrawal Syndrome

• Prolonged use of acetaminophen and codeine phosphate tablets during pregnancy can result in neonatal opioid withdrawal syndrome, which may be life-threatening if not recognized and treated, and requires management according to protocols developed by neonatology experts. If opioid use is required for a prolonged period in a pregnant woman, advise the patient of the risk of neonatal opioid withdrawal syndrome and ensure that appropriate treatment will be available

Interactions with Drugs Affecting Cytochrome P450 Isoenzymes

• The effects of concomitant use or discontinuation of cytochrome P450 3A4 inducers, 3A4 inhibitors, or 2D6 inhibitors with codeine are complex. Use of cytochrome P450 3A4 inducers, 3A4 inhibitors, or 2D6 inhibitors with acetaminophen and codeine phosphate tablets requires careful consideration of the effects on the parent drug, codeine, and the active metabolite, morphine. 

Hepatotoxicity 

• Acetaminophen has been associated with cases of acute liver failure, at times resulting in liver transplant and death. Most of the cases of liver injury are associated with the use of acetaminophen at doses that exceed 4,000 milligrams per day, and often involve more than one acetaminophen-containing product

Risks from Concomitant Use with Benzodiazepines or Other CNS Depressants 

Concomitant use of opioids with benzodiazepines or other central nervous system (CNS) depressants, including alcohol, may result in profound sedation, respiratory depression, coma, and death

• Reserve concomitant prescribing of acetaminophen and codeine phosphate tablets and benzodiazepines or other CNS depressants for use in patients for whom alternative treatment options are inadequate.
• Limit dosages and durations to the minimum required.
• Follow patients for signs and symptoms of respiratory depression and sedation.