Is there an alternative to diclofenac i/m injections for rapid relief of severe pain? Results of randomized controlled and partially blind forsage study

Diclofenac Potassium sachets (DPS) is a new faster-absorption and rapid onset of pain relief drug dosage form of Diclofenac with high analgesic potential. Objective . To assess efficacy and safety of Diclofenac sachets and intramuscular injections in relieving acute pain in patients with rheumatic diseases (RDs). Materials and methods : The study group included 30 RD patients, 53.3% females and 46.7% males, mean age 41.8 ± 10.7 years, with severe acute pain (≥7 cm VAS pain rating, VAS 0-10 cm). After signing informed consent patients were randomized into DPS 50 mg t.i.d. and Diclofenac 75 mg i/m b.i.d. The first administration of Diclofenac was blind, i.e., patients from both groups were also administered placebo – either placebo injection in Group 1 randomized to sachet or placebo sachet in Group 2. The study lasted for 3 days. Level of analgesia was assessed in 15, 30, 60, 120, 180 minutes after the first administration, then three times a day during two following days and in the morning on day 4. Serum levels of CRP, IL-6 and P substance biomarkers were also monitored. Results . Pain relief in Group 1 was documented already in 15 min after administration – from 8.1±0.8 to 5.7±1.7 cm VAS (р=0.012), with continuing increase of analgesic effect thereafter. Group 2 demonstrated significant pain relief in 1 hour after Diclofenac administration – from 7.6±0.7 to 4.5±1.9 cm VAS (р=0.04). Based on obtained data analgesic effect was more powerful in Group 1 vs Group 2 in 15 and 30 minutes after drug administration (р=0.019; р=0.037). Starting from the 3rd hour post-administration there was no statistically significant difference in pain intensity between the two groups. Final assessment in the morning on day 4 showed significant pain reduction by 4.5±2.6 cm VAS in Group 1 vs baseline, and by 3.6±1.4 cm VAS in Group 2 (p=0.545). Functional improvement in both groups reached 3.7±1.9 and 3.3±1.3 cm VAS, respectively (p=0.837). The results were rated as “good” and “excellent” by 77.0% in Group 1, and 61.5% – in Group 2 (р=0.302). No correlation between decreasing pain intensity and fluctuating CRP, IL-6, and substance P concentrations was established. Three patients from Group 1 reported new-onset dyspepsia, resulting in discontinuation of treatment in 2 of them. Similarly, 2 discontinuations occurred in 2 patients with new-onset dyspepsia in Group 2, plus one additional withdrawal due to gastric ulcer and elevated blood pressure. Conclusion . DPS is not inferior to i/m Diclofenac injections in terms of analgesic potential and rapid onset of pain relief. Oral intake is associated with fewer adverse reactions compared to i/m injections.