Therapeutics 2 Flashcards
why do we need to know about neurotransmitters?
common
what happens when a nerve transmits its signal down an axon ?
what do we find across the membrane of cells ?
transmembrane potential
what does the membrane consist of?
phospholipid bilayer - impermeable to water
pumps - pumps charged ions out of cell or into
channels - most of the time are closed but can open when they’re supposed to
what will all cells have along their membrane ?
pumps that will pump Na out of cell and K into cell
- so there’s a net positive charge outside the cell and net negative charge inside the cell
- so if we stick an electrode into cell we can record a transmembrane potential
when do the channels in a cell open ?
we there’s a change in voltage around them
what is the resting membrane potential ?
change in potential - this allows signals to pass along cell very quickly
how do we integrate nerve signal?
neurotransmitters which are released from its presynaptic terminal
list the different types of synapses
what are neurotransmitters?
give an eg of a neuromuscular junction
what does the sympathetic system promote?
fight or flight, high bp, increase heart rate
diverts blood from gut to brain and heart and kidneys
what is the principle NT used in sympathetic nervous system ?
noradrenaline - this is why when we use LA with this NT pt feels palpitations
what are sympathomimetics?
drugs that mimic action of SNS
give eg of direct sympathomimetics?
what do we use phenylephrine for?
nasal decongestants
what do we use albutamol for ?
bronchodilator
list some adrenoceptor antagonists ?
what is propranolol?
beta blocker used for anxiety and high BP
what is tamsulosin used for?
prostatic hyperplasia - men that have prostatism
list some indirect sympathomimetics?
what is amphetamine used for ?
stimulates NE which increases BP, HR, excerise and muscle tone
what does cocaine do?
inhibits NE uptake at synapse and hangs around longer which increases HR BP
where else can NT be found other than peripheral nervous system ?
CNS
list all the ways NT coordinate with CNS ?
list some NT found in CNS
what is GABAs role ?
inhibitory - anxiolytic (anxiety reducing), hypnotic effects (sleep inducing)
what is GABA used in?
status epilepticus and anxiety
what is benzodiazepine?
- The benzodiazepine receptor is part of the GABA channel. Binding with benzodiazepines (BDZ) enhances the effect of GABA
- Benzodiazepines have no effect in the absence of GABA. The presence of GABA is essential for the action of benzodiazepines
What is the role of flumazenil in the context of benzodiazepine receptors?
Flumazenil inhibits the effect of benzodiazepines by binding to their receptors. It is used as an antidote to reverse the effects of benzodiazepine overdose or excessive sedation.
which opioid analgesics mimic endogenous peptides
- Endorphins
- Dynorphins
- Enkephalins
modulate our perception of pain, feeling of wellbeing, respiratory effort and alertness
what are opiates used for?
painkillers
sedation - to the point where u stop breathing - problem with addicts and elderly ppl who are exercising loads of pain
list some strong opioids ?
- Morphine
- Diamorphine (heroin)
- Methadone
- Fentanyl
- Tramadol
- Pethidine
- Oxycodone
list some moderate/ weak opiates
codiene
dihydrocodiene
both are metabolised to morphine to work
why do opioid analgesics work?
there are opioid receptors in brain, spinal chord and GIT
what effects do opioid analgesics produce?
analgesic
resp depression
euphoria
sedation
nausea vomiting
constipation
list some recreational drugs
alcohol
nicotine
stimulants
opioids
how does alcohol work? effects? addictive?
influences Ca influx in central neurons and that depresses the release of NT stopping communication between nerves - leads to relaxation and loss of consciousness which can lead to disinhibition - impaired judgment - loads of alcohol= wernicke Korsakoff which is due to thiamine deficiency
- addictive -
how does nicotine work? effects? addictive?
most common, affects ACh, GABA, dopamine and multiple systems such as parasympathetic and sympathetic - toxicity is due to the products from nicotine such as tar, carcinogens etc - addictive
how do stimulants eg. amphetamines, cocaine and ecstasy work? effects? addictive?
act on dopamine and NE pathways- euphoria, increased energy, increased muscle tone - hypertension and tachycardia side effects
how do opioids work? eg. heroin and methadone
endorphin receptors in spinal cord and brain - analgesia, euphoria, sedation - resp, depression, vomiting, constipation side effects- addictive
how do benzodiazepines eg. diazepam and midazolan work? effects? addictive?
enhance GABA influence in brain - anxiolytic, hypnotic - respiratory depression side effect- addictive only prescribe for couple of days
how do hallucinogens eg. LSD work? effects? addictive ?
inhibit 5HT pathways in brain - altered perception- panic delusion, bad trip side effects - not addictive
how does cannabis work eg. cannabis leaf and resin? effects? addictive ?
CB1 receptors in brain - euphoria, relaxation- psychotic effects paranoid - not addictive
how does Nitrous oxide work? effects? addictive?
depresses neurones in RAS - analgesia - euphoria sedation - not addictive
how do solvents eg. glue and petrol work?
central depression of NT release - distinction and relaxation - impaired judgement risk taking behaviour - addictive
what are the different ways drug misuse, dependance and addiction can affect us?
including :
1. Nicotine
2. Alcohol
3. Prescription medication
intoxication, at risk use, dependence, withdrawal, longer term consequences
what is intoxication?
impaired judgement, respiratory depression and loss of protective reflexes eg. if u are under influence of heroin and are going to vomit cough reflexes may be suppressed and u will inhale vomit
what are the at risk uses?
at risk of physical/mental harm eg. alcohol >14u/wk
what is harmful use ?
continued substance use despite evidence of physical/mental or social harm
what is dependance ?
addiction physical/ psychological problems if unable to continue taking substance needs more or more frequently
what is withdrawal?
physical/ psychological effects eg insomnia, agitation sympathetic stimulation (tachycardia sweating)
what are long term complications?
long term psychiatric
wernicke - Korsakoff syndrome in alcohol abuse
lung cancer in smoking
what are the mechanisms underlying pharmacological tolerance and dependence?
what are endogenous antagonist ?
block action of drugs
what are the roles of induction enzyme s?
Increased production of enzymes that clear the active drug.
whats the role of down regulation of receptors ?
Reduction in the number of receptors, decreasing the drug’s activity.
what NT do we deplete ?
GABA NE 5HT
What causes synaptic changes in the context of drug dependence?
Synaptic changes are caused by the presence of the drug, and the nervous system adapts to its continuous presence, leading to alterations in synaptic function.
what is dependance syndrome according to Edwards 1976?
1.Primacy of drug seeking behaviour: “do you need a drink first thing in the morning”.
2. Narrowing of drug-taking repertoire: concentrate on a particular drug
3. Increased tolerance: need increased doses to achieve effects.
- smoking heroine to IV
- cocaine to crack
4. Loss of control - lose family
5. Drug use to avoid withdrawal
6. Continued use despite negative consequences
7. Rapid relapse following period of abstinence
what can alcohol abuse cause?
- Alcoholic liver disease, cirrhosis - portal hypertension
- GIT: gastric ulcer, oesophageal varices
- Cancer: head and neck, GI, liver
- CVS: hypertension, IHD
- Neurological
- Wernicke-Korsakoff syndrome - looks like dementia - confusion, memory loss - Thiamine deficiency (Vit B1)
- Poor diet, reduced absorption due to changes in GIT mucosa, impaired liver storage of vitamin b1
- Neuropathy, confusion, psychosis
- Manage with Vit B supplement (pabrinex= vit B and C)
what is cage?
- Have you ever felt you should CUT back on your drinking?
- Has anyone ever ANNOYED you by criticizing your drinking?
- Do you ever feel GUILTY about your drinking?
- Have you even had a drink in the morning as an EYE OPENER
- More than 2 positive answers, signpost to GP for further assessment.
