Methotrexate is used in high doses in –
**Core Concept**
Methotrexate is a **chemotherapeutic agent** and an **immune system suppressant**. It is used in the treatment of various cancers and autoimmune diseases. The dosage of methotrexate varies depending on the condition being treated.
**Why the Correct Answer is Right**
High-dose methotrexate is used in the treatment of certain types of cancer, such as **osteosarcoma**. This is because high doses are needed to achieve adequate **cytotoxic effects** on cancer cells.
**Why Each Wrong Option is Incorrect**
**Option A:** Not enough information to determine correctness.
**Option B:** Not enough information to determine correctness.
**Option C:** Not enough information to determine correctness.
**Option D:** Not enough information to determine correctness.
**Clinical Pearl / High-Yield Fact**
Methotrexate is a **folate antagonist**, and its high-dose use requires **leucovorin rescue** to prevent toxicity.
**Correct Answer:** D. Osteosarcoma