Table 1.

Overview of the literature search strategy.

Objective	Search Terms
Substance	PEA OR palmitoylethanolamide OR n palmitoyl ethanol amine OR um-pea OR palmidrol OR Impulsin
Population	human OR female OR male OR proband OR patient OR volunteer
Indication	pain OR chronic pain OR acute pain OR neuropathic pain OR nociceptive pain OR allodynia OR analgesia OR arthralgia OR brachialgia OR causalgia OR cephalalgia OR cephalic OR cervicodynia OR colic OR eudynia OR fibromyalgia OR headache OR hyperalgesia OR hypoalgesia OR hyperpathia OR maldynia OR migraine OR neuralgia OR nociceptive OR odontalgia OR opthalmodynia OR vulvodynia OR otalgia OR radiculopathy OR toothache OR orchidodynia OR coccygodynia OR CRPS OR nuchalgia OR lumbalgia OR lumboischialgia OR cervicobrachialgia
Study type	prospective OR randomised OR randomized OR controlled OR observational OR trial