A very serious allergic reaction to Tylenol Extra Strength Back Pain Plus Muscle Relaxant is rare. However, seek medical help immediately if you experience symptoms of a serious allergic reaction, such as rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, or trouble breathing. This is not a complete list of possible side effects. If you notice other effects not listed above while using extra strength tylenol for back pain relief, contact your doctor or pharmacist promptly.
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