Patients taking opioid drugs may feel sleepy but could also experience a slower rate of breathing and heart rate. This slow heart and respiratory rate could lead to severe complications or even death. The amount of opioids that could cause overdoses varies, depending on: The type and strength of the opioid drug; The patient’s weight, age, and biochemistry. Some people may also suffer opioid overdoses because of their interactions with other medications that they are taking.