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Pharmacology of Antipsychotics

Douglas L. Geenens, D.O. 2000. Douglas L. Geenens, D.O. 2000. Dopamine Hypothesis. Drugs that increase dopamine will enhance or produce positive psychotic symptomsE.G. Cocaine, amphetamine. Douglas L. Geenens, D.O. 2000. All known antipsychotics drugs capable of treating positive psychotic symptoms block the dopamine receptorsEsp..D-2 receptors.

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Pharmacology of Antipsychotics

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    1. Pharmacology of Antipsychotics Douglas L. Geenens, D.O. University Of Health Sciences College of Osteopathic Medicine

    2. Douglas L. Geenens, D.O. 2000

    3. Douglas L. Geenens, D.O. 2000 Dopamine Hypothesis Drugs that increase dopamine will enhance or produce positive psychotic symptoms E.G. Cocaine, amphetamine

    4. Douglas L. Geenens, D.O. 2000 All known antipsychotics drugs capable of treating positive psychotic symptoms block the dopamine receptors Esp..D-2 receptors Dopamine Hypothesis

    5. Douglas L. Geenens, D.O. 2000 Dopamine Pathways Mesolimbic Nigrostriatal Mesocortical Tuberoinfundibular

    6. Douglas L. Geenens, D.O. 2000 Dopamine Pathways Mesolimbic Projects from brainstem to limbic areas. Overactivity produces delusions and hallucinations.

    7. Douglas L. Geenens, D.O. 2000 Dopamine Pathways Nigrostriatal Projects from the substania nigra to the basal ganglia A part of the extrapyramidal system Thus side effects are called “extrapyramidal”

    8. Douglas L. Geenens, D.O. 2000 Dopamine Pathways Nigrostriatal Controls movements The term “neuroleptics” refers to: Antipsychotics ability to “quiet the neurological system” To their neurological side effects

    9. Douglas L. Geenens, D.O. 2000 Dopamine Pathways Nigrostriatal Types of movement disorders caused by this pathway include: Akathisia Dystonia Tremor, rigidity, bradykinesia Drug-induced Parkinsonism

    10. Douglas L. Geenens, D.O. 2000 Dopamine Pathways Nigrostriatal Chronic blockade can cause Potentially irreversible movement disorder “Tardive Dyskinesia” Role is undetermined

    11. Douglas L. Geenens, D.O. 2000 Dopamine Pathways Mesocortical May be associated with both positive and negative symptoms Blockade may help reduce negative symptoms of schizophrenia May be involved in the cognitive side effects of antipsychotics “mind dulling”

    12. Douglas L. Geenens, D.O. 2000 Dopamine Pathways Tuberoinfundibular Blockade produces galactorrhea Dopamine=PIF

    13. Douglas L. Geenens, D.O. 2000 Dopamine Pathways Summary Four dopamine pathways Appears that blocking dopamine receptors in only one of them is useful Blocking dopamine receptors in the other three may be harmful

    14. Douglas L. Geenens, D.O. 2000

    15. Douglas L. Geenens, D.O. 2000 Antipsychotics Phenothiazines (piperidines) Mesoridazine Serentil Thioridazine Mellaril Phenothiazines (Aliphatic) Chlorpromazine Thorazine

    16. Douglas L. Geenens, D.O. 2000 Antipsychotics Phenothiazines (piperazines) Perphenazine Trilafon Trifluoperazine Stelazine Fluphenazine Prolixin

    17. Douglas L. Geenens, D.O. 2000 Antipsychotics Thioxanthenes Navane Dibenzazepines Clozapine Clozaril Ioxapine Loxitane

    18. Douglas L. Geenens, D.O. 2000 Antipsychotics Butyrophenones Haloperidol Haldol Diphenylbutylpiperidines Pimozide Orap

    19. Douglas L. Geenens, D.O. 2000

    20. Douglas L. Geenens, D.O. 2000 Antipsychotics Indoles Molindone Moban Rauwolfia Reserpine Serpasil

    21. Douglas L. Geenens, D.O. 2000 Antipsychotics Benzisoxazole Risperidone Risperdal Thienobenzodiazepines Olanzapine Zyprexa

    22. Douglas L. Geenens, D.O. 2000 Antipsychotics Efficacy All antipsychotics are considered equally effective Rationale for determining which medication to use is based on side effect profile Primary mechanism of action is Postsynaptic blockade of the D-2 receptor “D-2, me too”

    23. Douglas L. Geenens, D.O. 2000 Antipsychotics Efficacy Newer agents e.g. Clozaril Have significant activity at the D-1 receptor; Risperdal and Zyprexa have significant 5-HT2 activity

    24. Douglas L. Geenens, D.O. 2000 Antipsychotics Potency Potency is an important variable in terms of pharmacodynamic properties of these medicines. Potency determines the predictable side effects of the antipsychotics.

    25. Douglas L. Geenens, D.O. 2000 Antipsychotics Potency Low potency medications cause more: sedation Anti-ACH Orthostatic hypotension High potency medications cause more: EPS

    26. Douglas L. Geenens, D.O. 2000 Dopaminergic D2 Blockade Possible Clinical Consequences Extrapyramidal movement disorders Endocrine changes Sexual dysfunction

    27. Douglas L. Geenens, D.O. 2000 Antipsychotics Relative potencies (mg equivalents)

    28. Douglas L. Geenens, D.O. 2000 Histamine H1 Blockade Possible Clinical Consequences Sedation, drowsiness Weight gain Hypotension

    29. Douglas L. Geenens, D.O. 2000 Antipsychotics Potency for H-1 blockade

    30. Douglas L. Geenens, D.O. 2000 Alpha-1 receptor blockade Possible clinical consequences Postural hypotension Reflex tachycardia Dizziness

    31. Douglas L. Geenens, D.O. 2000 Antipsychotics Potency for alpha-1 blockade

    32. Douglas L. Geenens, D.O. 2000 Muscarinic receptor blockade Possible clinical consequences Blurred vision Dry mouth Sinus tachycardia Constipation Urinary retention Memory dysfunction

    33. Douglas L. Geenens, D.O. 2000 Antipsychotics Potency for muscarinic blockade

    34. Douglas L. Geenens, D.O. 2000

    35. Douglas L. Geenens, D.O. 2000 Clozaril Clozapine “Atypical” antipsychotic More effective in person’s who fail typical antipsychotic therapy At least nine different receptor affinities

    36. Douglas L. Geenens, D.O. 2000 Clozaril Clozapine One of the most complicated medications in psychopharmacology Can cause death via agranulocytosis Cost is typically $10,000.00 per year

    37. Douglas L. Geenens, D.O. 2000 Extrapyramidal Symptoms Dopamine Vs Acetylcholine Dopamine and Acetylcholine have a reciprocal relationship in the Nigrostriatal pathway. A delicate balance allows for normal movement.

    38. Douglas L. Geenens, D.O. 2000 Extrapyramidal Symptoms Dopamine Vs Acetylcholine Dopamine blockade: A relative increase in cholinergic activity causing EPS Those antipsychotics that have significant anti-ACH activity are therefore less likely to cause EPS

    39. Douglas L. Geenens, D.O. 2000 Extrapyramidal Symptoms Dopamine Vs Acetylcholine When high potency antipsychotics are chosen, we often prescribe anti-ACH medication like Cogentin, diphenhydramine, or Artane

    40. Douglas L. Geenens, D.O. 2000 Tardive Dyskinesia Associated with long-term use of antipsychotics (chronic dopamine blockade) Potentially irreversible involuntary movements around the buccal-lingual-oral area

    41. Douglas L. Geenens, D.O. 2000 Tardive Dyskinesia Attempt of decrease dose will initially exacerbate the movements Increasing the dose will initially decrease the movements

    42. Douglas L. Geenens, D.O. 2000 Neurological Side Effects: Dystonic Reactions: Uncoordinated spastic movements of muscle groups Trunk, tongue, face Akinesia: Decreased muscular movements Rigidity: Coarse muscular movement Loss of facial expression

    43. Douglas L. Geenens, D.O. 2000 Neurological Side Effects: Tremors: Fine movement (shaking) of the extremities Akathisia: Restlessness Pacing May result in insomnia Tardive Dyskinesia: Buccolinguo-masticalory syndrome Choreoathetoid movements

    44. Douglas L. Geenens, D.O. 2000 Neurological Side Effects of Neuroleptics

    45. Neurological Effects

    46. Extrapyramidal Effects

    47. Douglas L. Geenens, D.O. 2000 Neuroleptic Malignant Syndrome An idiosyncratic, life-threatening illness associated with antipsychotic therapy Clinical manifestations include hyperpyrexia autonomic instability, “board-like” rigidity

    48. Douglas L. Geenens, D.O. 2000 Neuroleptic Malignant Syndrome Resembles malignant hyperthermia associated with anesthesia Treatment involves Immediate discontinuation of antipsychotic Hydration Maintain vital functions Prescribe bromocriptine and dantrolene

    49. Douglas L. Geenens, D.O. 2000

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