Coexistence of severe parkinsonism and tardive dyskinesia as side effects of neuroleptic therapy.
Neuroleptic-induced parkinsonism and tardive dyskinesia are caused, respectively, by blockade and supersensitivity of dopaminergic receptors in striatum, and represent contrasting syndromes with regard to clinical presentation and management. Two patients are described in whom parkinsonism and tardive dyskinesia developed and coexisted, with marked severity, during chronic neuroleptic administration. Pharmacologic manipulations accelerating nigrostriatal transmission improved akinesia but intensified the dyskinesias, whereas suppression had opposite effects. It is hypothesized that the coexistence of these two opposing side effects is due to simultaneous blockade and supersensitivity of two different subclasses of striatal dopaminergic receptors.
D000368:Aged; D014150:Antipsychotic Agents / Q000009:adverse effects*; D002230:Carbidopa / Q000494:pharmacology / Q000627:therapeutic use; D003342:Corpus Striatum / Q000187:drug effects; D003866:Depressive Disorder / Q000188:drug therapy; D004338:Drug Combinations; D004409:Dyskinesia, Drug-Induced / Q000150:complications / Q000188:drug therapy / Q000209:etiology*; D005260:Female; D006801:Humans; D007980:Levodopa / Q000494:pharmacology / Q000627:therapeutic use; D008297:Male; D008787:Metoclopramide / Q000494:pharmacology / Q000627:therapeutic use; D010302:Parkinson Disease, Secondary / Q000139:chemically induced* / Q000150:complications / Q000188:drug therapy; D011954:Receptors, Dopamine / Q000187:drug effects
D014150:Antipsychotic Agents; D004338:Drug Combinations; D011954:Receptors, Dopamine; D007980:Levodopa; D008787:Metoclopramide; D002230:Carbidopa