<p>Acetaminophen (paracetamol), also commonly known as <em>Tylenol</em>, is the most commonly taken analgesic worldwide and is recommended as first-line therapy in pain conditions by the World Health Organization (WHO).<sup class="text-reference-group"><a class="reference-popover-link" data-content="Ennis ZN, Dideriksen D, Vaegter HB, Handberg G, Pottegard A: Acetaminophen for Chronic Pain: A Systematic Review on Efficacy. Basic Clin Pharmacol Toxicol. 2016 Mar;118(3):184-9. doi: 10.1111/bcpt.12527. Epub 2015 Dec 28. (PubMed ID 26572078)" href="#reference-A176318">10</a></sup> It is also used for its antipyretic effects, helping to reduce fever.<sup class="text-reference-group"><a class="reference-popover-link" data-content="Acetaminophen monograph, suppository" href="#reference-F4124">23</a></sup> This drug was initially approved by the U.S. FDA in 1951 and is available in a variety of forms including syrup form, regular tablets, effervescent tablets, injection, suppository, and other forms.<sup class="text-reference-group"><a class="reference-popover-link" data-content="Acetaminophen tablet, DailyMed" href="#reference-L5756">15</a>,<a class="reference-popover-link" data-content="Acetaminophen effervescent tablets, Cleveland Clinic" href="#reference-L5774">16</a>,<a class="reference-popover-link" data-content="Acetaminophen monograph, suppository" href="#reference-F4124">23</a>,<a class="reference-popover-link" data-content="Official drug label" href="#label-reference">Label</a></sup></p><p>Acetaminophen is often found combined with other drugs in more than 600 over the counter (OTC) allergy medications, cold medications, sleep medications, pain relievers, and other products.<sup class="text-reference-group"><a class="reference-popover-link" data-content="FDA consumer health information: Acetaminophen" href="#reference-L5783">19</a></sup> Confusion about dosing of this drug may be caused by the availability of different formulas, strengths, and dosage instructions for children of different ages.<sup class="text-reference-group"><a class="reference-popover-link" data-content="FDA consumer health information: Acetaminophen" href="#reference-L5783">19</a></sup> Due to the possibility of fatal overdose and liver failure associated with the incorrect use of acetaminophen, it is important to follow current and available national and manufacturer dosing guidelines while this drug is taken or prescribed.<sup class="text-reference-group"><a class="reference-popover-link" data-content="FDA : Acetaminophen Information" href="#reference-L5786">20</a>,<a class="reference-popover-link" data-content="Using Acetaminophen and Nonsteroidal Anti-inflammatory Drugs Safely" href="#reference-L5789">21</a>,<a class="reference-popover-link" data-content="Official drug label" href="#label-reference">Label</a></sup></p>