Red cells are caught as innocent bystanders in the reaction between drug and antibodies against that drug, and develops hemolysis. Which drug is responsible for such a reaction?
**Core Concept**
The question is testing the concept of drug-induced hemolytic anemia, where red blood cells are destroyed due to an immune reaction triggered by a medication. This condition occurs when the immune system mistakenly identifies the drug or its metabolites as foreign and produces antibodies against them.
**Why the Correct Answer is Right**
The correct answer is a penicillin, which is a classic example of a drug that can cause hemolytic anemia through an immune-mediated mechanism. When penicillin is administered, it is metabolized into a compound called penicilloyl, which can bind to red blood cells and make them appear foreign to the immune system. As a result, the immune system produces antibodies against the penicilloyl group, leading to the destruction of red blood cells. This reaction is known as a type II hypersensitivity reaction.
**Why Each Wrong Option is Incorrect**
* **Option A:** Methyldopa is an antihypertensive medication that can cause a type II hypersensitivity reaction, but it is not as strongly associated with hemolytic anemia as penicillin.
* **Option B:** Aspirin is not typically associated with hemolytic anemia, although it can cause other types of hemolytic anemia, such as glucose-6-phosphate dehydrogenase (G6PD) deficiency.
* **Option C:** Cephalosporins are a class of antibiotics that are structurally related to penicillin and can also cause hemolytic anemia through a similar mechanism.
**Clinical Pearl / High-Yield Fact**
To remember the classic drugs associated with hemolytic anemia, use the mnemonic "PENICILLIN": Penicillin, Erythromycin, Nalidixic acid, and Cephalosporins. This will help you recall the most common culprits behind this condition.
**Correct Answer:** C. Cephalosporins