Nervous systems and drugs Flashcards
Examples of excitatory neurotransmitters?
noradrenaline dopamine serotonin acetylcholine glutamate
examples of inhibitory neurotransmitters
GABA
glycine
types of drugs that mainly act on nervous system
- anaesthetics
- anxiolytic/hypnotic
- neuromusculars blocking drugs
- antidepressant drugs
- antiparkinsonian
- anticolvusants
how are anaesthetics administered?
Intravenously
inhalation
why are anaesthetics?
to promote analgesia, unconciousness, amnesia, loss of reflexes
how do anaesthetics work?
they promote insensitivity via crossing blood-brain barrier (as they are lipid soluble). they can affect neurone excitability via binding to receptors and can affect ion channels
side effects of anaesthetics
nausea/cvomiting
shallow/rapid rbeathing
crosses placenta
loss of temperature control
what are the 4 stages of anaesthetics?
stage 1- analgesia
stage 2- excitement
stage 3- surgical anaesthesia via skeletal relaxation and loss of reflexes
stage 4- medullary paralysis> loss of respiratory/ vasomotor control
what the types of general anaesthetics?
barbiturates
gases
non-barbiturate
volatile liquids
what is nitrous oxide use for?
for maintaining anaesthesia with oxygen
its a potent analgesic
other examples of inhaled anaesthetics?
isoflurane
desflurane
sevoflurane
what the commonly used intravenously administered drugs?
propofol-non barbiturate
thiopental- barbiturate
advantages of propofol
rapid action and rapid recovery
disadvantages of propofol?
may cause convulsions
advantages of thiopental?
useful for brief procedures
disadvantages of thiopental?
rapid awakening
other examples of anaesthetics?
etomidate- it causes no hangover effect and less hypotension but causes muscle movements and suppresses the adrenocortical function
ketamine- used to shock patients. it increases blood pressure and heart rate and causes bad hallucinations and bad dreams
what are anxiolytics/hypnotics drugs?
benxodiazepines
what does increasing doses of benzodiazepines do?
anxiety> sedation> hypnosis
examples of hypnotic drugs
midazolam
temazepam
diazepam
advantages of hypnotic drugs?
causes amnesia
does no cause excessive sedation in low doses
disadvantages of hypnotic drugs?
no analgesic effect causes constipation/hypotension may lead to dependence causes respiratory depression crosses placenta it interacts with alcohol
What are neuromuscular blocking drugs?
muscle relaxantts
what do neuromuscular blocking drugs do?
they block transmission in motor nerves
causes deep anaesthesia
relaxes vocal cords to allow endoscopy
disadvantage of neuromuscular drugs?
it prolongs muscle paralysis/pain
causes brochospasm due to histamine release
what are non-depolarising drugs?
acetylecholine antagonist
what are depolarising drugs?
acetylecholine agonist
what to use to reverse effects of non-depolarising drugs?
administer drugs that inhibit acetylcholinesterase e.g. neostigmine
what is pseudocholinesterase?
it metabolises suxamethonium (acetylcholine agonist)
what do narcotic analgesics do?
they act on the opioid receptors in CNS to relieve pain
examples of narcotic analgesics
fentanyl
alfentanil
remifentanil
morphine
disadvantages of narcotics?
causes nausea/vomiting
reduces breathing rate
can be addictive
what are local anaesthetics use for?
for minor procedures for analgesia and paralysis
mechanism of anaesthetics
block transmission of nerve impulses from nociceptors (pain receptors) via blocking entry of sodium ions through voltages gated channels
common methods of administration of anaesthetics?
epidural
intradermal and topical to relieve superficial pain/irritations
commonly used anaesthetics
lidocaine- use in dentak surgery and stud 100 (treatment for premature ejaculation)
prilocaine- in creams
adverse effects of anaesthetics?
abnormal heart beat
convulsions
cardiorespiratory arrest
hypersentivity
what are vasoconstrictors use for?
prolong drug action and enhance potency
reduces toxicity
reduces blood loss
examples of vasoconstrictors
adrenaline
felypressin
what do antidepressants do?
increase excitatory neurotransmitters levels in brain
what do antiparkinsonians do?
increase levels of dopamine
what do anticonvulsants do?
treatment for epilepsy via reducing conduction of excitatory nerve impulses
or/and increases GABA activity
3 types of antidepressants?
tricyclic antidepressants (TCAs)
Selective serotonin re-uptake inhibitors (SSRIs)
Monoamine oxidase inhibitor (MAOIs)
tricyclic antidepressants and selective serotonin reuptake inhibitors mechanism?
blocks reuptake of receptor
what do monoamine oxidase inhibitor do?
blocks enzymes from breaking down the neurotransmitters
