Schizophrenia Q 59
The nurse is aware that antipsychotic medications may cause which of the following adverse effects?
A. Increased production of insulin
B. Lower seizure threshold
C. Increased coagulation time
D. Increased risk of heart failure
Correct Answer: B. Lower seizure threshold
Antipsychotic medications exert an effect on brain neurotransmitters that lowers the seizure threshold and can, therefore, increase the risk of seizure activity. First-generation antipsychotics can also lower the seizure threshold, and chlorpromazine and thioridazine are more epileptogenic than others. First-generation antipsychotics are dopamine receptor antagonists (DRA) and are known as typical antipsychotics. They include phenothiazines (trifluoperazine, perphenazine, prochlorperazine, acetophenazine, triflupromazine, mesoridazine), butyrophenones (haloperidol), thioxanthenes (thiothixene, chlorprothixene), dibenzoxazepines (loxapine), dihydroxyindole (molindone), and diphenylbutylpiperidine (pimozide).
Option A: Antipsychotics don’t affect insulin production. First-generation antipsychotics (FGAs) are associated with significant extrapyramidal side effects. Anticholinergic adverse effects like dry mouth, constipation, urinary retention are common with low potency dopamine receptor antagonists like chlorpromazine, thioridazine. The action of H1 histamine blocking by First-generation antipsychotics causes sedation. Chlorpromazine is the most sedating, while fluphenazine, haloperidol, and pimozide are less sedating.
Option C: Antipsychotics don’t affect coagulation time. Thioridazine has a FDA boxed warning for sudden cardiac death. Low-potency FGAs, like chlorpromazine or thioridazine commonly cause orthostatic hypotension. This adverse effect caused by alpha-adrenergic block usually occurs when starting treatment, and patients often develop a tolerance. It is important to avoid treating hypotension with epinephrine. Leukopenia, thrombocytopenia, and blood dyscrasia are rare side effects of treatment with FGAs.
Option D: Heart failure isn’t an adverse effect of antipsychotic agents. Haloperidol can cause abnormal heart rhythm, ventricular arrhythmia, torsades de pointes, and even sudden death if injected intravenously. Other FGAs can cause prolongation of QTc interval, prolonged atrial and ventricular contraction, and other cardiac conduction abnormalities.