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Psychiatric Drugs Guide
- 1. Psych Druuuuugs • Anti depressants • Mood Stabilisers • Anti psychotics • Anxiolytics and Hypnotics
- 2. Anti depressants • How do they work? Increase levels of good mood chemicals (serotonin and noradrenaline) • Where do they work? In the presynaptic cleft Specific Serotonin Reuptake Inhibitor (SSRI) Noradrenaline reuptake inhibitor (NRI) Tricyclic antidepressant (TCA) Mono Amine Oxidase Inhibitor (MAOI) Reversible Inhibitor of Mono amine oxidase A (RIMA)
- 3. In more detail….. • So serotonin and noradrenaline are MONOAMINE NEUROTRANSMITTERS (made at the presynaptic cleft)
- 5. Selective Serotonin Reuptake Inhibitors (SSRI’S) FLUOXETINE SERTRALINE PAROXETINE CITALOPRAM Side effects: • Nausea • Vomiting • Anxiety • Agitation • Insomnia • Loss of appetite • Sexual dysfunction Anorgasmia & delayed ejaculation Contra-indication: MANIA
- 6. Noradrenaline Reuptake Inhibitor (NRI) REBOXETINE
- 7. Tri Cyclic Antidepressant (TCA) AMITRYPTYLINE CLOMIPRAMINE IMIPRAMINE LOFEPRAMINE
- 8. Tri Cyclic Antidepressant side effects • Muscarinic acetylcholine receptor: Blurred vision Dry mouth Constipation and urinary retention QT interval prolongation ST segment elevation Heart block Arrthymias
- 9. Tri Cyclic Antidepressant side effects • Histaminergic receptor Weight gain Sedation
- 10. Tri Cyclic Antidepressant side effects • Alpha adrenergic receptor Postural Hypotension
- 11. Mono Amine Oxidase Inhibitors (MAOI) MAOI’s: PHENELZINE TRANYLCYPROMINE ISOCARBOXAZID RIMA’s: MOCLOBEMIDE Side effects: Similar to TCA
- 12. Mono Amine Oxidase Inhibitors (MAOI) Side effects • Accumulation of monoamine neurotransmitter • ‘Life Threatening Hypertensive Crisis’ • How can we prevent this happening? • Reduce other amines in the body (amines found in certain foods and drugs) • TYRAMINE rich foods: strong cheese, yeast and protein extract (marmite, Bovil, oxo) CHEESE CRISIS • TYRAMINE rich drugs: adrenaline, noradrenaline, amphetamines, cocaine, dopamine, decongestants • FOOD RESTRICTIONS WHEN ON MAOI’s
- 13. SEROTONIN SYNDROME • When SSRI’s are administered simultaneously with MAOI’s or (MAOI’s with opiates) SYMPTOMS: (occurs in a few minutes) • AGITATED • FEVER • SWEATING • INCREASE HR • MYOCLONUS • OVER RESPONSIVE REFLEXES
- 14. Contra indications for starting MAOI • Phaeochromocytoma • Cerebrovascular Disease • Hepatic Imparement • Mania
- 18. Mood stabiliser - Lithium • How does it work? • Before you start taking it…. • Check patient medications before prescribing.. • How long does it take to start working? • Common side effects? • Lithium Toxicity • Monitoring • Contraindications
- 19. Mood stabiliser - Lithium •NOT ADDICTIVE
- 20. Antipsychotics Conventional (typical) antipsychotics • Cause EPSE because blocks dopamine D2 Receptors in other parts of the brain Atypical antipsychotics • First line treatment for schizophrenia Because has less effect on dopamine D2 Receptors so fewer EPSE’s
- 21. Indications (psych) • Schizophrenia • Schizoaffective disorder • Delusional Disorder • Depression or mania with psychotic features • Delirium • Behavioural disturbance in dementia • Severe agitation
- 22. Non psych indications • Motor tics (tourettes) • Nausea and vomiting • Intractable hiccups and pruritus
- 23. Conventional/typical antipsychotics • Chlorpromazine • Thioridazine • Trifluoperazine • Haloperidol Phenothiazines
- 24. Clinical side effects of using conventional/typical antipsychotics Because of non-specific blocking of receptors – Has similar side effects to TCA’s Chemoreceptor trigger zone
- 25. Atypical antipsychotics • Clozapine • Olanzapine • Resperidone NB all cause weight gain and increase risk of diabetes. CLOZAPINE – agranulocytosis
- 26. Drug Recap Chlorpromazine Thioridazine Trifluoperazine Haloperidol Resperidone Olanzapine Clozapine
- 27. Anxiolytic and Hypnotic drugs • BENZODIAZEPINES
- 29. Indication of Benzo’s • Anxiety • Alcohol withdrawal • Akathisia • Acute mania or psychosis • Epilepsy prophylaxis • (any reason someone might need to CHILL out)
- 30. Side effects • Drowsy, ataxia (using machinery/driving) • Can depress respiration centre so caution in chronic resp patients • Risk of developing dependence • OVERDOSE • USE WITH OTHER DRUGS (ESP ALCOHOL)
- 31. Benzo’s • Temazepam SA oral • Oxazepam SA oral • Lorazepam SA oral, IV, IM • Diazepam LA oral, PR, IV, IM • Chlordiazepoxide LA oral
Notas del editor
- There are 2 chemicals involved with mood: serotonin and noradrenaline. When these chemicals are in the synaptic cleft they lighten the mood and when they leave the synaptic cleft (are reabsorbed) they no longer have an effect on mood. Therefore the aim of antidepressants is to keep these chemicals in the synaptic cleft for as long as possible.
- These drugs selectively inhibit the serotonin reuptake pumps on the presynaptic cleft FLUOXETINE SERTRALINE PAROXETINE CITALOPRAM
- This drug selectively blocks the presynaptic noradrenaline reuptake pump Eg REBOXETINE
- TCA’s block the reuptake of noradrenaline and serotonin reuptake pumps on the presynaptic cleft. Also blocks the muscarinic, histaminergic and alpha adrenergic receptors (which is why there are quite a few side effects with TCA’s)
- Muscarinic acetylcholine causes an effect on secretory exocrine glands and on smooth cardiac muscle: secretion from salivary glands and stomach Slows heart rate Reduces contractile force of atrium Reduces conduction velocity of av node Eye accommodation
- Commonly causes vaso constriction of arteries and veins so when stimulated causes blood pressure to be normal. If alpha adrenergic receptor is blocked then causes postural hypotension (dizziness and syncope)
- MOA = an enzyme that breaks down monoamine neurotransmitters (serotonin and noradrenaline) Non selective and irriversible inhibition of monoamine oxidise A and B (there are 2 isomers of monoamine neurotransmitters) RIMA (reversible inhibitor of monoamine oxidase A) Works by selectively and reversibly inhibiting monoamine oxidase A
- Inhibition of monoamine oxidase A means there is an accumulation of monoamine neurotransmitter As there is lots of monoamine neurotransmitter it means that the metabolism of other amines is affected and they are not broken down, meaning that as MAOI binds irriversibly amine levels can accumulate to DANGEROUSLY high levels. The high levels of amine causes a MASSIVE release in norodrenaline and this causes a LIFE THREATENING HYPERTENSIVE CRISIS CHEESE CRISIS = strong cheese can cause high levels of tyramine – early warning sign = a throbbing headache RIMA’s REVERSIBLY INHIBIT MAOA so the drug is displaced when amine levels increase so no food restrictions required.
- Shouldn’t start TCA or SSRI for 2 weeks after stopping MAOI (give it 3 weeks for clomipramine and imipramine) Shouldn’t start MAOI for 1-2 weeks after stopping another antidepressant 3 weeks for clomipramine and imipramine 5 weeks for fluoxetine
- Small vascular tumour in the adrenal gland) causing uncontrolled release of adrenaline and noadrenaline causing increase in BP and HR palpatations and headache Cerebrovascular disease Hepatic imparement Mania!!
- Both conventional and atypical antipsychotics have extra- pyramidal side effects because of the effect on other dopamine D2 receptors in other parts of the brain.
- Have Dopamine receptors located in these other areas…means their normal function is stopped Mesolimbic pathway – these receptors are involved in delusions, hallucinations, thought disorder, euphoria and drug dependance So BLOCKING OF THESE RECEPTORS = TREATMENT FOR PSYCH SYMPTOMS 2) Mesocortical pathway – mediates cognitive and negative symptoms of schizophrenia so BLOCKING OF THESE RECEPTORS MEANS WORSENING OF NEGATIVE AND COGNITIVE SYMPTOMS OF SCHIZO 3) Nigrostriatal pathway (basal ganglia)– controls motor movement so if blocked get EPSE – parkinsonium symptoms, acute dystonia, akathisia, tardive dyskinesia, neuroleptic malignant syndrome (rare but life threatening condition – a reaction to neuroleptic medication – get fever, muscle rigidity, fever, altered mental status and autonomic dysfunction) 4) Tuberoinfundibular pathway – controls prolactin secretion. (Dopamine inhibits prolactin secretion) So if blocked get: HYPERPROLACTINAEMIA, GALACTORRHOEA (BREAST MILK PRODUCTION), AMENNORRHOEA, SEXUAL DYSFUNCTION. 5) CHEMORECEPTOR TRIGGER ZONE: so when this is functioning normally is allows you to feel sick and to be sick. Blocking the pathway means that you cant be sick so is an anti-emetic
- Clozapine – very effective antipsychotic but there is a risk of life threatening bone marrow supression due to a side effect being agranulocytosis and it is only used for ‘treatment-resistant schizophrenia’ Also can cause seizures at a high dose and hypersalivation Olanzapine Resperidone
- Benzodiazephines bind to specific benzo receptors in the GABA A receptor which causes increased affinity of the complex of GABA. So get an increase affinity for chloride ions into the neurone which causes hyperpolarisation of the post synaptic membrane (therefore preventing depalarisation and an action potential)
- Alcohol, opiates, barbituates TCA, antihistamines may enhance the effect of benzo’s and cause resp depression
- Lorasewpam only benzo with predicatable absorption when given IM.
- ANTIDEPRESSANTS – SSRI, NRI, TCA, MAOI’s, RIMA (REVERSIBLE INHIBITOR OF MA), MOOD STABILISER ANTI PSYCHOTIC – TYPICAL (CONVENTIONAL) AND ATYPICAL ANXIOLYTIC / SEDATIVE – LA AND SA BENZOS