Practice guidelines for the treatment of acute migraine and chronic knee osteoarthritis with paracetamol: an expert appraisal on evolution over time between scientific societies

Background: Paracetamol is the commonest analgesic worldwide in primary care. Despite evidence-based recommendations for management of acute and chronic pain with paracetamol, practices seem vary considerably in its modalities of use, with or without restrictions, between renowned scientific societies and over time. Objective: Qualitative assessment of similarities, differences, and changes over time in guidelines for paracetamol use in acute and chronic pain. Methods: We focused on two common pain conditions for which paracetamol is widely used: acute migraine and chronic knee osteoarthritis (OA). In 19 guidelines (10 for acute migraine, 9 for chronic knee OA) from 10 scientific societies (AAN/AHS, ACR/AF, CHS, EFNS, EHF/LTB, ESCEO, EULAR, SFEMC, SRF, OARSI) published between 1997 and 2021, methods, results and conclusions were compared, between guidelines and over time. Results: In acute migraine, there was a shift from no recommendation for paracetamol or recommendation only for mild attacks to recommendation for mild to moderate attacks in updated guidelines, without restriction for use for four of the five scientific societies. In knee OA, although updated guidelines generally used the GRADE system, recommendations remained heterogeneous between scientific societies: recommendation without or with restrictions, or not recommended. Consensus is lacking regarding long-course safety and efficacy in acute pain and pain at mobilization. Conclusions: Most migraine guidelines now recommend paracetamol for mild to moderate pain. Knee OA guidelines vary on the use of paracetamol: a more holistic approach is needed for this condition, considering patient profile, disease stage, and pain management during physical activity to clarify its appropriate use.