What drug class is known for decreasing activity in the central nervous system?

The drug class that is known for decreasing activity in the central nervous system is narcotics, often referred to as opioids. These medications work primarily by binding to specific receptors in the brain and spinal cord, effectively reducing the perception of pain and inducing feelings of relaxation and sedation. This central nervous system (CNS) depression can lead to decreased respiratory rate, drowsiness, and, at higher doses, loss of consciousness. Consequently, narcotics are often employed in pain management but must be used with caution due to their potential for addiction and respiratory suppression.

The other drug classes listed function very differently. Decongestants primarily relieve nasal congestion by constricting blood vessels in the nasal passages, leading to increased nasal airflow rather than reducing CNS activity. Diuretics promote the excretion of water and salts from the body, impacting fluid balance and kidney function, but they do not influence CNS activity directly. Cathartics are agents that stimulate bowel movements, facilitating the evacuation of the bowels, and similarly do not have a depressant effect on the central nervous system.