A double-blind evaluation of the analgesic efficacy and toxicity of oral ketorolac and diclofenac in cancer pain. The TD/10 recordati Protocol Study Group

To compare the analgesic efficacy and toxicity of the nonsteroidal anti-inflammatory analgesic drug, ketorolac (Toradol, Recordati spa, Milan) 10 mg p.o. (t.i.d.) with diclofenac (Voltaren, Novartis Farma, Origglo, VA) 50 mg p.o. (t.i.d.) in cancer patients with moderate to severe chronic pain.The study was a multicenter randomized double-blind cross-over trial. Each treatment lasted 7 days, after which the patients crossed over to the other drug. Pain intensity was evaluated by the visual analogue scale (VAS) after the first dose and by the 5-point verbal rating scale (VRS) by the patient and by the physician following the 7-day treatment.A total of 138 advanced cancer patients were enrolled in the study. Overall 251 single-dose administrations (117 cross-over observations) and 257 multiple treatments (127 cross-over experiments) were assessable. After a single administration of ketorolac and diclofenac, no significant difference could be observed in analgesic activity, as indicated by the area under the pain-intensity time curve (AUC0-8), in the maximum efficacy, or the duration of efficacy of the two drugs. The Westlake confidence intervals of the AUC0-8 ratio (ketorolac: diclofenac) (1.07; 90% CI, 0.94-1.19), of the maximum efficacy ratio (1.03; 90% CI, 0.92-1.14), and the duration of efficacy ratio (1.05; 90% CI, 0.97-1.11) showed the bioequivalence of the two drugs. Satisfactory pain relief was reported for multiple 7-day treatments, with no significant differences between the two therapies: according to the physician's evaluation, in 93/128 (73%; 95% CI, 65-80%) ketorolac treatments and 91/129 (71%; 95% CI, 63-78%) diclofenac treatments; according to the patient's evaluation, in 83/128 cases (65%; 95% CI, 57-73%) after ketorolac and in 74/129 cases (57%; 95% CI, 49-66%) after diclofenac. Adverse symptoms were acceptable with both drugs. Interestingly, a pronounced sequence effect was found: gastric disturbances after ketorolac were observed mainly (10 out of 15 observed events) when the drug was given to patients pretreated with diclofenac.