First Generation Anti-Psychotics: Mechanisms and Side Effects Typical/Conventional Anti-Psychotics - Examples: Haloperidol, Chlorpromazine ACh M1 antagonist - Block action of ACh throughout body (mouth, gut, eyes, brain) • Dry Mouth • Constipation • Blurred Vision • Cognitive Slowing Histamine H1 antagonist - Block action of Histamine in the brain • Weight Gain • Drowsiness alpha-1-adrenergic antagonist - Smooth muscle dilatation around arterioles -> less able to maintain blood pressure • Orthostatic Hypotension Mesolimbic Pathway - VTA -> limbic system • Decr Hallucinations • Decr Delusions Mesocortical Pathway - VTA -> Prefrontal Cortex • Apathy • Anhedonia • Decr Interest in social interactions Tuberoinfundibular Pathway - Hypothalamus -> Pituitary • Amenorrhea • Galactorrhea Nigrostriatal Pathway - Substantia Nigra -> Striatum -> Extrapyramidal Symptoms (EPS): • Tardive Dyskinesia - Abnormal asymmetric movements of face, tongue, and/or limbs caused by chronic dopamine blockade. Incidence of 5% per year, and can be irreversible • Drug induced Parkinsonism - Cogwheel rigidity, postural instability, resting tremor, bradykinesia/akinesia • Acute Dystonia - Muscular spasms of neck, eye, tongue/jaw • Akathisia - Feeling of motor restlessness #AntiPsychotics #FirstGeneration #Mechanisms #SideEffects #pharmacology #diagnosis #psychiatry
