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Psych drugs

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imo132's version from 2016-11-23 04:25

Drugs

Question Answer
East Asians & APsMore susceptible to EP & ACh SE, lower risk of tardive dyskinesia (DRD2/3 polymorphisms)
Olanzapine RxMania & depression
Quetiapine RxMania & depression
Typical AP SEAcute dystonia/akathisia, Parkinsonism (ACh, movement), tardive dyskinesia
Lithium SEHypothyroidism (Rx thyroxine), polyuria & polydipsia, fine tremor, muscular weakness, EPSE, memory difficulty, metallic taste, N&V
Lithium mechanismInhibits phosphoinositide pathway to increase BDNF
Lithium therapeutic range0.5-1.2, check after 5 days of initiating/changing (steady state)
Lithium monitoringEvery 3-6 mo (8 hours after last dose), EUC every 3-6 mo, TFTs every 6-12 mo, calcium annually
Lithium toxicity>1.5-2 mmol/l, with dehydration from poor fluid intake, diarrhea/vomiting, diuretics
Lithium toxicity SxAtaxia, vomiting, coarse tremor, hemiplegia, disorientation, dysarthria, myoclonus, impaired consciousness, hypertonia, seizures, long QT, AKI, death
Anticonvulsant SEBetter tolerated than lithium but breakthrough Sx, PCOS, hair loss
ParoxetineHighest rate of discontinuation symptoms (with venlafaxine), with weight gain, sexual dysfunction
Short half-life ADParoxetine, fluvoxamine, venlafaxine, high rates of discontinuation symptoms
Long half-life ADFluoxetine, low risk of discontinuation symptoms
ClozapineAtypical, fewer EPSE, lowest mortality & suicide rate
HaloperidolTypical AP, most commonly discontinued AP, weight neutral
Haloperidol SEExtrapyramidal SE (Rx benztropine, anticholinergic)
Typical APD2, mesolimbic, high potency & D2 affinity, phenothiazines (chlorpromazine), butyrophenones (haloperidol), thioxanthenes (flupenthixol)
Atypical AP5HT2A & D2 antag, partial 5HT1A & D2 agon, less EPSE & hyperprolactin
Aripiprazole RxMania
SSRIsWeak ADs, good in anxiety, all equally effective, harmless in overdose, slow response, can use in depression/anxiety, can use in drug/alcohol dependence
SSRI SELow libido & orgasm, fuzzy head, jitteriness at beginning, withdrawal, nausea, diarrhoea, dizziness, headache, insomnia, suicidal ideation
SNRIsUsed in melancholic depression, withdrawal syndrome common, venlafaxine cardiotoxic, duloxetine
TCAsMost effective in depression but ACh & histamine SE, give at night as sedating, slow response, poor tolerability, used in depression/anxiety, not safe in overdose, can use in drug/alcohol use
TCA SEDry mouth, cavities, drowsiness, weight gain, hypoTN, cardiotoxicity, long QT (ECG), sedation, sexual dysfunction
Cheese reactionMAO-I inhibits gut MAO-A transporter and increases tyramine absorption, displaces NA & A, causing ICH
Tyramine-rich foodsCheese, salami, beer, chocolate, coffee, liver, herring, vegemite, sauerkraut
ECTFor melanchotic/psychotic depression, inability to eat, suicidal or tormented, bipolar, mania, need 6-18 treatments, 2-3x per week
ECT mechanismR frontal & temporal lobe (avoid L hippocampus for memory)
ECT SESpotty retrograde memory loss, post-ictal headache & confusion, BP instability, bradycardia
Extrapyramidal SEFrom blocking D2 in nigrostriatal pathway, from haloperidol, typicals, metoclopramide, dose-related
DystoniasIn 10%, young males, neuroleptic-naive, high potency drugs eg haloperidol, substance abuse, onset minutes if IM/IV, Rx ECT, Botox
Pseudo-parkinsonismSimpson-Angus Rating, in 20%, elderly females, head injury, stroke, with salivation, onset days-weeks, Rx reduce dose, atypical, anticholinergic during day
AkathisiaFrom risperidone, ziprasidone, aripiprazole, unlikely with clozapine, quetiapine
AkathisiaRestlessness, Barnes Akathisia Scale, in 25%, with substance abuse, onset hours-weeks, from D2 blockade via 5HT2A stimulation
Tardive dyskinesia5%, elderly women, previous acute, substance abuse, haloperidol, onset months-years, Rx reduce, atypical, benzos, propranolol, Vit E
Neuroleptic malignant syndromeRare, <1%, sudden reduction in DA activity from withdrawal of dopaminergic agents or blockade of receptors, onset hours-days, with typicals
NMS SxHyperthermia (>38), EPSE (rigidity, brady/akinesia, dystonia, dysphagia, tremor), autonomic instab (tachycardia, HTN, labile BP, diaphoresis, tachypnoea), CNS effects (drowsiness, confusion, coma, mutism, incontinence)
NMS RxWithdraw inducing agent, consider benzos, rehydrate, cool, sedate, DVT prophylaxis, antidote
HyperprolactinaemiaBlocked DA-R in tuberoinfundibular pathway causes rise in prolactin, dose-dependent, also from TCAs & SSRIs via blockade of 5HT2A-R which increases DA, more risk for women
Hyperprolactinaemia APAmisulpride, typicals (haloperidol), sertindole, risperidone, paliperidone
No hyperprolactinemiaChlorpromazine, aripiprazole, quetiapine
Hyperprolactinaemia RxOlanzapine, Ziprasidone, Asenapine, Clozapine, Quetiapine, Aripiprazole (partial D2/5HT1A agonist, full 5HT2A agonist), check at 3 mo
Hyperprolactinaemia DxSerum 1 hr post waking/eating, women <25 ng/ml (530 mIU/L), men <20 (424 mIU/L), refer if >2500 mIU
Neuroleptic-induced deficit syndromeFrom blocked D2-R in mesocortical & mesolimbic pathways, worsens negative & cognitive Sx (apathy, anhedonia, amotivation)
Long QT>500 arrhythmia, >650 torsades or sudden death, APs interact with K (repolarisation), TCAs with Na (depolarisation), annual ECG
Long QT Rx>470 reduce dose or switch drug, >500 or abnormal T switch drug & refer to cardiologist
Weight gainFrom 5HT2C antag, H1 antag, hyperprolactinaemia, increased leptin, from clozapine & olanzapine
BleedingFrom SSRIs via blockage of 5HT uptake into platelets, increased with NSAIDs, anticoags & antiplatelets, liver cirrhosis, Rx add PPI
HyponatremiaFrom AD via increased ADH via high 5HT & NA, in elderly with thiazide/ACE-I, more with SNRI, less with TCA, none with Mirtaz
CYPFewer poor CYP2D6 metabolisers in Asian & African pop than caucasian but lower CYP2D6 activity in east Asians, affects citalopram dosing
SS vs NMDDiaphoresis, diarrhoea, vomiting in SS
NMD vs SSEPSE, high fever, dysphagia, incontinence, sialorrhoea in NMD
Discontinuation syndDizziness, unsteadiness, weakness, N/V, headache, anxiety, insomnia, URT Sx, paraesthesias, from paroxetine, fluvoxamine, venlafaxine (short half life), resolves over a week
Mania drugsLithium, olanzapine, aripiprazole, risperidone
Lamotrigine RxDepression, use in Bipolar II
BenzosSafe in overdose, cannot be used in drug/alcohol dependence
Drugs for withdrawalClonidine (alpha 2 agonist), lorazepam, diazepam, paracetamol/metoclopramide (headache, vomiting)
D1-REncourages use via DA release, becomes overexpressed after repeated exposure
D2-RInhibits use via inhibition of DA release
AP initiationPatient feels better after first 3 months, will relapse after 6 months if ceased
AD onset6 weeks for anxiety, 2 weeks for depression
EPSERisperidone > chlorpromazine, none with clozapine, olanzapine, sertindole, quetiapine, Rx with anticholinergics
Chlorpromazine SEPhotosensitivity
No EPSEClozapine, olanzapine, sertindole, quetiapine
Most effective APClozapine > amisulpride, olanzapine, risperidone
SertralineSSRI, activating (makes patients anxious) so take in morning, diarrhoea
CitalopramSSRI, long QT with high dose (none with escitalopram)
Teratogenic ADSSRI, lithium contra in breastfeeding, all mood stabilisers (use AP eg quetiapine)
Non-teratogenic ADTCAs, haloperidol
Schizophrenia deathMore cardiac than suicide (twice risk CHD), often sudden cardiac death from long QT, premature death by >15 years
Long QT value>450 men, 460 kids, 470 women or >60 ms above baseline, or any >500, corrected for pulse rate, altered by diurnal variation, stress, feeding
NMS20% mortality, incidence 3%, from high-potency (typical) APs, common in first 2 weeks of therapy
NMS RFInitiation of therapy, high doses, rapid escalation, switching class, IV/IM, agitation, catatonia, dehydration, lithium, depots
NMS tetradMuscle rigidity, mental state change, hyperthermia, autonomic instability
NMS DxCK >1000, high WCC (left shift), LDH, ALP, AST/ALT, metabolic acidosis, low Na, Mg, Ca, proteinuria, myoglobinuria, low iron
5HT syndrome SxCognitive (headache, agitation, hypomania, confusion, hallucinations, coma), autonomic (shivering, sweating, hyperthermia, HTN, tachycardia, nausea, diarrhea, flushing, mydriasis), somatic (myoclonus, hyperreflexia, tremor, hypertonia, rigidity)
5HT syndrome triadCognitive effects, autonomic effects, somatic effects
Clozapine deathFrom neutropenia, myocarditis, arrhythmias, respiratory depression
Acute dystoniasFrom IV/IM AP via DA blockade, laryngeal spasm lethal, Rx benztropine (anticholinergic)
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