«Paracetamol, also known as acetaminophen and APAP, is a medicine used to treat pain and fever.^[1] It is typically used for mild to moderate pain relief.^[1] Evidence for its use to relieve fever in children is mixed.^[11][12] It is often sold in combination with other medications, such as in many cold medications.^[1] In combination with opioid pain medication, paracetamol is also used for severe pain such as cancer pain and pain after surgery.^[13] It is typically used either by mouth or rectally, but is also available intravenously.^[1][14] Effects last between 2 and 4 hours.^[14]

Paracetamol is generally safe at recommended doses.^[15] The recommended maximum daily dose for an adult is 3 or 4 grams.^[16][17] Higher doses may lead to toxicity, including liver failure.^[1] Serious skin rashes may rarely occur.^[1] It appears to be safe during pregnancy and when breastfeeding.^[1] In those with liver disease, it may still be used, but in lower doses.^[18] It is classified as a mild analgesic.^[14] It does not have significant anti-inflammatory activity and how it works is not entirely clear.^[19]

Paracetamol was first made in 1877.^[20] It is the most commonly used medication for pain and fever in both the United States and Europe.^[21] It is on the World Health Organization's List of Essential Medicines, the most effective and safe medicines needed in a health system.^[22] Paracetamol is available as a generic medication with trade names including Tylenol and Panadol, among others.^[23] The wholesale price in the developing world is less than US$ 0.01 per dose.^[24] In the United States, it costs about US$0.04 per dose.^[25]

Paracetamol is used for reducing fever in people of all age.^[26] The World Health Organization recommends that paracetamol be used to treat fever in children only if their temperature is higher than 38.5 °C (101.3 °F).^[27] The efficacy of paracetamol by itself in children with fevers has been question^[28] and a meta-analysis showed that it is less effective than ibuprofen.^[29] Paracetamol does not have significant anti-inflammatory effects.

Paracetamol is used for the relief of mild to moderate pain.^[1] The use of the intravenous form for short-term pain in people in the emergency department is supported by limited evidence.^[30]

The American College of Rheumatology recommends paracetamol as one of several treatment options for people with arthritis pain of the hip, hand, or knee that does not improve with exercise and weight loss.^[31] A 2015 review, however, found it provided only a small benefit in osteoarthritis.^[32]

Paracetamol has relatively little anti-inflammatory activity, unlike other common analgesics such as the nonsteroidal anti-inflammatory drug (NSAID) aspirin, and ibuprofen, but ibuprofen and paracetamol have similar effects in the treatment of headache. Paracetamol can relieve pain in mild arthritis, but has no effect on the underlying inflammation, redness, and swelling of the joint.^[33] It has analgesic properties comparable to those of aspirin, while its anti-inflammatory effects are weaker. It is better tolerated than aspirin due to concerns about bleeding with aspirin.

Based on a systematic review, paracetamol is recommended by the American Pain Society as a first-line treatment for low back pain.^[34] In contrast, the American College of Physicians found good evidence for NSAID but only fair evidence for paracetamol, while other systematic reviews have concluded that evidence for its efficacy is lacking entirely.^{[32][35][36][37]}

A joint statement of the German, Austrian, and Swiss headache societies and the German Society of Neurology recommends the use of paracetamol in combination with caffeine as one of several first-line therapies for treatment of tension or migraine headache.^[38] In the treatment of acute migraine, it is superior to placebo, with 39% of people experiencing pain relief at 1 hour compared with 20% in the control group.^[39]

Paracetamol combined with NSAID may be more effective for treating postoperative pain than either paracetamol or NSAID alone.^[40]

NSAID such as ibuprofen, naproxen, and diclofenac are more effective than paracetamol for controlling dental pain or pain arising from dental procedures; combinations of NSAID and paracetamol are more effective than either alone.^[41] Paracetamol is particularly useful when NSAID are contraindicated due to hypersensitivity or history of gastrointestinal ulceration or bleeding.^[42] It can also be used in combination with NSAID when these are ineffective in controlling dental pain alone.^[43] The Cochrane review of preoperative analgesics for additional pain relief in children and adolescents shows no evidence of benefit in taking paracetamol before dental treatment to help reduce pain after treatment for procedures under local anaesthetic, but the quality of evidence is low.^[44]

The efficacy of paracetamol when used in combination with weak opioids (such as codeine) improved for about 50% of people, but with increases in the number experiencing side effects.^[45][46] Combination drugs of paracetamol and strong opioids such as morphine improve analgesic effect.^[47]» (wikipedia)