Transcript stimulants
CHEMISTRY MEDICINES AND DRUGS STIMULANTS Stimulants are drugs that > stimulate the brain and the central nervous system > increase the state of mental alertness > decrease appetite A) Amphetamines B) Caffeine C) Nicotine Adrenaline (epinephrine) is a natural stimulant produced in the adrenal gland. > it is released when in stress or fear > it controls - heart/breathing rate - pupil dilation - sweating AMPHETAMINES Amphetamines are chemically related to adrenaline. • They both derive from phenylethylamine. • They are sympathomimetic drugs which mimic the effect of stimulation on the nervous system by increasing the levels of dopamine. • Amphetamines were initially used to treat narcolepsy and in WW II were used by soldiers to combat fatigue. • Later during the 50’s and 60’s they were used as slimming pills. • Regular use can lead to both tolerance & dependence. • Short-term effects: - increase in heart rate and breathing - insomnia - dilation of the pupils - decrease in appetite - possible fatigue and depression • Long-term effects: - weight loss - constipation - emotional instability - dependence • Phenylethylamine (love molecule) - “high” feeling of lovers - also found in chocolate Dopamine Transmits to neurons signals of - joy - happiness - excitement Amphetamine - stimulant - suppresses appetite - treats narcolepsy Methamphetamine (“speed”) - potent stimulant - very addictive - severe withdrawal symptoms - “meth mouth” Ecstasy - potent stimulant - designer drug - can be fatal - neurotoxic CAFFEINE • It is the most widely used stimulant in the world. It is present in coffee, tea, chocolate and cola drinks and is also found in some pain killers or other medicines. • People that consuming 400 mg of caffeine a day may have dependence & physical side effects. • Like nicotine, morphine, codeine and cocaine, caffeine is also an alkaloid. • Alkaloids are nitrogen-containing compounds of plant origin containing heterocyclic rings and a tertiary amine group. • Theobromine has a similar structure to caffeine, which is also found in chocolate. (It does not contain bromine!) • caffeine theobromine Effects at low doses: - respiratory stimulant - weak diuretic - enhances concentration and alertness - reduces migraines (constriction of blood vessels) • Effects at high doses: - anxiety - irritability - sleeplessness • NICOTINE One third of the world’s population is addicted to smoking because tobacco contains nicotine • Nicotine produces psychological and/or physical dependence • Nicotine builds up tolerance • Stopping smoking can produce temporary symptoms like a craving for tobacco, nausea, weight gain, insomnia, irritability and depression • Short-term effects: - stimulates nervous system - increases heart rate and blood pressure - increases concentration - constricts blood vessels - stresses heart - reduces urine output • Long-term effects: - increases risk of heart disease coronary thrombosis - inhibits ability of blood to carry oxygen (CO) - excess acidity > peptic ulcers - mouth/lung cancer - adverse effects on pregnancy Both compounds are heterocyclic with one or more carbon atoms in the ring replaced by nitrogen atoms. They both contain a tertiary amine group caffeine nicotine