Prescription usage patterns of two formulations of paracetamol in osteoarthritis: Australia-wide experience 2008-11.

Abstract Around 7% of the Australian population report having osteoarthritis (OA), which is commonly managed in general practice. This study compared extended-release paracetamol (ERP; 665 mg) with standard immediate-release paracetamol (IRP; 500 mg) use in patients with OA. We used Pharmaceutical Benefits Scheme (PBS) claims data from a 10% random sample of concession card holders aged 50-85 years. A total of 46,255 patients were newly prescribed ERP or IRP for OA in the time window. Based on scripts filled, analgesic equivalent days (AEDs) were compared between ERP and IRP groups. In the first 12 months, the ERP and IRP groups had similar numbers of AEDs (188 and 189 respectively). ERP patients took eight more AEDs of non-steroidal anti-inflammatory drugs or cyclooxygenase-2 inhibitors and six fewer AEDs of opioid analgesics than IRP patients. ERP seems to have advantages over IRP as patients took it more regularly and were less likely to require opioid-containing analgesics. Less frequent dosing of the ERP formulation may explain the difference in usage patterns.