Respiratory Depression	A dangerous effect of opioid toxicity is slowed or stopped breathing due to suppression of the brainstem's respiratory centers, leading to fatal outcomes if untreated.
Pinpoint Pupils (Miosis)	Constricted pupils are a hallmark of opioid intoxication, although in severe cases, anoxia may lead to fixed and dilated pupils.
Unconsciousness or Unresponsiveness	Patients experiencing an overdose often exhibit deep sedation or unconsciousness, making timely intervention critical.