First Generation Anti-Psychotics: Mechanisms and Side ...

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

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