With over 75,000 attributed deaths in 2020, opioid overdose is now the leading cause of death amongst Americans under the age of 50. With record-breaking increases in fatalities for the past 10 years, fentanyl in particular has many experts worried about the future of the opioid epidemic. To reverse opioid overdose there exists a drug called Naloxone, an opioid antagonist that completely restores the subject’s vitality within minutes. As the US opioid epidemic is surging by the increase of synthetic opioid-related overdoses, current methods of Naloxone administration are unsuccessful in suppressing the rise. One large obstacle in the rate of success for Naloxone is related to the fact that opioid users are not able to administer the antagonist to themselves due to their overdosing symptoms, which includes unconsciousness. Therefore, to save a life with Naloxone, one has to rely on a bystander that is present during the overdose, recognizes it, possesses Naloxone, and is able to administer it in time. The rising death toll of opioid overdose reveals that one of these conditions are often not met. This thesis presents a fully implantable device that is capable of autonomously detecting and treating opioid overdose to provide an alternative solution that takes the said bystander out of the equation. To achieve this, three different sensors (an Inertial Measurement Unit (IMU), Electrocardiography (ECG), and Photoplethysmography (PPG) sensor) are used for the monitoring of heart rate and respiratory rate. These vital sings are continuously fed into an advanced decision-making system that is capable of detecting opioid overdose within 81 seconds. Once detected, instructions are sent to a novel drug delivery pump that is capable of delivering high volumes of Naloxone within only 3.25 seconds, while outperforming similar technologies in terms of energy efficiency. The proposed subcutaneous implantable device can be refilled through a refill port, be wirelessly charged, and has a battery capacity that lasts up to 78 days. It is concluded that the proposed closed-loop drug delivery system is a feasible and effective autonomous tool that could complement existing Naloxone administration solutions in the ongoing fight against the opioid epidemic.