Drugs in Psychiatry Flashcards
ADRs of lithium?
nausea and vomiting, abdo pain
weight gain
renal impairment
impaired thyroid function-hypothyroidism, enlarged thyroid
metallic taste in mouth
teratogenic
fine tremor, coarse tremor suggests lithium toxicity
caution with lithium in renal failure?
must reduce dose or may have to stop as renally excreted so risk of toxic ADRs
what psychotropic drugs may cause discontinuation syndrome?
antidepressants-espec. SA e.g. venlafaxine (SNRI), and paroxetine (SSRI)
symtoms of anxiety, agitation, nausea and vomiting, insomnia, and sensation of body electricity e.g. ‘brain zaps’-electric shock like experiences.
why should an antidepressant alone NOT be prescribed in bipolar?
can induce mania
can only be given alongside an antipsychotic or mood stabiliser
only 1 recommended by NICE?-SSRI?
what must be considered in all patients who develop drowsiness, confusion or convulsions whilst taking an antidepressant?
hyponatraemia, possible result of SIADH-hyponatraemia would be in the context of euvolaemia and urine osmolality more than 500mosmol/kg
been reported more frequently with SSRIs
TCA side effects?
tachycardia prolonged QT hypotension fine tremor anticholinergic: dry mouth, urinary retention, dry eyes, constipation weight gain lowered seizure threshold cholestatic jaundice allergic skin rashes
indications for pregabalin in psychiatry?
generalised anxiety disorder
blocks calcium ion channels
use of memantine?
tment of adult pts with moderate to severe AD
targets glutaminergic neurotransmission, antagonist of NMDA receptors
risperidone class?
atypical antipsychotic
Mood stabilisers that can be used in bipolar?
Lithium
Sodium valproate
Lamotrigine
Carbamazepine
Risks of BZD use in elderly?
Higher falls risk
Disturbed sleep with sedation effects increasing sleep during the daytime
Increased risk of toxicity causing resp depression due to altered pharmacokinetics
Why is there a risk of EP side effects with antipsychotics?
Anti dopamine on substantia nigra and so produce a Parkinsonian like picture with rigidity, bradykinesia, tremor, and postural hypotension.
What is mirtazapine and what is its MOA?
Other antidepressant medication-NASSA-noradrenergic and specific serotonergic antidepressant
Centrally acting presynaptic alpha 2 antagonist, which increases noradrenergic and serotonergic neurotransmission by increasing their release into the synaptic cleft. Weak NA reuptake inhibitor, also antihistamine-latter properties responsible for sedative effects.
Can be combined with SSRIs/SNRIs
ADRs-weight gain, increased appetite, sedation
Psychotropic drugs especially assoc. with withdrawal syndrome?
BZDs
symptoms may include autonomic disturbances e.g. sweating, tremor, disturbed sleep, impaired concentration, depression, pessimistic thoughts.
How does the efficacy of antidepressants differ depending on depression severity?
Greater efficacy the more severe the depression.
Onset of antidepressant action?
3 to 6 weeks for clinical effect to be noted by pt so must advise patients that benefit will not be noted straight away.
BUT usually begin working in 2-3 DAYS
Serotonin syndrome may occur as a result of the use of antidepressants. What is its classical presentation triad?
Autonomic hyperactivity e.g. Tremor
Neuromuscular abnormality e.g. Akathisia
Mental status changes
Syndrome may be noted with antidepressant combinations, recent change in drug or increase in dose or starting new drug.
symptoms usually within 6 hrs of taking provoking drug, and tremor, akathisia and diarrhoea are early features.
Monitoring required with venlafaxine?
Regular BP checks and ECGs as risks of HTN and hypotension.
Why is mirtazapine prescribed at night?
Is associated with dizziness and postural hypotension.
Risk with BZD overdose?
Respiratory depression
How is BZD overdose reversed?
IV flumazenil 500 micrograms
What investigation must be performed before starting acetylcholinesterase inhibitor Alzheimer’s disease medication?
ECG as can cause bradycardia
contraindicated if HR less than 50
must monitor HR
MOA of TCAs
Inhibit re uptake of NA and serotonin, and have anticholinergic, and histamine and adrenergic actions.
Which SSRIs are associated with prolonged QTc?
Citalopram and escitalopram
Duration of treatment with antidepressants following symptom remission?
At least 6 months if 1 episode
If 2 or more within 5 years treat for at least 2 years.
SSRI side effects?
GI-dyspepsia, N and V, diarrhoea insomnia fatigue sexual dysfunction flushing dizziness weight loss? and loss of appetite? increased risk of bleeding-be careful with co-prescribing aspirin/NSAIDs
2nd line treatment of depression and anxiety?
SNRIs e.g. Venlafaxine and duloxetine
Desired dopamine pathway for antipsychotic action?
Mesolimbic pathway
Drugs used for rapid tranqulisation?
Haloperidol (typical antipsychotic) and lorazepam
Antipsychotic onset of action?
1 to 4 weeks
Why must lithium not be stopped suddenly?
Can precipitate mania necessitating hospital admission
what is trazodone and what is its MOA?
classed in ‘other antidepressants’
thought to potentiate noradrenergic neurotransmission without affecting reuptake of NA, and may have a central antiserotonin effect responsible for its ability to reduce anxiety.
strong sedating properties
few anticholinergic side effects e.g. urinary retention if prostatic hypertrophy
TCA used in OCD?
clomipramine (mainly 5HT)
least cardiotoxic TCA?
lofepramine (mainly NA reuptake inhibitor)
what are agomelatine and tryptophan?
other antidepressants
agomelatine- melatonin receptor agonist, selective serotonin antagonist.
tryptophan- adjunctive therapy for depression
MOA of MAOIs?
block intracellular breakdown of dopamine, 5HT, NA and tyramine
why is there a risk of a hypertensive crisis with MAOIs?
tyramine hypertensive crisis: if increase tyramine, then more NA is pushed out from cells.
also known as ‘cheese reaction’ as cheese-high tyramine content.
moclobemide-selective, so less tyramine reaction.
important early symptom of the hypertensive crisis which may result in a cerebral haemorrhage is a severe, usually throbbing, headache.
drugs other than antidepressants which may cause the serotonin syndrome?
tramadol