RESUMEN
Post-viral cough is a type of cough originating from upper respiratory tract infections that persists after the infection is resolved. Although it was hypothesized that bronchodilators might have a role in the management of post-viral cough, a clear demonstration of their efficacy is missing. Therefore, we tested the efficacy of a combination of a ß-agonist and an anticholinergic agent in reducing post-viral cough with a randomized, double blind, placebo controlled clinical trial. Patients were treated for 10 days with either a nebulized combination of salbutamol 1.875 mg/0.5 mL and ipratropium bromide 0.375 mg/0.5 mL, or a placebo, and followed up for another 10 days. Daytime and nighttime cough severity and spirometry testing were assessed before starting treatment, after 10 and 20 days. Ninety-two patients were randomized to receive placebo (n = 46) or the active treatment (n = 46); nine of them (4 in the placebo group, 5 in the active treatment group) dropped out from the study. Daytime and nighttime cough severity were significantly reduced in both groups during the study period, but the reduction was more prominent in the active treatment group vs. placebo after 10 days of treatment (P = 0.003 for day cough; P = 0.061 for night cough), whereas at the end of follow-up period cough severity was comparable between the two groups. Small but significant increases in spirometric parameters were observed in the active treatment vs. placebo group, although at the end of follow-up these values returned to be comparable to placebo. The frequency of adverse events was not significantly different between the two groups of patients. We concluded that a combination of a ß-agonist and an anticholinergic agent can effectively reduce post-viral cough, and can thus represent a valid option for this type of cough.
Asunto(s)
Albuterol/uso terapéutico , Broncodilatadores/uso terapéutico , Tos/tratamiento farmacológico , Ipratropio/uso terapéutico , Administración por Inhalación , Adulto , Anciano , Albuterol/administración & dosificación , Broncodilatadores/administración & dosificación , Tos/etiología , Método Doble Ciego , Quimioterapia Combinada , Femenino , Humanos , Ipratropio/administración & dosificación , Masculino , Persona de Mediana Edad , Infecciones del Sistema Respiratorio/complicaciones , Infecciones del Sistema Respiratorio/virología , Espirometría , Adulto JovenRESUMEN
This study characterised the in vitro and in vivo profiles of two novel long-acting muscarinic antagonists, aclidinium bromide and glycopyrronium bromide, using tiotropium bromide and ipratropium bromide as comparators. All four antagonists had high affinity for the five muscarinic receptor sub-types (M1-M5); aclidinium had comparable affinity to tiotropium but higher affinity than glycopyrronium and ipratropium for all receptors. Glycopyrronium dissociated faster from recombinant M3 receptors than aclidinium and tiotropium but more slowly than ipratropium; all four compounds dissociated more rapidly from M2 receptors than from M3 receptors. In vitro, aclidinium, glycopyrronium and tiotropium had a long duration of action at native M3 receptors (>8 h versus 42 min for ipratropium). In vivo, all compounds were equi-potent at reversing acetylcholine-induced bronchoconstriction. Aclidinium, glycopyrronium and ipratropium had a faster onset of bronchodilator action than tiotropium. Aclidinium had a longer duration of action than glycopyronnium (time to 50% recovery of effect [t½ offset] = 29 h and 13 h, respectively); these compare with a t½ offset of 64 h and 8 h for tiotropium and ipratropium, respectively. Aclidinium was less potent than glycopyrronium and tiotropium at inhibiting salivation in conscious rats (dose required to produce half-maximal effect [ED50] = 38, 0.74 and 0.88 µg/kg, respectively) and was more rapidly hydrolysed in rat, guinea pig and human plasma compared with glycopyrronium or tiotropium. These results indicate that while aclidinium and glycopyrronium are both potent antagonists at muscarinic receptors with similar kinetic selectivity for M3 receptors versus M2, aclidinium has a longer dissociation half-life at M3 receptors and a longer duration of bronchodilator action in vivo than glycopyrronium. The rapid plasma hydrolysis of aclidinium, coupled to its kinetic selectivity, may confer a reduced propensity for systemic anticholinergic side effects with aclidinium versus glycopyrronium and tiotropium.