A 70-year-old male presented with lumps felt in axilla. On examination, axillary lymphadenopathy was noted. Biopsy was planned with the following HPE. No RS cells were seen. Flow cytometry revealed CD15 and CD30 negative. Following the histopathological confirmation of the disease, the patient was staed on chemotherapy regimen. After few days, the patient develops dysuria and urine examination was done. Supplementation of which drug could have prevented this condition?

**Core Concept**
The underlying condition in this case is a type of lymphoma, specifically a B-cell lymphoma variant, which is being treated with chemotherapy. However, the patient's symptoms suggest that the treatment is causing a specific side effect.

**Why the Correct Answer is Right**
The patient is likely experiencing a condition known as hemorrhagic cystitis, which is a common side effect of certain chemotherapeutic agents, particularly cyclophosphamide. This condition occurs due to the toxic effects of acrolein, a metabolite of cyclophosphamide, on the bladder mucosa. The use of a specific supplement, mesna, can help prevent this side effect by binding to acrolein and reducing its toxicity.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because mesna is a specific antidote for hemorrhagic cystitis caused by cyclophosphamide, and supplementation with this drug is the correct answer.
**Option B:** This option is incorrect because there is no evidence to suggest that supplementation with this drug would prevent hemorrhagic cystitis.
**Option C:** This option is incorrect because while hydration is an important aspect of preventing side effects from chemotherapy, it is not a specific supplement that would prevent hemorrhagic cystitis.
**Option D:** This option is incorrect because this drug is not typically used to prevent hemorrhagic cystitis.

**Clinical Pearl / High-Yield Fact**
When treating patients with cyclophosphamide, it is essential to consider the risk of hemorrhagic cystitis and to supplement with mesna to prevent this side effect. This is a classic example of a high-yield fact that can be remembered using the mnemonic "Cyclophosphamide-induced hemorrhagic cystitis: Mesna prevents it."

**Correct Answer:** A. Mesna.

✓ Correct Answer: C. Mesna