![]() ![]() Mitchell 2 has shown that particles less than 10 microns should be retained in the respiratory tract satisfactorily. Most of the nebulizers tested will supply a high proportion of the drug solution as particles of less than 10 microns in diameter. MUCOMYST is usually administered as fine nebulae and the nebulizer used should be capable of providing optimal quantities of a suitable range of particle sizes.Ĭommercially available nebulizers will produce nebulae of MUCOMYST satisfactory for retention in the respiratory tract. ![]() Because animal reproduction studies may not always be predictive of human responses, this drug should be used during pregnancy only if clearly needed. There are, however, no adequate and well-controlled studies in pregnant women. These have revealed no evidence of impaired fertility or harm to the fetus due to acetylcysteine. Reproduction studies of MUCOMYST with isoproterenol have been performed in rats and of acetylcysteine alone in rabbits at doses up to 2.6 times the human dose. In the pregnant rat (30 rats per group), twice-daily exposure to an aerosol of acetylcysteine and isoproterenol for 30 or 35 minutes from the 15th day of gestation through the 21st day postpartum was without adverse effect on dams or newborns. No teratogenic effects were observed among the offspring. In the rat, two groups of 25 pregnant females each were exposed to the aerosol for 30 and 35 minutes, respectively, twice a day from the 6th through the 15th day of gestation. Teratology and a perinatal and postnatal toxicity study in rats were performed with a combination of acetylcysteine and isoproterenol administered by the inhalation route. ![]() In the rabbit, two groups (one of 14 and one of 16 pregnant females) were exposed to an aerosol of 10% acetylcysteine and 0.05% isoproterenol hydrochloride for 30 or 35 minutes twice a day from the 6th through the 18th day of pregnancy. Acetylcysteine was found to be nonteratogenic under the conditions of the study. In a teratology study of acetylcysteine in the rabbit, oral doses of 500 mg/kg/day (2.6 times the human mucolytic dose) were administered to pregnant does by intubation on days 6 through 16 of gestation. Pregnancy: Teratogenic Effects: Pregnancy Category B If bronchospasm progresses, the medication should be discontinued immediately. Most patients with bronchospasm are quickly relieved by the use of a bronchodilator given by nebulization. The converse is also true patients who have had inhalation treatments of acetylcysteine without incident may still react to a subsequent inhalation with increased airways obstruction. ![]() Even when patients are known to have reacted previously to the inhalation of an acetylcysteine aerosol, they may not react during a subsequent treatment. Those patients who are reactors cannot be identified a priori from a random patient population. Occasionally, patients exposed to the inhalation of an acetylcysteine aerosol respond with the development of increased airways obstruction of varying and unpredictable severity. Significant mucolysis occurs between pH 7 and 9.Īcetylcysteine undergoes rapid deacetylation in vivo to yield cysteine or oxidation to yield diacetylcystine. The mucolytic activity of acetylcysteine is unaltered by the presence of DNA, and increases with increasing pH. This group probably "opens" disulfide linkages in mucus thereby lowering the viscosity. The mucolytic action of acetylcysteine is related to the sulfhydryl group in the molecule. The latter increases with increasing purulence owing to the presence of cellular debris. The viscosity of pulmonary mucous secretions depends on the concentrations of mucoprotein and, to a lesser extent, deoxyribonucleic acid (DNA). ![]()
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