Drugs that affect the Central Nervous System

Drugs that affect the Central Nervous System (CNS)

Two categories of drugs fall under CNS. They are CNS stimulants and CNS depressants.

CNS stimulants are drugs that increase behavioural activity, thought processes, and alertness or elevate the mood of an individual. Amphetamines, caffeine, nicotine and cocaine are examples of these drugs.

Amphetamines are structurally similar to neurotransmitter norepinephrine. It increases both the heart and respiratory rates, reduce fatigue and diminish hunger by raising the glucose level in the blood. It was once used for weight control but has diminished due to its side effects.

Caffeine is the most widely used non-prescriptive CNS stimulant. It increases heartbeat and basal metabolic rate, promotes secretion of stomach acid, and steps up production of urine. The overall effect makes an individual a feeling of being wide-awake and able to focus on mental or manual tasks. However, excessive consumption of caffeine may lead to restlessness, disturbed sleep, stomach upset and diarrhoea. In fact, our daily beverages such as coffee, tea, cola drinks, etc contained a substantial amount of caffeine and it has a mild addicting effect for people who like to drink these beverages.

Nicotine is the next most widely used CNS stimulant in our society. It is originated from tobacco leaves and is found in both smoking cigarettes and chewing tobacco. Nicotine is distributed rapidly th h increase mental awareness and decrease fatigue is cocaine, a chemical substance extracted from the cocoa plant. The stimulating effect is short and followed by a period of deep depression. Unfortunately, cocaine has become a dominant chemical in the illegal drug market. Due to its rapid absorption through the mucous membrane of the nose and throat, it is generally “sniffed” by users. This causes muscle relaxation of the bronchial airways of the lungs and constriction of the nasal blood vessels, making breathing easier. When the drugs wear off, the bronchial muscle contract and the blood vessel relax, causing regular users nasal stuffiness and tender, bleeding nasal membranes, urging for more drug, delaying but intensifying the symptoms. This eventually leads to a deterioration of the mucous linings, chronic runny nose and holes in the cartilage.

CNS depressants are directly opposite of CNS stimulants which decrease behavioural activity, alertness and thought processes. They are often regarded as sedative-hypnotic compounds (drugs that cause relaxation), which resemble general anesthetics (GA) in inducing sleep but differ from GA in being solid or liquid (rather than gaseous) and in having a longer action than GA. Two types of CNS depressants are barbiturates and alcohol.