Psychiatry Flashcards
Tricyclic Antidepressants
Name (3) and MoA
Amitriptyline, Lofepramie, Imipramine
Inhibit neuronal reuptake of NA and 5HT-3 at synaptic cleft to increase neuroavailability
TCAs - Indications
Moderate-severe depression treatment, neuropathic pain (unlicensed)
TCAs - Contraindicaitons
Elderly, CVD (prolongs QT), epilepsy, constipation, BPH, raised intraocular pressure
TCAs - Side effects
Mainly caused by reuptake inhibition of muscarinic, histamine, alpha-adrenergic and dopamine receptors.
Toxicity at high dose –> cardiac arrest.
High risk of suicidal thoughts
Dry mouth, constipation, retention, blurred vision, sedation, hypotension, QT^, sexual dysfunction, extrapyramidal sx (tremor, dyskinesia)
TCA - interactions
MAOIs - synergistic
SSRIs - name (4) and mechanism
Citalopram, sertraline, fluoxetine, esciptalopram
MoA - preferential inhibition of 5-HT reuptake, improves mood and relieves panic/obsession
SSRI Indications
First line moderate-severe depression medicaiton, panic disorder, OCD
SSRI contraindicaitons
Epilepsy, PUD, young, hepatic imp
Paroxetine - C/I in pregnancy
SSRI side effects
GI - appetite/weight, nausea, vomiting, diarrhoea (squirtraline) hyponatraemia, suicidal thoughts (in young), serotonin syndrome, QT^
Neuro - insomnia, irritability, sometimes mania, anxiety
Spinal - ED
Discontinuation - other than fluoxetine, rapid withdrawal can cause anxiety, headaches, sweats
SSRI interactions
MAOI/SNRIs - risk of serotonin syndrome Fluoxetine - long T1/2 Paroxetine - short onset/offset Aspirin/NSAIDs - caution with PUD Other QT^ drugs (esp Citalopram)
Benzodiazepines Name (5) and mechanism
Diazepam (2-keto, long half-life) Lorazepam (3-hydroxy, short half-life) Chlordiazepoxide Midazolam Nitrazepam
GABA(A) agonist increase Cl- inflow to decrease stimulation reducing anxiety, leads to sleepiness sedation, anti-convulsive
Benzos - Indications (5)
Seizures Alcohol WD Sedation Short-term (severe) anxiety relief (e.g. pre-operative) Insomnia
Benzos - Contraindications/Cautions
Stronger in elderly (risk of falls) Respiratory Depression NMD Liver failure (due to metabolism) In drink - more potent
Benzos - Side Effects
Sedation/coma - risk of falls
Some central respiratory depression in OD
Anterograde amnesia/confusion
Loss of AW reflexes
Dependence/tolerance/withdrawal (minimise duration)
Benzos - Interactions (2)
Additive to other sedatives
Dep on CYP450 for clearance
Acetylcholinesterase inhibitors
Name (3) and Mechanism
Donepazil, galantamine, rivastigmine
Irreversibly binds cholinesterase to inhibit ACh hydrolysis and increase availability at synapse, thereby stimulating neurones
AChEi
Indications
Mild-severe dementia assoc with Alzheimer’s
AChEi
Side Effects
Muscle cramping, joint pain, ^micturition/incontinence, seizures, faints, arrhythmias, GI ulceration
AChEi
Interactions
Atropine - counters
CYP450 as elimination hepatic
Z-drugs
Name (2) and Mechanism
Zopidem/Zopiclone
Act on GABA(A) receptor subunit alpha-1 to increase Cl- influx into neurone and reduce stimulation (hyperpolarisation)
Z-drugs
Indication
Insomnia
Z-drugs
Cautions/Contraindications
Contra-indicated in myaesthenia gravis, hepatic impairment
Caution dependence, withdrawal
Z-drugs
Side Effects
Dry mouth
CNS depression - drowsiness, dysguesia (bitter)
Name a drug used for Generalised Anxiety Disorder AND/OR Neuropathic pain (/Epilepsy)
Pregabalin
Pregabalin
Cautions/Contraindications
Renal clearance - caution in renal impairment
Increases appetite - caution in diabetes
Pregabalin
Side Effects
Increased appetite/weight gain Nasopharyngitis Euphoria/confusion Dizziness/drowsiness Diplopia GI upset
Mechanism of Action of Memantine
Memantine is an NMDA antagonist - this prevents the excitotoxic glutamate from opening the NMDA channel to inhibit Na influx to cells, reducing toxic excitation
Monoamine Oxidase Inhibitors (MAOIs)
Name (2)
Mechanism
Hydrazine / Selegiline
Inhibit pre-synaptic monoamine oxidase enzyme to increase neurotransmitter availability
MAOIs
Cautions
Interact with CYP process so increase concentration of other drugs.
Very restrictive diet - fruits, alcohol, dairy, meats
Effects all NTMs
SNRIs
Name and Mechanism
Venlafaxine
Duloxetine
Selectively inhibits noradenrenaline reuptake
SSRIs
Counselling
Start at a half dose and titrate up after two weeks.
Likely to take up to 4 weeks to have an effect, then will persist for at least 6 months once desired effect is achieved.
Side effects, if any, likely to occur in first week, but will improve with time. If not resolved in 4 weeks then we’ll reconsider.
Esp young - risk of suicidal thoughts. If that occurs, safety net is ring GP or talk to family.
May be nauseous, diarrhoea, vomiting initally, but should improve with time
May cause irritability, restlessness, insomnia
Can cause erectile dysfunction.
Fluoxetine esp likely to increase appetite and cause weight gain.
SNRIs Name (2) and Mechanism
Venlafaxine/Duloxetine
Selectively inhibit serotonin and noradrenaline reuptake
SNRIs
Indications
Depression (2 x failed SSRIs for 6/12)
Anxiety
Neuropathy & Fibromyalgia
(Migraine - amitryptiline)
SNRIs
Side Effects
NA - increased HR & BP
Risk of narrow-angle glaucoma
Otherwise as SSRIs
SNRIs
Cautions
Coupled with SSRIs can lead to increased risk of serotonin syndrome
Venlafaxine cam cause hypertension (due to NA)
NaSSAs
Name and Mechanism
Mirtazapine
Noradrenergic receptor antagonist and selective serotonin antagonist
Mirtazapine
Side Effects
Histamine inhibitor - sleepiness, increased appetite
Anti-cholinergic - dry mouth, postural hypotension
Mirtazapine
Side Effects
Histamine inhibitor - sleepiness, increased appetite
Anti-cholinergic - dry mouth, postural hypotension
First Line Mood Stabiliser and Mechanism
Lithium
?Inhibit of neuronal membrane lipid recycling
Alternative uses of lithium
Mania
Recurrent/refractory depression
Bipolar Affective Disorder
Target therapeutic range for lithium
Acute: 0.8-1.2
Chronic: 0.4-0.8
Side effects of Lithium
Thirst Polyuria (lithium-induced diabetes insipidus) Tremor QT prolongation Toxicity Hyponatraemia (nephrotoxic) Hypothyroidism
Lithium Toxicity presentation
Mild - N&V, dizzy
Moderate - Confusion, fasciculations, choreoathetoid movements
Severe - coma, convulsions, sinoatrial block, circulatory collapse
Alternative Mood stabilisers (to lithium) (3)
(semi)Sodium Valproate
Lamotrigine
Carbamazepine
Contraindication of Sodium Valproate
Women of child bearing age (unless on pregnancy prevention programme) due to teratogenicity - NTDs
Acute porphyria
Liver failure - hepatic necrosis
Side effects of Sodium Valproate
GI upset Agitation, confusion Movement disorders Nystagmus Hyponatraemia
Lamotrigine uses
Bipolar
Antiepileptic
Lamotrigine side effects
Aggression Agitation GI upset Fatigue Sleep disorders
Action of Serotonin
Head - satisfaction, sociality (less impulsive), reduced sex drive
Red - reduced platelets
Fed - GI motility, nausea
Two broad categories of antipsychotics and related info
Typical/1st Generation - more neurological side effects, as ‘neuroleptics’
Atypical/2nd Generation - more metabolic side effects, act on DA and SER
DOPAMINE role mnemonia
Drive (motivation) PsychOsis Parkinsonism Attention Motor control Inhibition of prolactin Narcotics Extrapyramidal SE
To which pathway do each of these belong Drive PsychOsis Prolactin Narcotic addiction EPSE
Drive - mesocortical PsychOsis - mesolimbic Prolactin - tuberoinfundibular Narcotics - Ventral Tegmental Area (nucleus accumbens) EPSE - nigrostriatal
Describe the gait (parkinsonian)
Slow to start, stooped, shuffling, fenestrating (speeds up)
Describe EPSE
Acute Dystonia (muscle) - hours
Akathisia (rustle) - days
Akinesia (hustle) - month
Tardive Dyskinesia - can become irreversible (esp 1st Gen)
Treatment for acute dystonia
Anticholinergic e.g. Procyclidine IM
Result of excess prolactin
Hyperprolactinaemia results in gynaecomastia (esp risperidone), reduced libido, galactorrhoea
Patient is confused, agitated, hyperthermic, muscular rigidity and seizures - recently started on typical antipsychotic - Dx and Rx
Neuroleptic malignant syndrome - Dantrolene
Cautions for Depot
Ensure patient has trialled drug PO to ensure no hypersensitivity
Use of Haloperidol
Strongly binds to D2 giving strong effect but also results in EPSE.
Can be given as depot
Defining side effect of chlorpromazine
Corneal Deposits
Most effective antipsychotic and cautions.
Clozapine
3rd Gen - highly effective
Leads to agranulocytosis, and reduce seizure threshold
Strong antipsychotic with pro-appetite effect and cautions.
Olanzapine
Dyslipidaemia/metabolic syndrome and QTc prolongation.
This antipsychotic is preferred in elderly to reduce sedation and low EPSE side effects.
Risperidone
Cautions with quetiapine
Required titrating dose and can cause postural hypotension
Aripiprazole mechanism
Regulatory effect on DA and SER receptors - used for augmentation of antidepressant (refractory)
Other than serotonin syndrome, which dangerous condition can be caused by SSRIs
Hyponatraemia - due to SIADH
SIADH Presentation
Anorexia/Nausea Aches Myoclonus/ataxia Cheyne-Stokes breathing Seizures
Common abnormality associated with taking lithium in pregnancy
Ebstein’s Anomaly - low implanted tricuspid valve
Name two nocturnal benzodiazepines
Temazepam
Nitrazepam
TCA overdose signs
Arrhythmia, seizures, metabolic acidosis, coma
TCA overdose ECG findings
Sinus tachycardia
Wide QRG
QT prolongation
Opioid misuse signs and complications
Rhinorrhoea, tracks, pinpoint pupils, drowsy, watering eyes, yawning
Infection (Hep, IE, septic arthritis, sepsis, nec fasc) VTE Resp depression Craving - psych Social - cost/crime
