Anticancer drug causing SIADH as an adverse effect is:
**Core Concept**
The question is testing the association between a specific anticancer drug and the development of the Syndrome of Inappropriate Antidiuretic Hormone Secretion (SIADH), a condition characterized by excessive release of antidiuretic hormone (ADH) leading to water retention and hyponatremia.
**Why the Correct Answer is Right**
Vincristine, a vinca alkaloid used in chemotherapy, is known to cause SIADH as a rare but significant adverse effect. This occurs due to the drug's ability to bind to microtubules in the posterior pituitary gland, disrupting the normal release mechanism of ADH. As a result, there is an inappropriate secretion of ADH, leading to water retention and dilutional hyponatremia.
**Why Each Wrong Option is Incorrect**
**Option A:** Cisplatin is a platinum-based chemotherapy drug that primarily causes nephrotoxicity and ototoxicity, but it is not commonly associated with SIADH.
**Option B:** Etoposide is a topoisomerase inhibitor used in various cancers, and while it has several adverse effects, SIADH is not a commonly reported one.
**Option C:** Cytarabine is a nucleoside analog used in leukemia treatment, and it can cause various adverse effects, but SIADH is not typically one of them.
**Clinical Pearl / High-Yield Fact**
It's essential to recognize that SIADH can be caused by various factors, including certain medications, tumors, and CNS disorders. In the context of chemotherapy, it's crucial to monitor patients for signs of SIADH, especially those receiving vincristine, and adjust their fluid management accordingly.
**Correct Answer:** C. Vincristine.