All of the following are predictable adverse effects of treatment with phenothiazines such as chlorpromazine, EXCEPT:
**Core Concept**
Phenothiazines, like chlorpromazine, are a class of antipsychotic medications that act as dopamine D2 receptor antagonists. Their therapeutic effects are largely due to central nervous system blockade, but they also have various side effects due to their pharmacological properties.
**Why the Correct Answer is Right**
Chlorpromazine and other phenothiazines can cause a range of predictable adverse effects, including extrapyramidal symptoms (EPS), such as dystonia, akathisia, and parkinsonism. These effects are due to the blockade of dopamine D2 receptors in the nigrostriatal pathway, which disrupts normal motor control. Additionally, phenothiazines can cause hypotension due to their alpha-adrenergic blocking activity, leading to vasodilation and a decrease in blood pressure.
**Why Each Wrong Option is Incorrect**
**Option A:** Not a predictable adverse effect of phenothiazines.
**Option B:** A common side effect of phenothiazines, particularly at high doses.
**Option C:** Not a typical side effect of phenothiazines.
**Option D:** A predictable adverse effect of phenothiazines, particularly due to their anticholinergic activity.
**Clinical Pearl / High-Yield Fact**
Remember that phenothiazines can cause a range of extrapyramidal symptoms due to their dopamine D2 receptor blockade, and that these effects can be mitigated with anticholinergic medications or by adjusting the dosage.
**Correct Answer: C.**