## Atypical Antipsychotic Side Effects: Risperidone Profile ### Mechanism of Risperidone's Adverse Effects Risperidone is an atypical antipsychotic with dopamine D₂ and serotonin 5-HT₂A receptor antagonism. Its side effect profile differs markedly from typical antipsychotics. ### Common Side Effects of Risperidone | Side Effect | Mechanism | Clinical Relevance | |---|---|---| | **Hyperprolactinemia** | D₂ blockade in tuberoinfundibular pathway | Galactorrhea, sexual dysfunction, amenorrhea | | **Orthostatic hypotension** | α₁-adrenergic blockade | Dizziness, syncope, falls (especially early) | | **Weight gain & increased appetite** | 5-HT₂C antagonism, H₁ blockade | Metabolic syndrome risk | | **Extrapyramidal side effects** | D₂ blockade in nigrostriatal pathway | Akathisia, dystonia, parkinsonism | | **Sedation** | H₁ histamine blockade | Dose-dependent, usually transient | ### Why Hypertension is NOT a Recognized Effect **Key Point:** Risperidone causes **orthostatic hypotension** (postural drop), NOT sustained hypertension. The α₁-adrenergic blockade leads to vasodilation and reduced peripheral vascular resistance, resulting in **hypotension**, particularly upon standing. **High-Yield:** Atypical antipsychotics like risperidone, olanzapine, and quetiapine are associated with **hypotension**, not hypertension. Hypertension is not a characteristic adverse effect of risperidone and would be an unusual or coincidental finding unrelated to the drug. ### Clinical Pearl The patient in this vignette exhibits classic risperidone toxicity: hyperprolactinemia (galactorrhea, sexual dysfunction) and metabolic effects (weight gain). Orthostatic hypotension would also be expected, especially if dosing was recent or increased. Hypertension would suggest either an unrelated comorbidity or a different drug class (e.g., stimulants, some typical antipsychotics in rare cases).
Sign up free to access AI-powered MCQ practice with detailed explanations and adaptive learning.