Safety and efficacy of the combination acetaminophen-codeine in the treatment of pain of different origin.

BACKGROUND: Pain is the most common reason people see doctors in developed Countries and a very common cause of access in Emergency Department (ED). The combination acetaminophen/codeine represents the standard medication in the second step of the WHO analgesic scale and codeine is one of the most commonly used opioid analgesic for a variety of pain conditions. However, many aspects related to safety and efficacy are still undefined. AIM: To summarize and review the results of the most relevant studies on the efficacy and safety profile of acetaminophen/codeine combination in the treatment of pain of different origin. MATERIALS AND METHODS: We performed a literature search to identify and evaluate all relevant english-language randomized controlled trials (RCTs), meta-analyses and reviews about the codeine plus paracetamol combination in the treament of pain from any source. RESULTS: Acetaminophen/codeine combination is effective in the treatment of moderate to severe pain in all setting analyzed in this study, which include headache, postoperative, osteoarticular and post-traumatic. The best results in terms of safety and efficacy have been obtained in postoperative pain. Efficacy of acetaminophen/codeine combination is not inferior to NSAIDs. CONCLUSIONS: Acetaminophen/codeine combination is effective in the treatment of pain, through a synergistic action of the two molecules, and is not inferior to NSAIDs. Side effects of acetaminophen/codeine are usually minor, differently from NSAIDs, which may induce some potentially lifethreatening conditions.