Serious, life-threatening, or fatal respiratory depression may occur with use of acetaminophen and codeine phosphate tablets, especially during initiation or following a dosage increase. To reduce the risk of respiratory depression, proper dosing and titration of Acetaminophen and codeine phosphate tablets are essential [see Warnings]. Get clear safety guidance for APAP w/Codeine, including warnings, precautions, when to seek medical assistance, and how to use it correctly. APAP codeine is a prescription pain reliever that combines two drugs: acetaminophen (abbreviated APAP, from its chemical name N-acetyl-para-aminophenol) and codeine phosphate, a mild opioid. The combination is often sold under the brand name Tylenol 3, though generic versions are widely prescribed. It contains an opioid pain reliever (codeine) and a non-opioid pain reliever (acetaminophen). Codeine works in the brain to change how your body feels and responds to pain. Overview: Acetaminophen/codeine is used to treat certain types of pain. It reduces pain signals and changes how your body feels pain. Common side effects include constipation and feeling sleepy. What is acetaminophen and codeine? Acetaminophen and codeine is a combination medicine used to relieve moderate to severe pain. Acetaminophen and codeine may also be used for purposes not listed in this medication guide. Acetaminophen and codeine combination oral solution or tablet can cause serious unwanted effects or fatal overdose if taken by children, pets, or adults who are not used to strong narcotic pain medicines. Tylenol with Codeine (acetaminophen / codeine), also known as Tylenol 3, is a combination opioid medication. It's used for mild-to-moderate pain when other non-opioid therapies haven't worked well enough. 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. The combination of acetaminophen and codeine may cause serious or life-threatening breathing problems, especially during the first 24 to 72 hours of your treatment and any time your dose is increased.