Methods for detecting enhanced risk of opioid-induced respiratory dysfunction in patients with normal levels of oxygen saturation. The method may comprise: (1) assaying blood of the patient for a normal level of oxygen saturation； (2) measuring the patient's respiration rate at rest for a normal rate； and (3) correlating the normal level of oxygen saturation and the normal rate of respiration with enhanced risk of opioid-induced respiratory dysfunction if: (a) the patient is at an altitude of about 1000 feet above sea level or greater； or (b) the patient's oxygen saturation level is normal but no greater than about 95%； or (c) the patient received prior dosing with intravenous opioid and is converted to dosing with an oral opioid. The method may further comprise administering opioids to a patient after detecting whether there is an enhanced risk of opioid-induced respiratory dysfunction.
