Analgesic efficacy and side effects of oral tramadol and morphine administered orally in the treatment of cancer pain

AIMS OF THE STUDY: To assess the analgesic efficacy and side effects of tramadol and equianalgesic doses of morphine and to assess the quality of life (QL) in patients suffering from cancer pain and to establish equianalgesic doses of oral tramadol and morphine. PATIENTS AND METHODS: Fourty opioid-naive patients with moderate, strong or very strong cancer pain (verbal scale) or at least 45 mm on VAS scale, were treated with tramadol (20 patients) or morphine (20 patients). During the first 7 days the pain was stabilised by the use of immediate release forms of tramadol (drops, capsules) or morphine (water solution). After 7 days, if a satisfactory pain relief was achieved and appropriate daily doses were applied (tramadol 150-600 mg, morphine 20-200 mg) patients were switched to controlled release forms of tramadol – Tramal Long (Retard) tablets – or sustained release morphine (MST Continus tablets or M-eslon capsules) for 28 days. QL was assessed by QLQ C 30 questionnaire. Pain intensity was appraised by VAS and verbal scale, side effects by verbal scale. RESULTS: The duration of treatment was 3-310 (mean 87.15±78.23) days for Tramal Retard and 5-502 (mean 100.05±102.67) days for morphine MST Continus and M-eslon. Daily doses were as follows: 200- 600 (mean 322.22±116.60) mg for tramadol and 20-270 (123.5±78.15) mg for morphine. Satisfactory analgesia was achieved in both groups. However, in patients with neuropathic pain better analgesic effect was noted in the morphine group (significant difference in VAS scale after first week of the treatment). 80% of patients in both groups preferred the treatment with controlled release forms of tramadol and morphine. The treatment was well tolerated, 17 patients in tramadol group and 18 in morphine group completed the study. More side effects were noted in morphine group, however significant differences appeared only in drowsiness, difficulties in passing urine, sweating and dizziness intensity. QL results revealed better global QL and less fatigue after 35 days of the tramadol treatment. CONCLUSIONS: Tramadol and equianalgesic doses of morphine (up to 270 mg/day) in immediate and controlled release forms are effective in the treatment of different types of moderate and severe cancer pain. Tramadol is less effective in patients with neuropathic pain. Both drugs can be safely used at home. Better global QL and less fatigue was observed after 35 days of the tramadol treatment. Tramadol is recommended in patients with moderate pain (VAS 30-54 mm) and morphine in patients with severe and very severe pain (VAS >54 mm). Equianalgesic doses of tramadol and morphine administered orally are 4:1.