22 - Systemic Drugs II - CNS Flashcards
what CNS drugs are used for mental health
- antidepressants (anti-cholonergic effects, pupilary dilation, impact on accomodation and blurred vision)
- anxiolytics and hypnotics (sedatives)
- antipsychotics
- antiepileptics
who should anti depressants be considered for
- past history of moderate/severe depression
- subthreshold depressive symptoms present for long time
- suqbthreshold depressive symptoms or mild depression that persist after other interventions
first line choice of drug for prescribing in depression
- SSRI
as effective as TCAs and much safer in overdose
depression is associated with low levels of?
monoamine neutrotransmitters in brain
name some of the neutotransmitters
- serotonin 5HT
- noradrenalin
- dopamine
what should the drugs do to the levels of these monoamines
maintain the levels
low = depression
selective serotonin re uptake inhibitors (SSRI)
They restore the levels of 5HT in the synaptic cleft by binding at the 5HT reuptake transporter -preventing the reuptake and subsequent degradation of 5HT
simply how does the drug SSRI work
by blocking the receptor and increasing the levels of 5HT
examples of SSRI
- citalopram
- escitalopram
- fluoxetine
- paroxetine
tricylic anti- depressants TCAs
- TCA bind to 5HT and noradrenalin re-uptake transporters: prevents re-uptake of these monoamines from the synaptic cleft
- leads to accumulation of 5HT and noradrenalin in synaptic cleft, conc returns to normal range
what is the half life of a TCA
long, allows single daily dose regime, given at night when sedative effect might be helpful
examples of TCA
- amitriptyline
- clomipramine
- imipramine
serotonin and noradrenaline reuptake inhibitors
Next generation of anti depressant drugs
Similar to tricyclics
-serotonin-norepinephrine reuptake inhibitors? work by
block re-uptake
increasing concentration of these neurotransmitters at synaptic cleft
examples of serotonin and noradrenaline reuptake inhibitors
- venlafaxine
- duloxetine
Monoamine oxidase inhibitors (MAOI’s)
- treatment resistant depression - use limited due to dietry restrictions
examples of MAOI
Phenelzine (Nardil), Isocarboxazid. Moclobemide (Manerix)
monoamine oxidase A - What is it and what does it do
an enzyme involved in metabolism of the monoamines 5-HT and noradrenalin
- converts monoamines into their corresponding carboxylic acid
-MAOI inhibit monoamine degradation and result in greater stores being available for release
what are hypnotics used for
short-term managment of insomnia
- tolerance occurs in 1-3 nights
what are anxiolotyics for
short term relief of anxiety that is severtr
what to use for chronic anxiety (>4 weeks)
antidepressant
what are some hypnotics (sleeping tabs)
benzodiapenes
-short half life
nitrazepam, flurazepam
non-benzodiazepene hypnotics
- zomplicone
what are some anxiolytics
benzodiapenes with a long half life
- diazepam
- lorazepam
- oxazepam
muscle relaxers
more effective as longer half life
how do benzodiazepines work
- enhnace the action of GABA at GABA-A receptors when they bind
- makes GABA more effective at calming down nerve activity
antipsychotics are also known as
neuroleptics or major tranquillisers
what are antipsychotics used for
- schizophrenia
- mania
- psychotic depression
useful for short term sedation in aggression/agitation
what effects do antipsychotics have in schizophrenia
prophylactic - prevents something from happening
what type of antipsychotics are there
typical and atypical
where do typical (conventional) antipsychotics act
- dopamine receptors
what are the side effects of typical antipsychotics
- sedation
- extrapyramidial effects
- anticholinergic effects
examples of typical antipsychotics
-Phenothiazines e.g. chlorpromazine
-Thioxanthenes e.g.flupentixol
-Butyrophenones e.g. haloperidol
where do atypical antipsychotics act on
- other receptors as well as dopamine
- less likely to cause movement disorders as a side effect as more modern
examples of atypical antipsychotics
-Amisulpride
-Clozapine
-Olanzapine
-Quetiapine
-Risperidone
how is psychosis induced
increased levels of dopamine activity
how do most antipsychotic drugs work
- block post synaptic dopamine receptos
(D2)
what are bipolar drugs used for
to control acute attacks and also to prevent their recurrence
which drugs are used for bipolar disorder
Acute attack
-Benzodiazepines
-Antipsychotics
Prophylaxis
-Lithium (Priadel)
what is the objective treatment of antiepilectics
prevent recurrence of epileptiform events (seizures)
what occurs in a epileptiform event
a sudden, excessive depolarisation of cerebral neurones which may remain localised (focal epilepsy) or spread (generalised epilepsy)
what do anti-epileptic agents prevent
depolarisation of neurones
-inhibition of excitatory neurotransmitters
-direct membrane stabilisation
-stimulation of inhibitory neurotransmittersq
what are common anti-epileptics
-Carbamazepine
-Lamotrigine
-Sodium Valproate )
Antiepileptics with significant ocular adverse reactions
-Vigabatrin
-Topiramate
