Chapter 29: Antipsychotic Agents & Lithium
Which statement about the pathophysiologic basis of schizophrenia is most accurate?
(A) All clinically effective antipsychotic drugs have high affinity for dopamine D2 receptors
(B) Dopamine receptor-blocking drugs are used to alleviate psychotic symptoms in parkinsonism
(C) Drug-induced psychosis can occur without activation of brain dopamine receptors
(D) Serotonin receptors are present at lower than normal levels in the brains of untreated schizophrenics
(E) The clinical potency of olanzapine correlates well with its dopamine receptor-blocking activity
Although most older antipsychotic drugs block D2 receptors, this action is not a requirement for antipsychotic action. Aripiprazole, clozapine, and most newer second-generation drugs have a very low affinity for such receptors, but a high affinity for serotonin 5-HT2 receptors. There are no reports of decreased serotonin receptors in the brains of schizophrenics. The CNS effects of phencyclidine (PCP) closely parallel an acute schizophrenic episode, but PCP has no actions on brain dopamine receptors. Dopamine receptor blockers cause extrapyramidal dysfunction. The answer is C.
Trifluoperazine was prescribed for a young male patient diagnosed as suffering from schizophrenia. He complains about the side effects of his medication. Which of the following is not likely to be on his list?
Phenothiazines such as trifluoperazine cause sedation and are antagonists at muscarinic and α adrenoceptors. Postural hypotension, blurring of vision, and dry mouth are common autonomic adverse effects, as is constipation. Effects on the male libido may result from increased prolactin or from increased peripheral conversion of androgens to estrogens. The answer is C.
Which statement concerning the adverse effects of antipsychotic drugs is accurate?
(A) Acute dystonic reactions occur commonly with olanzapine
(B) Akathisias due to antipsychotic drugs are managed by increasing the drug dose
(C) Blurring of vision and urinary retention are common adverse effects of haloperidol
(D) Retinal pigmentation is a dose-dependent toxic effect of thioridazine
(E) The late-occurring choreoathetoid movements caused by conventional antipsychotic drugs are alleviated by atropine
Olanzapine has minimal dopamine receptor–blocking action and is unlikely to cause acute dystonias. Muscarinic blockers such as atropine exacerbate tardive dyskinesias. Akathisias (uncontrollable ...