How can just one or two pills kill a person? Prescription drugs affect the central nervous system (CNS), which is made up of the brain and the spinal cord. Some prescription drugs slow down, or depress the CNS, while others speed up, or stimulate the CNS. When a person takes a prescription drug they give up some control of their body to the drug. Prescription drug overdoses can result in serious brain damage, coma or death. Every prescription drug behaves differently in each person's body and central nervous system, interacting with their unique body chemistry and underlying health conditions. What might not affect one person, may kill or harm another. Drugs come in different strengths—some, in particular OxyContin and methadone, come in strengths strong enough to kill someone in one dose. Opioids are the most common type of prescription drug, resulting in death from overdose. The cause of death in cases of opioid overdose is almost always respiratory failure. Usually, the person will get weak from lack of oxygen, lose consciousness, stop breathing and die. If you are the one experiencing an overdose, you will not be aware that you are in trouble—your only hope is for someone around you to recognize that something is wrong. One of the key factors in recognizing an overdose is paying attention to how a person is breathing.