Central nervous system stimulants selectively excite the central nervous system to enhance its function. These drugs can be used when the central nervous system is in a depressed, low-functioning, or disordered state.
Long-term use of these drugs can cause adverse effects such as loss of appetite and insomnia and may trigger or worsen psychiatric symptoms like depression, suicidal thoughts, hostility, mental abnormalities, and mania. These drugs mainly include wakefulness-promoting agents, psychostimulants, and cognitive enhancers. Representative drugs include amphetamines and methylphenidate.
Central cough suppressants work by directly inhibiting the medullary cough center. Morphine alkaloids and their derivatives, such as codeine, pholcodine, and hydrocodone, are addictive and are also known as dependence- or addiction-forming cough suppressants. Long-term use can lead to tolerance and addiction.