Les anticholinergique dans la BPCO et l'asthme

Abstract

The parasympathetic nervous system regulates the tone of bronchial muscle and the secretion of mucus by the proximal airways. Its principal neuro transmitter is actylcholine and, though five different sub-types of muscarinic receptor are present in the respiratory apparatus, only the M1, M2 and M3 receptors play a functional role.Long acting anticholinergics (LAMA) improve respiratory function in patients with COPD, slow the rate of progression, reduce the frequency of admission to hospital and reduce respiratory mortality. In COPD patients with an increasing frequency of exacerbations a LAMA is probably justified as a first step, or a combination of long acting beta2 agonist (LABA) and inhaled corticosteroid (ICS). However, a comparison of these two treatment regimes is currently poorly supported by evidence. The introduction of a fixed combination of LAMA and LABA should not be considered as initial treatment. As well as dry mouth, urinary retention and raised intraocular pressure, the regular use of a LAMA may induce supraventricular tachycardia and atrial fibrillation, but it has not been shown to increase cardiovascular mortality.Many animal and human studies have shown a beneficial effect of LAMA on the course of asthma, with an improvement in respiratory function by a modulation of the calibre of the airways, but also by a reduction of mucus secretion and bronchial hyperreactivity. GINA 2014 mentions tiotropium as an additional treatment in asthmatic patients with uncontrolled symptoms and persistent flow limitation despite a LABA and an ICS in moderate or high dosage. Despite the improvements in respiratory function the studies show that tiotropium does not reduce the use of SABA and does not improve questionnaires of asthma control.