This review is an update of recent advances in our understanding of
cough suppressants and impairment of
cough. Low-dose oral
morphine has recently been shown to significantly suppress
chronic cough, but the side effect profile of this
opioid may limit its widespread utility. Several studies have demonstrated a dissociation between the efficacy of
antitussives in some metrics of pathologic
cough and their effects on
cough sensitivity to inhaled irritants. The relevance of widely used inhaled irritants in understanding pathologic
cough and its response to
antitussives is questionable. A recent advance in the field is the identification and measurement of an index of sensation related to
cough: the urge to
cough. This measure highlights the potential involvement of suprapontine regions of the brain in the genesis and potential suppression of
cough in the awake human. There are no new studies showing that
mucolytic agents are of value as monotherapies for
chronic cough. However, some of these drugs, presumably because of their
antioxidant activity, may be of use as adjunct
therapies or in selected patient populations. The term dystussia (impairment of
cough) has been coined recently and represents a common and life-threatening problem in patients with neurologic disease. Dystussia is strongly associated with severe
dysphagia and the occurrence of both indicates that the patient has a high risk for aspiration. No pharmacologic treatments ae available for dystussia, but scientists and clinicians with experience in studying
chronic cough are well qualified to develop methodologies to address the problem of impaired
cough.