Dual release paracetamol in osteoarthritis of knee: a randomized controlled clinical trial.

BACKGROUND Paracetamol is recommended as first line agent for pain management in osteoarthritis (OA) by various guidelines. The main problem associated with management of osteoarthritis is long term patient compliance to paracetamol due to its frequent dosing. OBJECTIVE To evaluate the efficacy and safety of Paracetamol 650 mg dual release tablet twice daily (PCM 650 dual release) compared to paracetamol 500mg immediate release tablet thrice daily (PCM 500 IR) in the treatment of Knee OA. MATERIALS AND METHODS In this randomized, open label, parallel, active controlled clinical study, 250 patients of OA knee meeting inclusion criteria were randomized to receive either PCM 650 dual release two times daily or PCM 500 IR three times daily for 6 weeks. Patients were assessed at baseline, 2, 4 and 6 weeks. Primary efficacy measures were severity of pain (Visual Analogue Scale) and Knee injury and osteoarthritis outcome score (KOOS) subscale for pain at week 2, 4 and 6. Other KOOS subscales (symptoms other than pain, function in daily living, function in sport and recreation, quality of life) and patient's and physicians global assessment of therapy were included as secondary endpoints. RESULTS Both treatment groups showed improvement in primary endpoints at each evaluation visit. Patients receiving PCM 650 dual release showed significant improvement of pain in both primary endpoints at each study visit compared to patients receiving PCM 500 IR (p<0.001). PCM 650 dual release was significantly superior to PCM 500 IR for improvement in all KOOS subscales at each study visit (p<0.01). Less number of patients required additional rescue analgesics in PCM 650 dual release group (16% patients vs 26%, PCM 500 IR; p>0.05). Adverse effects were significantly less in PCM 650 dual release group (6% vs. 14% in PCM 500 IR; p<0.05). Patient's and physician's global assessment of therapy favoured PCM 650 dual release than PCM 500 IR (p<0.001). CONCLUSION Patients with symptomatic OA of the knee showed a greater improvement in pain and functional capacity with PCM 650 dual release than PCM 500 IR with better tolerability.