Presentation on theme: "Medicines and drugs Stimulants. stimulants What are stimulants? Examples? What medical uses do they have?"— Presentation transcript:
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
amphetamines 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 termlong 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/letha l 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 effectslong 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