| Literature DB >> 25110575 |
Cherubino Di Lorenzo1, Gianluca Coppola2, Valeria La Salvia3, Francesco Pierelli4.
Abstract
BACKGROUND: Chronic headache is an incapacitating condition afflicting patients at least for 15 days per month. In the most cases it is developed as a consequence of an excessive use of symptomatic drugs. CASE: Here we report the case of a 34 year-old man suffering from chronic headache possibly related to the overuse of naphazoline nitrate nasal decongestant, used to treat a supposed chronic sinusitis. However, the patient did not suffer from sinusitis, but from a medication overuse headache (ICHD-II 8.3; ICD-10 44.41) that appeared to be due to excessive use of naphazoline.Entities:
Year: 2013 PMID: 25110575 PMCID: PMC4111119 DOI: 10.12688/f1000research.2-237.v1
Source DB: PubMed Journal: F1000Res ISSN: 2046-1402
Figure 1. Late events induced by naphazoline that could cause headache.
a. Naphazoline activates α1 receptors that are associated with G-proteins that cause the activation of phospholipase C. Phospholipase C cleavesphosphatidyl-inositol 4,5-bisphosphate (PIP2) into two second messengers, inositol 1,4,5-trisphosphate (IP3) and diacylglycerol (DAG) which in turn cause an increase in the level of calcium and protein kinase C. Diacylglycerol, by DAG lipase, takes part in the creation of arachidonic acid which is a precursor in the production of prostaglandins (PGs), mediated by cyclooxygenase (COX). The higher concentration of intracellular calcium allows an increase in the complex of calcium-calmodulin and therefore the activation of constitutive nitrous oxide synthetase (cNOS) with the generation of nitric oxide [8, 9]. b. Naphazoline nitrate can contribute to the production and release of further NO by a chemical reduction of the naphazoline salt. Prostaglandins and nitric oxide contribute to the activation of nociceptors and the transmission of the pain pulse from the periphery to the centre [10]. Consequently there is a release of substances such as potassium ions, P-substance, bradykinin, histamine, serotonin and CGRP that keep nociceptors active and result in vasodilatation and extravasation of plasma proteins from the vessels.
Figure 2. Possible early events that induce peripheral analgesic effect.
a. Naphazoline activates alpha1 receptors that are associated with G-proteins that cause the activation of phospholipase C. Phospholipase C cleaves phosphatidyl-inositol 4,5-bisphosphate (PIP2) into inositol 1,4,5-trisphosphate (IP3). Consequently there is a smooth muscle contraction due to an increase of intracellular calcium. b. Alpha-Receptors on immune cells release β-endorphins that cause opioid analgesia. c. Activation of alpha2 adrenoceptors in the Locus Coeruleus and spinal cord provokes the depression of nociceptive transmission [12].