Adverse Side Effects of Tylenol 3

Tylenol 3 is a brand name of one available combination pain reliever containing the medications codeine and acetaminophen. Each Tylenol 3 tablet contains 325mg acetaminophen and 30mg codeine and is often prescribed at two tablets per dose. Codeine is a narcotic, and as with all narcotic-type combination pain medications, the side effects can range from mild to serious.

Gastrointestinal Distress

Stomach complaints are some of the most common side effects of many medications including opiate-type pain relievers such as Tylenol 3. Most patients who have stomach problems will experience mild to moderate nausea, and some may experience vomiting as well. Taking the medication with food may reduce these symptoms. In most cases, nausea will lessen as you become used to the medication. Patients who take the medication for a long period of time may experience constipation, which may require treatment with a laxative.


Dizziness and lightheadedness are common side effects of Tylenol 3. These effects are often relieved or lessened in severity by lying down. In most cases, you will become used to the medication and these effects will subside. Because Tylenol 3 contains the opiate-type medication codeine, drowsiness is also reported as a common side effect. More severe changes in mental status, particularly fainting, inability to wake or slowed, shallow breathing may indicate overdose and warrant emergency medical treatment.

Impaired Thinking

Changes in cognitive function such as impaired or foggy thinking and confusion are commonly experienced by patients taking Tylenol 3. Other patients report symptoms of irritability or anxiety. Most side effects affecting mental functioning will subside over time, but some long-term users of narcotic medications may experience depression. Report serious changes in cognitive or social functioning to your physician.

Allergic Reaction

The codeine in Tylenol 3 may cause an allergic reaction in some patients. Mild symptoms of allergic reaction may include itching or rash, while more severe reactions include hives, swelling of the tongue or throat and difficulty breathing. Symptoms of allergic reaction will likely warrant discontinuation of the medication. Report any allergic side effects that occur to a physician immediately. Severe allergies have led to death in some patients.

Liver Toxicity

Acetaminophen is widely known to cause liver damage when used in high doses or for long periods of time. Acetaminophen use should be limited to four grams daily to preserve liver functioning, which means a maximum of 12 tablets per day according to Tylenol 3 dosing information.

Potential for Abuse

All opiate-type medications including Tylenol 3 have a potential risk for abuse and addiction. Pain medications should be taken according to instructions, exactly as prescribed for this reason. Even when taken according to instruction, some patients may develop physical dependence on the medication with long term use. Symptoms of withdrawal, including flu-like symptoms, diarrhea, sweating and anxiety, may occur when the medication is discontinued. Symptoms of overdose include extreme sedation and difficulty breathing. Symptoms of withdrawal or overdose should be reported to a physician immediately.

About this Author

Melissa Lind holds a Bachelor of Science degree from the University of Texas College of Pharmacy. She has over 20 years’ experience as a health care professional, including pharmacy practice as a registered pharmacist, clinical research management and community college instruction in pharmacology and health topics. Lind has been a freelance writer and independent content provider for five years.