**Core Concept**
Disulfiram is a medication used to treat chronic alcoholism by producing an acute sensitivity to ethanol (drinking alcohol). It works by inhibiting the enzyme acetaldehyde dehydrogenase, which is involved in the breakdown of alcohol. This inhibition leads to the accumulation of acetaldehyde, a toxic metabolite that causes unpleasant symptoms when alcohol is consumed.

**Why the Correct Answer is Right**
Disulfiram's mechanism of action does not directly affect blood pressure or cardiovascular system regulation. The correct answer, hypertension, is not a typical side effect of disulfiram administration, as it does not have a direct impact on the body's blood pressure control mechanisms. In contrast, disulfiram's inhibition of acetaldehyde dehydrogenase leads to the accumulation of acetaldehyde, which causes a range of symptoms, including flushing, headache, and nausea, when alcohol is consumed.

**Why Each Wrong Option is Incorrect**
**Option A:** Flushing is a well-known side effect of disulfiram administration in individuals who drink alcohol, caused by the accumulation of acetaldehyde.
**Option B:** Headache is also a common side effect of disulfiram, resulting from the toxic effects of acetaldehyde on the brain and nervous system.
**Option D:** Nausea is another symptom associated with disulfiram's mechanism of action, as the body attempts to eliminate the toxic acetaldehyde metabolite.

**Clinical Pearl / High-Yield Fact**
Disulfiram's effectiveness relies on the patient's ability to abstain from alcohol while taking the medication. A classic exam trap is to remember that disulfiram does not directly treat alcoholism but rather makes it more unpleasant for the patient to consume alcohol.

**✓ Correct Answer: C. Hypertension**