An anti-hypeensive drug that causes positive coomb&;s test is
**Core Concept**
The question tests the student's knowledge of a rare but significant side effect of certain antihypertensive medications. The correct answer involves a drug that can cause a positive Coombs test, which is a laboratory finding indicating the presence of antibodies against red blood cells.
**Why the Correct Answer is Right**
The correct answer is **Penicillamine** (D). Penicillamine is a chelating agent used in the treatment of Wilson's disease and sometimes as an antihypertensive. It can cause a positive Coombs test due to its ability to induce the formation of antibodies against red blood cells. This is thought to occur through the formation of a complex between penicillamine and red blood cell antigens, leading to the activation of complement and the formation of immune complexes.
**Why Each Wrong Option is Incorrect**
* **Option A:** Lisinopril is an ACE inhibitor used in the treatment of hypertension. It does not cause a positive Coombs test.
* **Option B:** Clonidine is an alpha-2 adrenergic agonist used to treat hypertension. It does not have a known association with a positive Coombs test.
* **Option C:** Metoprolol is a beta-blocker used in the treatment of hypertension. It does not cause a positive Coombs test.
**Clinical Pearl / High-Yield Fact**
When prescribing penicillamine, it is essential to monitor patients for signs of hemolytic anemia, which can be triggered by a positive Coombs test. Additionally, patients on penicillamine should be warned about the potential for a positive Coombs test, which can affect blood transfusion compatibility.
**Correct Answer:** D. Penicillamine