Table 2.
Schematic overview of studies involving ibuprofen in human experimental pain models
| Reference | Dose | Model (pain assessments) | Main findings | |
|---|---|---|---|---|
| Acute models | [18] (n= 20) | 800 mg p.o. | Electrical stimulation (earlobe) PDT, PTT | PDT ↔, PTT ↑ (only for men) |
| [22] (n= 20) | 600 mg p.o. | Static pressure pain (interdigital web) VAS | VAS ↓ | |
| [10] (n= 30) | Topical application (5%) | Intradermal infusion of phosphate buffered solution (pH 5.2) AUCVAS | AUCVAS↓ | |
| [21] (n= 24) | 3 × 400 and 3 × 800 mg p.o. | Repeated pinching (interdigital web) VAS | VAS ↔ | |
| [20] (n= 18) | 400 and 800 mg p.o. | Stimulation of nasal mucosa by CO2 (phasic pain) and dry air (tonic pain), VAS, evoked brain potentials (only phasic pain) | Pain ratings to CO2 stimulation and dry air ↔ | |
| Evoked potentials ↓ (dose related manner) | ||||
| [17] (n= 8) | 600 mg p.o. | Electrical skin stimulation nociceptive reflex | Reflex threshold ↑ | |
| [23] (n= 10) | 400 and 800 mg p.o | Laser skin stimulation PDT | PDT↑ for both doses, no dose–response relation was seen | |
| [24] (n= 12) | 600 mg p.o. | Cold pressor test PDT, peak pain (VAS), AUCVAS | No parameters were affected | |
| [32] (n= 24) | 400 mg p.o. and topical 2 mg cm−2 | Pinprick PDT | PDT ↔ | |
| Models inducing hyperalgesia | [32] (n= 24) | 400 mg p.o. and topical 2 mg cm−2 | Freeze lesion: | p.o. treatment: PDT in primary HA area and secondary HA area ↑ |
| Area of primary and secondary HA: PDT to punctuate stimulation | Topical treatment: PDT in primary HA area ↑, PDT in secondary HA area ↔ | |||
| [34] (n= 34) | 800 mg p.o. | UVB radiation | Heat PDT and PTT ↑ | |
| Primary HA: | ||||
| Heat PDT and PTT | ||||
| [33] (n= 21) | 600 mg p.o. | HA to repetitive pinching to interdigital web VAS | Decrease of VAS (HA) to repetitive pinching was reduced | |
| UVB radiation | Heat PDT ↑ | |||
| HA evaluated by: heat PDT, nonpainful sensations and PDT to mechanical stimulation | Mechanical PDT ↑ | |||
| Nonpainful sensations unaffected | ||||
| [22] (n= 20) | 600 mg p.o. | Burn injury spontaneous pain (VAS during burn) | VAS during burn ↔ | |
| Area of secondary HA to pinprick and allodynia to stroking | Area of secondary HA to stroking and brushing ↔ | |||
| VAS to brushing in secondary HA area | VAS to brushing↓ | |||
| HA to static pinching to interdigital web VAS | VAS to static pinching ↓ | |||
| [21] (n= 24) | 3 × 400 mg p.o. and 3 × 800 mg p.o. at 2-h intervals | Freeze lesion | Mechanical HA after freeze lesion ↓ | |
| In area of primary HA: PDT to heat and mechanical stimuli | Thermal HA after freeze lesion ↔ | |||
| Topical capsaicin | Capsaicin induced allodynia ↔ | |||
| Allodynia to brushing | Increase in VAS (HA) from repetitive pinching was prevented | |||
| HA to repetitive pinching to interdigital web VAS | ||||
| [31] (n= 10) | 3 × 400 mg p.o. and 3 × topical application (5%) (for 3 days) | Post-exercise jaw-muscle soreness PDT and PTT to subsequent pressure algometry | PDT↓ (topical>systemic) | |
| PTT ↔ |
In the column ‘Model’ the method for pain assessment is normal font, and the method for pain induction is bold. PDT, pain detection threshold; PTT, pain tolerance threshold; AUC, area under curve; VAS, visual analogue scale; HA, hyperalgesia.