Endoscopic evaluation of the gastro-duodenal tolerance of short-term analgesic treatment with 25 mg diclofenac-K liquid capsules

Summary Background Diclofenac‐potassium (diclofenac‐‐K) 25 mg liquid capsule is absorbed more quickly than the tablet formulation. It offers potential for rapid pain relief, but may alter gastro‐duodenal tolerability. Aim To evaluate the gastro‐duodenal tolerance of diclofenac‐K 25 mg liquid capsules vs. diclofenac‐K 12.5 mg tablets, acetylsalicylic acid (ASA) 500 mg tablets and ibuprofen 200 mg liquid capsules. Methods In an endoscopist‐blinded, randomised, parallel‐group study, volunteers received 15 doses of diclofenac‐K 25 mg liquid capsules (n = 36), diclofenac‐K 2 × 12.5 mg tablets (n = 36), ibuprofen 2 × 200 mg liquid capsules (n = 24) or ASA 2 × 500 mg tablets (n = 36) over 5 days. The primary outcome was the incidence of erosive gastro‐duodenal lesions at Day 6. Secondary outcomes included modified Lanza score and change in gastric mucosal prostaglandin synthesis. Results The lowest incidence of erosive gastro‐duodenal lesions was with diclofenac‐K liquid capsules (53%), compared to 61% with diclofenac‐K tablets (P = 0.52), 75% with ibuprofen (P = 0.08) and 94% with ASA (P = 0.001). Results were similar for the Lanza scores, although diclofenac‐K liquid capsules were significantly superior to ibuprofen liquid capsules (P = 0.04). Diclofenac‐K liquid capsules inhibited prostaglandin synthesis by 52% compared to 64% for diclofenac‐K tablets (P = 0.10), 50% for ibuprofen (P = 0.85) and 79% for ASA (P = 0.002). With respect to safety, adverse events were most frequent in the ASA group, predominantly gastrointestinal events. Conclusions Mucosal injury with diclofenac‐K liquid 25 mg liquid capsules was similar to diclofenac‐K 25 mg tablets, significantly lower than ASA 1 g tablets and showed some superiority over ibuprofen 400 mg liquid capsules (EudraCT Number 2009‐011278‐14).