Acetaminophen (paracetamol): Properties, clinical uses, and adverse effects

Acetaminophen (paracetemol) is a non-opioid analgesic and antipyretic widely used for a large variety of mild to moderate pain conditions in a large variety of patient populations. In addition to over-the-counter oral and rectal formulations, there is a more-recently approved intravenous formulation. Some of the common uses of acetaminophen include the pain associated with headaches, muscle aches, menstrual periods, colds and sore throats, toothaches, backaches, osteoarthritis, and the reduction of fever. In addition to its use as a single agent, acetaminophen is also commonly used in fixed-ratio combinations with other analgesics in order to enhance pharmacokinetic or pharmacodynamic characteristics. In some cases the combination can result in a synergistic analgesic effect. The exact mechanism responsible for acetaminophen's analgesic effect is not known despite its long history of use, but it appears to involve actions on both the central and peripheral nervous systems. The safety profile of acetaminophen is considered to be very good and most side effects are mild and transient at recommended doses. However, severe hepatic toxicity has been associated with prolonged exposure, in combination with alcohol, or in cases of intentional or accidental overdose. Accidental overdose is a particular current concern because of the prevalence of acetaminophen in multiple over-the-counter products and the cumulative effect of inadvertent ingestion of an excess amount in aggregate. Overall, when used safely and properly, acetaminophen is a very good mild to moderate pain reliever for the general consumer and postoperative patient. It is particularly useful in situations where a nonopioid analgesic with good GI tolerability is desirable.