Addictions Flashcards
What is tolerance?
Reduced responsiveness to a drug caused by previous drug administration
What drugs does tolerance develop in?
Opiods
Ethanol
Barbituates
Benzodiazepines
What are the 2 mechanisms underlying tolerance?
Dispositional tolerance
Pharmacodynamic tolerance
What is dispositional tolerance?
Less drug reaches active site
What are the causes of dispositional tolerance?
Decreased rate of absorption
Drug metabolised faster
Increased rate of excretion
What is pharmacodynamic tolerance?
Drug has less action at active site
What are the causes of pharmacodynamic tolerance?
Down regulation or internalisation of drug receptors
Reduced signalling downstream of receptors
Why is tolerance associated with withdrawal?
Body depends on drug to maintain new “normal” state, and develops into physical dependence to avoid withdrawal effects
What is the reward pathway?
Neurones project from central tegmental area to nucleus accumbent and prefrontal cortex
When VTA neurones stimulates, dopamine released, causing sensation of pleasure
What drugs tap into the reward pathway?
Heroin
Amphetamine
Cocaine
What effects does heroin have on the reward oathway>
Increases firing rate of dopaminergic neurones
What effect do amphetamines have on the reward pathway?
Increase dopamine release
What effect does cocaine have on the reward pathway?
Inhibits dopamine uptake
What effect does interaction with he reward pathway have on drug use?
Produces craving, physical component of addiction
What are the routes by which cocaine can be taken?
Smoking- almost immediate effects
Injecting- 15-30secs
Smorting- 3-5mins
What are the withdrawal effects of cocaine?
Depression Irritability Agitation Craving Hyperphagia Hypersomnia
What ar the routes of administration of amphetamines?
Sniffed
Swallowed
Injected
What are the types of opiates?
Opium Morphine Heroin Methadone Codeine and dyhydrocodeine
What are the routes of administration of heroin?
SNorting
Smoking
Injecting
What are the side effects of opiates?
Initial- N&V, headache
Medium- phlebitis, anorexia, constipation
Long term- tolerance, withdrawal, social and health problems
What are the signs and symptoms of opiate withdrawal syndrome?
Craving Insomnia Yawning Muscle pain and cramps Increased salivary, nasal and lacrimal secretions Dilated pupils Piloerection
What are the negative effects of steroids?
Acne, stretch marks, baldness Feminisation in males- hypogonadism, gynaecomastia Virilisation in females- hirsutism, deep voice, clitoral enlargement, menstrual irregularities, hair thinning Increased cholesterol and hypertenson Growth deficits Liver disease Irritability and anger Hypomania and mania
What are the withdrawal symptoms of steroids?
Depression and suicidality