Tramadol plus metamizole combined or not with anti-inflammatory drugs is clinically effective for moderate to severe chronic pain treatment in cancer patients

Abstract

Objective To test the effectiveness and safety of tramadol plus metamizole combined or not with a non-steroidal anti-inflammatory drug (NSAID) for treating moderate to severe chronic neoplastic pain in dogs, and its impact on quality of life (QL). Study design Prospective, uncontrolled, open-label, clinical study. Animals Sixty nine client-owned dogs with multiple forms of cancer and visual analog scale (VAS) pain score 40 after receiving NSAIDs for at least 7days. Methods The MN group received metamizole+NSAID, MNT group received metamizole+NSAID+tramadol and MT group received metamizole+tramadol. Pain was scored by the 0 to 100mm VAS (0=no pain, 100=worst pain) and analgesic therapy was considered effective if 25mm differences in VAS scores were observed between day 0 and the follow ups. The QL was evaluated according to a 0 to 36 scoring method for dogs (0=worst, 36=best) and side effects were recorded. Data were registered at day 0 (baseline) and at the first and second follow ups (7 and 14days after day 0, respectively). Results The MN group had less analgesia at day 7 (25%) and day 14 (42%) than MNT (59%, p=0.0274; 76%, p=0.0251, respectively) and MT groups (69%, p=0.0151; 81%, p=0.0341, respectively). The QL scores were lower in the MN group at the first (score 23) and second follow up (score 26) than in MNT (27, p=0.0847; 30, p=0.0002) and MT (28, p=0.0384; 31, p=0.0001) groups. Side effects were more commonly observed in the MN group (87%) than in MNT (24%, p<0.0001) and MT groups (25%, p=0.0003) at the first follow up. Conclusions and clinical relevance Tramadol plus metamizole combined or not with NSAID were well tolerated and clinically effective to treat moderate to severe pain in dogs with cancer and improved QL.