Emergency Medical Technician (EMT) Basic Certification 2025 – 400 Free Practice Questions to Pass the Exam

Depressant drugs, such as alcohol, benzodiazepines, and opioids, generally act by slowing down various functions in the central nervous system. One significant effect of these substances on the cardiovascular system is a decrease in heart rate, often termed bradycardia. This occurs because depressants can reduce the excitability of neurons, leading to a slower conduction of electrical impulses that regulate heart function.

Decreased heart rate can be clinically relevant because it may lead to inadequate blood flow to vital organs, especially in overdose situations. This effect contrasts with stimulants, which typically increase heart rate and blood pressure due to their excitatory nature. Similarly, the other answer choices relate to cardiovascular responses that are not common with depressants; stimulants increase heart rate and blood pressure, while irregular heartbeat can result from various factors, including electrolyte imbalances or other types of drug overdose. Thus, the decrease in heart rate is distinctly associated with the action of depressant drugs on the cardiovascular system.