Medicines and drugs

Stimulants

stimulants

• What are stimulants?

• Examples?

• What medical uses do they have?

stimulants

• nicotine, caffeine, amphetamines

• the intention of these drugs is to have similar effects to adrenaline (or epinephrine) which is a natural stimulant.

• amphetamines (synthetic) can do this because they have similar structures to adrenaline.

stimulants

• affect central nervous system; act on the level of neurotransmitters which are chemicals that acts as messengers and stimulate pathways which …

• …increases activity of the brain

• largely opposite to depressants which decrease activity in the nervous system

• group of drugs which mimic the effect of adrenaline

• classified as symphatomimetic drug as it stimulates the symphatetic nervous system

• adrenaline or epinephrine = hormone released in times of stress e.g. pain, cold, fear, …

• response to increased adrenaline in the body:• increased heart beat/blood pressure• Increased blood flow to brain and muscles• Increased air flow to lungs• Increased mental alertness

physiological effects

short term long term

increased brain activity increased heart rate, increased blood pressure, increased breathing rate increased air flow in air

passages shakes increased alertness and

concentration sleeplessness decreased appetite

increased risk of heart disease

increased blood pressure coronary thrombosis stomach ulcers. tolerance: increasing amounts cause

damage/death/overdose/lethal dose

compare

• Common: both amphetamines and epinephrine have a phenyl-ethyl-amine chain which consists of a benzene ring linked to an amine group by a carbon chain (ethyl).

• Different: functional groups• amphetamines:

• primary amine

• epinephrine:• 3 hydroxyl groups• secondary amine

nicotine

• A nicotine molecule contains the following functional groups: a tertiary amine, benzene ring structures with nitrogen atoms in them (=heterocyclic rings).

• Nicotine increases levels of adrenaline in the brain

physiological effects nicotine

short term effects long term effects

increased heart rate

increased blood pressure

reduced urine output

increased concentration

increased risk of cancer or stroke heart disease / thrombosis stomach ulcers emphysema bronchitis shortage of breath coughing bad breath yellowing of teeth or fingers adverse effect on pregnancy addiction to tobacco reduction in capacity of blood to carry

oxygen; withdrawal symptoms / weight gain (on

quitting);

caffeine• Caffeine is a

psychoactive stimulant (=acts on CNS). When consumed in large amounts it can cause anxiety, irritability and sleeplessness. It is a weak diuretic i.e. causes the body to lose more water than it takes in.

• Its structure is similar to nicotine.

structure of caffeine

• benzene rings containing both carbon and nitrogen atoms (heterocyclic rings)

• tertiary amine group

• two amide groups (- N – C = O)

caffeine

consumption in small amounts

large amounts

• increased mental alertness• greater ability to concentrate•diuretic; dehydration

•can cause anxiety, irritability, nausea•dependence