Julien Rossignol et al. (2019) from Inserm and University Paris Descartes, Paris, France published a paper on the effects of high dose topical amitriptyline in painful chemotherapy-induced neuropathy: 10%. We advocated such high dose already years ago based on our clinical data. (Kopsky DJ, Hesselink JM (2012) High doses of topical amitriptyline in neuropathic pain: two cases and literature review. Pain Pract 12(2):148–153). Rossignol et al organized a prospective, pilot study and they could show that 10% topical amitriptyline cream alleviated chemotherapy-induced neuropathic pain in cancer patients, with no local or systemic safety concerns. Baseline pain intensity was moderate to severe: mean pain scores NRS 7. After 1 week of topical amitriptyline treatment, there was already a decrease of at least 3 points in all patients.
We took up high dosing in 2012, and meanwhile have also gone to high dose topical phenytoin (10-20%), with good efficacy and virtually no side effects
Ref: Rossignol J, Cozzi B, Liebaert F, Hatton S, Viallard ML, Hermine O, Greco C. High concentration of topical amitriptyline for treating chemotherapy-induced neuropathies. Support Care Cancer. 2019 Jan 4. doi: 10.1007/s00520-018-4618-y.