Addictions Psychiatry Flashcards
what are the two mechanisms of addiction
tolerance
reward centre
what is tolerance
defined as reduced responsiveness to a drug caused by previous administration
develops in response to many types of drugs eg opioids
what are the mechanisms of tolerance
less drug absorbed
drug metabolised faster
more drug excreted-less drug reaches active site
what is dispositional tolerance
less drug reaches the active site
what is pharmacodymic tolerance
site of action is less affected by the drug q
what is dependence
have to keep taking the drug to maintain equilibrium
what is the withdrawal phenomena
tolerance and dependence are closely linked
the withdraw is the reverse of the acute effect
what is the reward centre
nuerons from ventral tegemental area in the nucleus accumbens and prefrontal Cortez
dopamine is released
describe cocaine and its effects
potent natural stimulant cocrain hydrochloride is snorted or injected crack is smoked stimulant increased energy and alter ness increased confidence lessens appetite withdrawal-depression, irritability, agitation
how are reward centres used by drugs
heroin increases firing rate of dopaminergic neutrons
cocaine stops uptake of dopamine
describe amphetamine
similar to cocaine
can cause seizures in chronic use
what are examples of opioats
opium morphine diamorphine methadone codeine
describe heroin
snorting, smoking or infecting pupil constriction available as diamorphine bradycardia hypotension
what is the effect of opiates
intense but transient feeling of pleasure
a rush
what are the side effects of opiates
headache and nausea
anorexia , constripation
tolerance and withdrawl
