Psychopharmacology Flashcards
What basis is selection of antidepressants based upon?
Generally no difference in efficacy so based on: -Any past history of response -Side effect profile -Coexisting medical conditions
How long does it take for symptoms to improve when an antidepressant is diagnosed? What should be done if symptoms do not improve?
Delay of 3-6 weeks after a therapeutic dose is reached before symptoms improve. If no improvement is seen after prescription of an adequate dose for at least two months then the treatment should be switched to another agent or augmented with one
What are the classes of antidepressant?
Tricyclics (TCAs) Monoamine Oxidase Inhibitors (MAOIs) Selective Serotonin Reuptake Inhibitors (SSRIs) Serotonin/Noradrenaline Reuptake Inhibitors (SNRIs) Novel antidepressants
What is the mechanism behind tertiary TCAs?
Act on serotonin receptors
What are the side effects of tertiary TCAs?
Antihistaminic Anticholinergic Antiadrenergic QT lengthening
What are some examples of tertiary TCAs?
Amitriptyline Clomipramine Imipramine Doxepin
When should tertiary TCAs be avoided and why?
In high risk suicide patients as they can be taken in overdose
What is the mechanism behind secondary TCAs?
Block noradrenaline
What are the side effects of secondary TCAs?
Similar to tertiary TCAs but less severe
What are some examples of secondary TCAs?
Desipramine Nortriptyline
What is the mechanism behind monoamine oxidase inhibtors?
Binds irreversibly to monoamine oxidase, preventing inactivation of amines (norepinephrine, dopamine, serotonin) and so increases synaptic levels
What are the side effects of monoamine oxidase inhibitors?
Antiadrenergic side effects Antihistaminic side effects Dry mouth Sleep disturbance Hypertensive crisis if eating tyramine rich foods (cheese, red wine, processed meats, beans) Serotonin syndrome (more info below) can develop if also taking meds that increase serotonin/have sympathomimetic actions
What are some examples of monoamine oxidase inhibitors?
Phenelzine Tranylcypromine Selegiline
In what situation is a monoamine oxidase inhibitor most effective?
Treatment resistant depression
What mechanism is behind selective serotonin reuptake inhibitors?
Blocks presynaptic serotonin uptake
What are the side effects of selective serotonin reuptake inhibitors?
GI upset (most often nausea) Sexual dysfunction (most common reason for discontinuation by patient) Anxiety Restlessness Nervousness Insomnia Fatigue/sedation Dizziness
What are some examples of selective serotonin reuptake inhibitors?
Paroxetine Sertraline Fluoxetine Citalopram Escitalopram Fluvoxamine
What are the symptoms of SSRI discontinuation syndrome?
Agitation Nausea Disequilibrium Dysphoria Usually lasts 7-10 days
What is the mechanism behind serotonin/norepinephrine reuptake inhibitors (SNRIs)?
Inhibits both serotonin and noradrenergic reuptake like TCAs
What are some examples of SNRIs?
Venlafaxine Duloxetine
What are the possible uses of SNRIs?
Depression Anxiety Neuropathic pain
What is the mechanism behind mirtazapine?
Different mechanism of action may provide good augmentation for SSRIs Can be used as hypnotic at lower doses
What are the side effects of mirtazapine?
Increases serum cholesterol Sedative at low doses Weight gain
What are the side effects of buproprion?
Seizure risk at high doses Anxiety Agitation Insomnia Psychotic side effects at high doses
What are the contraindications of buproprion?
Traumatic brain injury Bulimia Anorexia
What are the symptoms of serotonin syndrome?
Abdominal pain Diarrhoea Sweats Tachycardia Hypertension Myoclonus Irritability Delirium
What are the potential complications of serotonin syndrome?
Hyperpyrexia Cardiovascular shock Death
How is serotonin syndrome prevented?
Wait for two weeks when switching from an SSRI to an MAOI, with the exception of fluoxetine where you need to wait for five weeks due to the long half-life
What is activation syndrome and when does it occur?
Activation syndrome occurs when serotonin increases in the brain and can cause nausea and increased levels of anxiety. Usually goes away after a few days of prescription but can be prolonged.
How is antidepressant prophylaxis given?
Following first episode- 6 months prophylaxis Following second episode- 2 years prophylaxis Following third episode- lifelong prophylaxis
How is treatment resistant depression managed?
Generally- change SSRI to SNRI then add to SNRI Combination of antidepressants Adjunctive treatment with lithium Adjunctive treatment with atypical antipsychotic (Quetipaine, olanzapine, aripiprazole) Electroconvulsive therapy
What are the possible indications for mood stabilisers?
Bipolar disorder Cyclothymia Schizoaffective disorder
What are the classes of mood stabilisers?
Lithium Anticonvulsants Antipsychotics
In what situations is lithium helpful?
Only medication to reduce suicide rate Effective in long term prophylaxis of depressive and manic episodes
What factors predict a good response to lithium?
Prior long-term response or family member with good response Classic pure mania Mania is followed by depression
What monitoring should be done with a lithium prescription?
Before lithium is started a baseline Us&Es and TSH should be done, as well as a pregnancy test in women of child bearing age. Lithium can cause Ebstein’s anomaly is prescribed during the first trimester and is nephrotoxic and can cause hypothyroidism. The goal blood level is 0.6-1.2, which can be achieved after five days and should be checked 12 hours after the last dose at this point. Levels should be checked at 3 months and creatinine and TSH checked at 6 months.
What are the side effects of lithium?
GI distress- reduced appetite, N&V, diarrhea Thyroid abnormalities Nonsignificant leukocytosis Polyuria/polydipsia secondary to ADH antagonism (can cause interstitial renal fibrosis, hair loss and acne in small number of patients) Reduces seizure threshold Cognitive slowing Intention tremor
What blood levels define each type of lithium toxicity?
Mild = 1.5-2.0 Moderate = 2.0-2.5 Severe = >2.5
What are the symptoms of mild lithium toxicity?
Vomiting Diarrhea Ataxia Dizziness Slurred speech Nystagmus
What are the symptoms of moderate lithium toxicity?
Nausea Vomiting Anorexia Blurred vision Clonic limb movements Convulsions Delirium Syncope
What are the symptoms of severe lithium toxicity?
Generalised convulsions Oliguria Renal failure
What factors predict a good response to valproic acid?
Rapid cycling patients (female>male) Comorbid substance issues Mixed patients Patients with comorbid anxiety disorders Good in mania prophylaxis but not so good in depressive prophylaxis
What monitoring should be done with a valproic acid prescription?
Before the medication is started baseline LFTs, FBC and a pregnancy test are done. The drug is generally not started in anyone of child bearing age, but a folic acid supplement should be given if it is started in women. A steady state is achieved after 4-5 days and levels should be checked 12 hours after this dose. LFTs should also be repeated at this point. The target level is 50-125
What are the side effects of valproic acid?
Thrombocytopenia and platelet dysfunction N&V Weight gain Sedation Tremor Hair loss Risk of neural tube defect in pregnancy
What are the uses of carbamazepine?
First line medication for patients with acute mania and mania prophylaxis. It is indicated in rapid cyclers and mixed patients
What monitoring is required with a carbamazepine prescription?
Baseline LFTs, FBC and an ECG Check levels after reaching therapeutic doses- five days later and then again at a month
What are the side effects of carbamazepine?
Rash (most common side effect) N&V Diarrhoea Sedation, dizziness, ataxia and confusion AV conduction delays Aplastic anemia and agranulocytosis Water retention Drug-drug interactions (many contraindications)
What are the side effects of lamotrigine?
N&V Sedation, dizziness, ataxia and confusion Toxic epidermal necrolysis/steven johnsons syndrome (if ANY rash develops- stop drug) Blood dyscrasias (rare) Valproate doubles concentration
What antipsychotics can be used in manic patients?
Aripiprazole Risperdone Quetiapine Quetiapine XR Olanzapine
What antipsychotics can be used in mixed patients?
Aripiprazole Risperdone Olanzapine
What antipsychotics can be used in maintenance situations?
Aripiprazole Quetiapine Quetiapine XR Olanzapine
What antipsychotics can be used in depressed patients?
Quetiapine XR
What are the possible indications for antipsychotics?
Schizophrenia Schizoaffective disorder Bipolar disorder Psychotic depression Augmenting agent in treatment resistant anxiety
What are the characteristics of typical antipsychotics?
D2 dopamine receptor antagonists Extrapyramidal side effects common Can be split into low potency and high affinity Low potency: Interact with nondopaminergic receptors, causing cardiotoxic and anticholinergic side effects High potency: Higher risk of extrapyramidal side effects due to high affinity for D2 receptors
What are some examples of low and high potency typical antipsychotics?
Low potency- chlorpromazine, thioridazine High potency- fluphenazine, haloperidol, pimozide
What are the characteristics of atypical antipsychotics?
Serotonin-dopamine 2 antagonists Don’t get extrapyramidal side effects but do cause weight gain
What are some examples of atypical antipsychotics?
Risperidone Olanzapine Quetiapine Aripiprazole Clozapine
What treatments can be given in antipsychotic resistant patients?
Clozapine If clozapine fails: -Add another antipsychotic -Add lithium/anticonvulsant -ECT
What additional measures are required with a clozapine prescription?
Due to the risk of agranulocytosis it is required that patients on clozapine have weekly blood tests for the first six months of prescription followed by fortnightly blood tests for the next six months
How long should prophylaxis be given after a schizophrenic episode?
Lifelong prophylaxis required
What are the potential serious adverse events that are associated with antipsychotics?
Tardive dyskinesia Neuroleptic malignant syndrome Extrapyramidal side effects- acute dystonia, parkinsonism syndrome, akathisia
What drugs can be given to reduce extrapyramidal side effects?
Anticholinergics (benztropine etc) Dopamine facilitators (Amantadine) Beta-blockers (propranolol)
What is akathisia?
Characterised by a feeling of inner restlessness and inability to stay still and is associated with an increased risk of suicide
What are the indications for anxiolytics?
Panic disorder Generalised anxiety disorder Substance-related disorders Insomnias and parasomnias Often used in conjunction with SSRIs/SNRIs in anxiety disorders
What are the key anxiolytics?
Buspirone and benzodiazapines
What are the pros and cons of buspirone?
Pros- no sedation and it works independent of exogenous serotonin Cons- it takes around two weeks to work and it will not work if patients are used to benzodiazapines
What can benzodiazapines be used to treat?
Insomnias Parasomnias Anxiety disorders CNS withdrawal states
What are the side effects of benzodiazapines?
Somnolence Cognitive deficits Amnesia Disinhibition Tolerance Dependence
What are some examples of benzodiazapines?
Diazepam Temazepam Alprazolam (Xanax) Lorazepam
What are the antihistaminic side effects?
Sedation Weight gain
What are the anticholinergic side effects?
Dry mouth Dry eyes Constipation Memory deficits Delirium
What are the antiadrenergic side effects?
Orthostatic hypertension Sexual dysfunction Sedation
