Embodiments provide a continuous monitor of a patient's oxygenation and/or respiration coupled to a device configured to stimulate the patient's respiratory drive and/or summon medical assistance. In embodiments, there are provided systems, devices, and methods to assist in preventing patients from overdosing themselves with narcotics post-surgery. In embodiments, an apnea prevention device (APD) may utilize a commercially available pulse oximeter and/or a respiratory monitor to continuously monitor a patient's level of oxygenation/respiration. Should a patient develop respiratory depression or apnea and begin to desaturate, an APD may, using a proprietary method, trigger a sequence of staged responses to reverse worsening hypoxia.