The patient-controlled analgesia (PCA) safety system includes a housing with a hollow compartment. A display and keypad are disposed on one side of the for display of monitoring data and selective commands respectively. An analgesic module and an antidote module are detachably mounted inside the compartment. A control module is disposed inside the housing. A vital signs monitor is connected to the control module to monitor a patient. In the event of abnormal readings due to, e.g., overdose or drug-related complications, the control module can automatically administer an antidote to the analgesia. The control module can also alert a nurse monitor and/or other personnel wirelessly to insure someone is notified of the potential emergency. The PCA safety system can also be provided in a separate safety module having a detachably mounted antidote module.
