Paracetamol use in dentistry

Paracetamol has analgesic and antipyretic actions and a low incidence of adverse effects compared with other analgesic drugs. However, in overdose, it can lead to severe hepatotoxicity (see Paracetamol poisoning: advice for primary care providers).

Although generally less effective than nonsteroidal anti-inflammatory drugs (NSAIDs) for acute dental pain, paracetamol is the drug of choice when NSAIDs are contraindicated because of its favourable safety profile.

Paracetamol is used in combination with other analgesics for the treatment of acute dental pain because this can result in enhanced pain management, or synergistic analgesia. As a component of multimodal analgesia, paracetamol reduces the requirement for opioids.

Paracetamol is available in multiple formulations (eg immediate-release, modified-release) and in combination with other drugs. Therefore, patients should be advised to consider the paracetamol content of all their medications, to avoid inadvertent ingestion of higher than recommended doses.

There is anecdotal evidence that liver toxicity can occur when therapeutic doses of paracetamol (4 g per day) are used in adults with intrahepatic glutathione depletion. Intrahepatic glutathione depletion can occur in people who are malnourished, cachectic or frail, or have alcoholism or decompensated cirrhosis. Liver toxicity is more likely when more than one of these conditions is present. Although cautious dosing is often advised in these people, there is a lack of consistent clinical evidence to support dose reduction. Dose reduction can be considered for complex patients (eg patients with decompensated cirrhosis or multiple conditions associated with glutathione depletion) but should not be undertaken routinely—expert advice may be needed. Inappropriate dose reductions can result in inadequate analgesia and, consequently, use of more harmful analgesics.

In obese children, the dose of paracetamol should be calculated using ideal body weight rather than actual body weight (see also c_dtg3-c34-s7.html#dtg3-c34-s7__tdtg3-c34-tbl6). For paracetamol dosing for children at risk of glutathione depletion, seek expert advice.

When prescribing paracetamol, the dose should be stated in grams or milligrams rather than the number of tablets or volume of liquid, unless the exact formulation to be administered has been specified.