<qa>  What is the maximum dose of acetaminophen in 24 hours?11. If patient complains of headache, one or two tablets of 500 mg acetaminophen will be given by mouth every 4 hours as needed. One tablet will be given if the patient reports a value of 0-3 on the pain scale, and two tablets will be given if the patient reports a value of 4 or greater on the pain scale. The maximum dose of acetaminophen is 4g in 24 hours. 