Does l-ascorbic acid have an analgesic effect?

Abstract

The case report presented by Arabadzhiev et al. [1] aims to show that l-ascorbic acid (3000mg/day, for 10 days) can control persistent severe pain (NRPS grade 8/10) persistent on a mandibular incisor which does not retroceded despite 6 weeks of drug treatment (antibiotic therapy, tramadol, ibuprofen, noramidopyrine), dental treatment (root canal treatment, apicectomie) physical treatment (diode laser) and infiltration of bupivacaine 0.5%. Faced with such a complex clinical status, three-dimensional imaging would have been of great help in the diagnosis. Technetium-99m bone scintigraphy would also have ruled out an infectious bone etiology [2]. The extrapolation of the therapeutic efficacy of ascorbic acid on pain associated with colorectal and gastric cancers, bone metastases, post herpetic neuralgia or labial herpes to pulp necrosis pain still remain controversial. l-ascorbic acid has an anti-inflammatory and antioxidant action and acts on the central nervous system and the patient’s immunity. It would be necessary to know the metabolic profile and the immunological status of the patient as well as her antecedents. It seems risky to systematize ascorbic acid in persistent post-surgical pain without prior dosage, the daily intake being already around 100mg. The contraindications of ascorbic acid (calcium oxalate urolithiasis, phenylketonuria, primary hemochromatosis, G6PD deficiency or thalassemia etc.) must also be evaluated when high doses are proposed. Vitamin C, especially in high doses, is a source of increase in serotonin by hydrolization of triptophan which can, on the contrary, be a source of sensitization to pain as serotonin acts on the serotoninergic receptors 5-HT1A, 5-HT1B, and 5-HT3 which are pro-nociceptive [3]. The pronounced role of serotonin is well identified at the periphery, locally during inflammatory processes, but it is also exerted during nerve damage. Regarding the lack of effectiveness of the diodlaser 810 nm with an intensity of 1.6W and 300 J/session reported by the authors, it is noticable that low-level laser used