Which effect of morphine can be attenuated by atropine?
The miotic effect of morphine is caused by activation of the Edinger-Westphal nucleus of the third cranial nerve, which activates the parasympathetic outflow to the iris sphincter muscle, causing pupillary constriction. This effect can be antagonized by muscarinic antagonists such as atropine. Atropine has no effect on the other central nervous system or peripheral actions of opiates. Ref: KD Tripathi 8th ed.
Analgesia
Respiratory depression
Antitussive effect
Miosis
Autacoids