Paracetamol

Also known as acetaminophen, paracetamol is commonly prescribed for a wide spectrum of pain, including knee osteoarthritis (OA).

There is strong evidence that paracetamol provides moderate improvement in pain associated with OA. It is more effective than a placebo but less effective than anti-inflammatory medications (NSAIDs). However, when used at the recommended dose, paracetamol is safer than NSAIDs. Guidelines developed by several professional organisations recommend paracetamol as the firstline therapy.

About

Paracetamol is a medication used to relieve pain and fever. Unlike anti-inflammatory medications it does not cause gastric irritation or affect platelet aggregation. Paracetamol works by blocking the synthesis of prostaglandins, substances in the body that are involved in inflammation and pain. It has a modest effect on peripheral prostaglandin synthesis and so has only a weak anti-inflammatory effect. It has a strong effect on prostaglandin synthesis in the central nervous system which is responsible for its strong effects on pain and fever.

Paracetamol is usually recommended as the first medication to be used in osteoarthritis pain. This is especially the case in patients who have mild to moderate pain, without signs of inflammation, and when the OA is related to activity. It is usually taken as needed but if this does not provide adequate relief, it can be taken three or four times daily.

Be Aware

Paracetamol is available as a range of commercial formulations with different trade names. Many of these are available as over-the-counter medications without a prescription. Some trade names clearly indicate the medication contains paracetamol – such as Panadol, Panadol Osteo and Panamax. In other cases it is less clear. Cold and flu medications such as Codral, Codalgin and Dimetapp may also contain paracetamol.

Paracetamol has been shown to be a safe medication if you do not exceed the recommended daily dose. This is between 3g and 4g per 24 hours depending on specific patient circumstances including age and other medical conditions. If you take more than this dose, paracetamol can be extremely dangerous, resulting in liver damage or death. Paracetamol can also react with other medications and alcohol.

It is extremely important not to take more than one medication with paracetamol in it, and discuss any other mediations you are taking with your doctor. If you take paracetamol on a regular basis your doctor may advise you to undergo regular blood tests to check your liver function.