Clinical data
In the clinical trials, PEA was used for periods ranging from 14 days to 120 days, and the doses ranged from 300 mg to 1200 mg daily administered as oral tablets. The commonest form of evaluation was the visual analogue scale (VAS), where the patient makes a subjective assessment of her/his pain level on a 10 cm line where the left side represents no pain, and the right side represents the worst imaginable pain. All available clinical trials reported significantly reduced pain intensity and an almost complete absence of unwanted effects.
Table. Clinical trials investigating the effect of PEA in pain.
| Type of study | No. of patients | Type of pain | PEA dosage | Treatment length | Outcome (all VAS scale unless marked with ¶ or **) | Unwanted effects |
| Double blind randomized controlled multi‐centre, placebo (Guida G, et al. 2010) | 636 (1/3 placebo) | Low back pain (lumbosciatica) | 1 or 2 × 300 mg daily | 21 days | 600 mg better than 300 mg, both doses significantly better than placebo at t = 21 days | None reported |
| (Observational) prospective cohort (Gatti A, et al., 2012) | 610 (564 completions) | Chronic pain of different etiopathogenesis | 1200 mg daily for 3 weeks followed by 600 mg daily for 4 weeks | 49 days | Significant decrease in pain intensity in all patients (P = 0.0001)¶ | None reported |
| Non‐randomized, non‐controlled, PEA as add‐on compared to only standard treatment* (Dominguez CM, et al. 2010)[iii] | 118 (64 received PEA) | Low back pain (lumbosciatica) | 600 mg daily | 30 days | Significant changes for both groups, a slightly larger decrease in pain intensity with PEA compared to standard treatment.* No significant change in ODI | None reported |
| Double blind, randomized, controlled, placebo (Canteri L, 2010) | 111 (1/3 placebo) | Lumbosciatic pain | 1 or 2 × 300 mg daily | 21 days | Significant reduction of pain intensity with PEA regardless of simultaneous treatment with other drugs compared to placebo at days 21 | None reported |
| Observational (Del Giorno R, 2015) | 80 | Fibromyalgia | Starting with 600 mg daily for 1 month following 300 mg daily for month 2–3 | 6 months (PEA 3 months) | Addition of PEA to the treatment regimen significantly reduced VAS pain scores further | None reported |
| Randomized, controlled (Crestani F, 2013) | 30 (1/2 acupuncure) | Radiculopathy | 600 mg daily | 120 days | Significant decrease in chronic pain intensity with PEA compared to acupuncture treatment only** | Unknown |
| Open‐label (Cocito D, 2014) | 30 | Diabetic or traumatic neuropathic pain | 1200 mg daily | 40 days | Significant reduction of pain intensity. VAS, health questionnaire five dimensions for quality of life (EQ‐ED50) and NP Symptom Inventory (NPSI) used | NS |
| Open‐label (Desio P. 2010) | 30 | Neuropathic pain, different types | 600 mg daily (combined with pregabalin) | 45 days | Significant reduction of pain intensity | None reported |
| Open‐label (Schifilliti C, 2014) | 30 | Peripheral diabetic neuropathy | 600 mg daily | 60 days | Significant reduction in pain intensity [Total Symptom Score TSS]** | None reported |
| Controlled trial (Conigliaro R, 2011) | 26 | Carpal tunnel syndrome | 600 mg or 1200 mg daily | 30 days | Significant improvement of CTS induced median nerve latency time. Also improvement of subjective discomfort, and Tinel's sign** | None reported |
| Triple‐blind, randomized, controlled (Marini I, 2012) | 24 (1/2 ibuprofen) | Temporomandibular joint inflammatory pain | 900 mg daily for 7 days and then 600 mg daily for 7 days more | 14 days | Significantly larger reduction in pain intensity compared to ibuprofen treatment on day 14 | None reported |
| Open‐label (Truini A, 2011) | 20 | Chemotherapy‐induced neuropathy | 600 mg daily | 60 days | Significant reduction in pain intensity** | Unknown |
Abbreviations: NS, not stated in the article; NRS, Numerical rating scale; UM, Ultramicronized; VAS, Visual analogue scale.
* NSAIDs, analgesics, muscle relaxants, corticosteroids; the exact treatment differed for patients / treatment centres.
¶ NRS used.
** Other or unidentified evaluation method. ODI, Oswestry Disablity Index (measures quality of life in patients with low back pain).