Risperidone

Higher and more consistent than any other commonly prescribed atypical antipsychotic. Causes galactorrhea, amenorrhea, sexual dysfunction, gynecomastia, and with chronic elevation, reduced bone mineral density. Screen for symptoms proactively at every visit. Measure prolactin at baseline in higher-risk patients (pediatrics, fertility concerns, bone risk) and whenever symptoms emerge. Ask about symptoms directly because patients often do not volunteer them.

Includes akathisia, dystonia, parkinsonism (tremor, rigidity, bradykinesia), and with long-term use, tardive dyskinesia. Risk increases with dose, particularly above 4-6mg. The lack of intrinsic anticholinergic activity (unlike olanzapine) means there is no built-in EPS buffer.

Less than olanzapine or clozapine, but clinically significant. Metabolic monitoring (weight, glucose, lipids) is required, consistent with guidelines for all atypical antipsychotics.

Alpha-1 mediated. Primarily during initiation and titration. Slow titration from a low starting dose mitigates risk. Clinically relevant in elderly patients.

Less sedating than olanzapine or quetiapine but present, particularly at higher doses. Bedtime dosing preferred.

Risperidone causes modest QTc prolongation. Less concerning than ziprasidone but should be considered in patients with pre-existing QTc prolongation or those on other QTc-prolonging medications.

Positioned between aripiprazole (lowest metabolic risk) and olanzapine (highest). Weight gain, glucose elevation, and lipid changes occur and require standard antipsychotic metabolic monitoring.