Using parenteral and rectal formulations of paracetamol or NSAIDs for acute nociceptive pain

Paracetamol or nonsteroidal anti-inflammatory drugs (NSAIDs) can be administered parenterally or rectally to patients with acute nociceptive pain who cannot take oral medications, or who have impaired gastrointestinal absorption. Parenteral administration is usually preferred over rectal administration because of its rapid onset of effect and more predictable pharmacokinetics. However, rectal administration may be used if both oral and parenteral administration are not possible (eg in general practice). If parenteral or rectal therapy is used, use the lowest effective dose and change to the oral route, or stop therapy, as soon as possible.

Before using an alternative route of administration, consider whether nonpharmacological management alone would be adequate.