Which parameters affect pain reduction in acute headache treatment? Analysis of data from an observational study on the fixed-dose combination ibuprofen+caffeine

Introduction and objective: Headache patients expect fast onset of action and complete pain relieve from their acute treatments. We have run a pharmacy‐based observational study in patients buying a specific analgesic (400 mg ibuprofen +100 mg caffeine) and analyzed parameters of patient's perception of efficacy measures. Patients and methods: A pharmacy‐based exploratory survey was conducted in German community pharmacies (Gaul et al. 2022). Patients buying a fixed‐dose analgesic combination product to treat their headache (400 mg ibuprofen+100 mg caffeine) were offered a questionnaire which contained ‐among others‐ questions about time to onset of pain relief (OPR) after intake of the medication (categories: 0‐5, 6‐15, 16‐30, 31‐45, 46‐60, and >60min), assessment of time to onset of pain relief (AOPR; categories: very fast, fast, moderately fast, and slow), assessment of efficacy (categories very good, good, moderately good, bad), and pain intensity (on a 0‐10 numerical pain rating scale, NRS) at baseline and 2 h after intake. Percent pain intensity difference (%PID)= 100∗ (NRS 2h ‐ NRS baseline)/NRS baseline. Spearman's rank correlation tests were performed to test for statistical significance. Results: In total data from 827 patients could be analyzed. Correlation of %PID at 2 h with assessment of efficacy was high (Spearman r=0.487, p<0.0001), and assessments corresponded well with those from a randomized controlled trial on analgesic effects of the fixed dose combination aspirin+paracetamol+caffeine for treating acute headache (Aicher, 2012). OPR corresponded well with %PID at 2h (Spearman r=0.294, p<0.0001), which was also the case for AOPR and %PID at 2 h (Spearman r=0.319, p<0.0001). I Conclusion: This investigation showed that early onset of pain relief of an analgesic corresponds well with pain reduction at 2 h, as well as patients' assessment of overall efficacy. This further underlines the importance of fast onset of action for acute headache treatments.