From the Guidelines
Yes, codeine is an opioid. It is a naturally occurring alkaloid found in the opium poppy plant and belongs to the class of medications known as opioid analgesics. Codeine works by binding to opioid receptors in the brain and spinal cord, changing how the body senses pain and producing pain relief. It is commonly prescribed for mild to moderate pain and as a cough suppressant. Codeine is considered less potent than other opioids like morphine or oxycodone, but it still carries risks of dependence, addiction, and respiratory depression, especially at higher doses. In the body, some codeine is converted to morphine by liver enzymes, which contributes to its pain-relieving effects. Due to its opioid classification, codeine is subject to controlled substance regulations in most countries, though the specific scheduling and availability vary by jurisdiction. Patients should be aware that even though it may be perceived as "milder" than other opioids, codeine still requires careful use according to prescribed guidelines.
Key Points
- Codeine is a naturally occurring opioid analgesic
- It is used for mild to moderate pain and as a cough suppressant
- Codeine carries risks of dependence, addiction, and respiratory depression
- It is subject to controlled substance regulations in most countries
- Patients should use codeine carefully and according to prescribed guidelines
Evidence
The evidence from various studies, including those published in the Chest 1, Annals of Emergency Medicine 1, and Journal of Clinical Oncology 1, supports the fact that codeine is an opioid and should be used with caution. The American Society of Clinical Oncology clinical practice guideline 1 also recommends careful use of opioids, including codeine, in cancer patients. Additionally, the Mayo Clinic Proceedings article 1 provides guidance on the preoperative management of opioid and nonopioid analgesics, including codeine.
Recommendations
Codeine should be used with caution and only as prescribed by a healthcare provider. Patients should be aware of the risks associated with codeine use and follow the prescribed dosage and administration guidelines carefully. Healthcare providers should also monitor patients closely for signs of dependence, addiction, and respiratory depression, and adjust the treatment plan as needed.
From the FDA Drug Label
Drug Facts Active Ingredients Purpose (in each teaspoonful (5 mL)) Codeine Phosphate USP 10 mg ................... Antitussive
- Codeine is listed as an active ingredient in the drug label 2
- The drug label does not explicitly state that codeine is an opioid, but codeine phosphate is known to be an opioid in medical literature, however, this information is not present in the provided drug labels. The FDA drug label does not answer the question.
From the Research
Definition and Classification of Codeine
- Codeine is a centrally acting narcotic opioid approved for use as an antitussive, a prodrug that is bioactivated by CYP2D6 into morphine in the liver 3.
- The opioid effects of codeine are related to plasma morphine concentrations 3.
- Codeine is considered a "weak" opioid analgesic, often used to treat severe pain, or when paracetamol or a nonsteroidal anti-inflammatory drug (NSAID) proves inadequate 4.
Comparison with Other Opioids
- Codeine has a similar risk profile to morphine, with the potential for abuse and dependence 5, 4.
- The potency of codeine is strongly influenced by the cytochrome P450 isoenzyme CYP2D6 genotype, which varies widely from one person to another 4.
- Codeine can have the same dose-dependent adverse effects as morphine, including respiratory depression 4.
Clinical Use and Efficacy
- Codeine is widely used as an analgesic, antidiarrhoeal, and antitussive agent, but its efficacy and safety have been questioned 5, 3, 6.
- Codeine has been shown to be more effective against cancer pain than placebo, but with increased risk of nausea, vomiting, and constipation 6.
- The use of codeine as an antitussive in acute or chronic cough is not supported by reliable clinical evidence 5.