6- Therapeutics commonly used in psychiatry (Pharmacological)) Flashcards
(140 cards)
The perfect medication in psychiatry
- Has a very specific activity on receptors (or chemicals) and only in areas where those receptors (or chemicals) are clearly implicated in the cause of the psychiatric condition or the reduction of psychiatric symptoms
- Therefore has less potential for side effects and we are able to predict effectiveness
in reality psychiatric medication have many side effects
Adrenergic/Noradrenergic:
– Sweating
– Tremor
– Headaches
– Nausea
– Dizziness
Muscarinic (Acetylcholine):
– Dry mouth, difficulty swallowing, thirst
– Difficulty urinating, urinary retention
– Hot and flushed skin. Dry skin
Histamine:
– Dry mouth
– Drowsiness
– Dizziness
– Nausea and vomiting
classes of psychiatric medication
- Antidepressants
- Antipsychotics
- Anxiolytics
- Hypnotics
- Mood stabilisers
Antidepressants background
- Most work on serotonin activity (and maybe other receptors) and aim to increase activity at post synaptic receptors
- Most have most of their effect in two to three weeks – may take up to 6 weeks to have maximum effect
- Only for the treatment of Severe or Moderate Depression, (they don’t work for mild depression)
- Most commonly used anti-depressants are SSRI’s
- Follow up after 2 weeks to screen for suicidal ideation
- Other types include:
– SNRIs
– Mirtazapine
– Tricyclics
– MAOIs (I have started once in 20 years!) - Also used to treat anxiety
Selective serotonin reuptake inhibitors (SSRIs) examples
sertraline and citalopram most popular first line
SSRI indication
- Moderate to severe depression
- Panic disorders
- Generalised anxiety
- OCD
- PTSD
MOA of SSRI
They work by inhibiting the reuptake of serotonin from the synaptic cleft into pre-synaptic neurones and therefore SSRIs increase the concentration of serotonin in the synaptic cleft.
side effects of SSRIs
Side effects
- Sense of restlessness, agitation on initiation (countered by judicious use of benzodiazepines)
- Nausea, GI disturbance
- Headache
- Weight changes
- Sexual dysfunction
- Less common – bleeding and suicidal ideation (age related)
contraindication to antidepressants
History of mania, epilepsy, cardiac disease (sertraline is the safest), acute angle-closure glaucoma, diabetes mellitus (monitor glycaemic control after initiation), concomitant use with drugs that cause bleeding, GI bleeding (or history of GI bleeding), hepatic/renal impairment, pregnancy and breast-feeding, young adults (possible
-> suicide risk), suicidal ideation.
Contraindications: Mania.
examples of noradrenaline and serotonin reuptake inhibitors (NSRIs)
Indication for SNRIs
Second or third-line
in the treatment of depression and anxiety disorders. SNRIs have
a more rapid onset of action and are more effective than SSRIs (for major depression).
MOA of SNRI
SNRIs work by
preventing the reuptake of noradrenaline and serotonin but do not block cholinergic receptors and therefore do not have as many anti-cholinergic side effects as TCAs.
Side effects of SNRIs
- Similar to SSRIs but greater potential for sedation, nausea and sexual dysfunction
contraindication to SNRIs
- Kidney or liver problems
- Heart problems
- Glaucoma
- Epilepsy, manic episodes or bipolar
- Pregnancy
tricyclic antidepressants examples
- Newer: lofepramine (safest) and nortriptyline
- Amitriptyline (less well tolerated)
indication of TCA
- depression
- nocturnal enuresis in children,
- neuropathic pain (unlicensed),
- migraine prophylaxis (unlicensed).
TCA background
- Out of favour but reasonably effective and useful for those who do not respond to SSRI’s
- Newer tricyclics (such as lofepramine and and nortriptyline) tolerated better than older tricyclics (amitriptyline)
MOA of TCA
TCAs work by inhibiting the reuptake of adrenaline and serotonin in the synaptic cleft. They also have affinity for cholinergic receptors and 5HT2 receptors and these contribute to side effects.
TCA side effects
Anticholinergic: dry mouth, constipation, urinary retention, blurred vision, confusion.
Cardiovascular: arrhythmias, postural hypotension, tachycardia, syncope, sweating. Hypersensitivity reactions: urticarial, photosensitivity.
Psychiatric: hypomania/mania, confusion or delirium (especially in elderly).
Metabolic: appetite and weight gain, changes in blood glucose levels. Endocrine: testicular enlargement, gynaecomastia, galactorrhoea.
Neurological: convulsions, movement disorders and dyskinesias, dysarthria, paraesthesia, taste disturbances, tinnitus.
Others: headache, sexual dysfunction and tremor.
TCA and overdose
causes QTc prolongation and arrhythmias
TCA complications
Cautions : cardiac disease, history of epilepsy, pregnancy, breast-feeding, elderly, hepatic impairment, thyroid disease, phaeochromocytoma, history of mania, psychoses (may aggravate psychotic symptoms), susceptibility to angle-closure glaucoma, history of urinary retention,
Contraindications: recent myocardial infarction, arrhythmias (particularly heart block), mania, severe liver disease, agranulocytosis.
Monoamine oxidase inhibitors (MAOIs) background
- If changing to another antidepressant need a washout period (up to 6 weeks)
- Should only be started by psychiatrists (in my opinion)
Monoamine oxidase inhibitors (MAOIs) examples
- Irreversible – more dangerous: Phenelzine; Isocarboxazid
- Reversible – less dangerous: Moclobamide; Tranylcypromine
Monoamine oxidase inhibitors indication
Third-line for depression: atypical or treatment-resistant depression. NOTE: Its use is substantially limited by toxicity, interaction with food and inferior efficacy compared to SSRIs and TCAs (see Key facts 2).
Social phobia.