Opioids-associated Cough:
Opioids are known to have a central antitussive effect. However, some
opioids, such as alfentanil, fentanyl, and sufentanil, can produce a
brief tussive effect within a few seconds of rapid intravenous bolus
injection in about 50% of patients (especially smokers). This is due to
chemical stimulation of opioid receptors in the smooth muscle of the
trachea, bronchi and bronchioles. It is unlikely that this pulmonary
chemoreflex is mediated by the vagus nerve, as it is not affected by
atropine pretreatment. Instead, pretreatment with an inhaled
β-2-adrenergic agonist significantly reduces the rate of cough
associated with intravenous opioid injection. This opioid-associated
cough is usually self-limiting. It is also related to circulation time
and could serve as a clinical cue for vein-to-brain time or cardiac
output (63).