**Core Concept:** Osteonecrosis is a condition characterized by the death of bone cells due to reduced blood supply, which can lead to fractures, pain, and deformities. IV drug administration can lead to complications due to drug toxicity or side effects.

**Why the Correct Answer is Right:** Salbutamol is a beta-2 agonist used for the treatment of asthma and bronchospasm. However, when given intravenously, it can cause bone marrow toxicity leading to osteonecrosis. This is due to the fact that IV salbutamol administration bypasses the liver first-pass effect, resulting in higher concentrations of the drug in the bloodstream. High salbutamol levels can damage bone marrow and lead to osteonecrosis.

**Why Each Wrong Option is Incorrect:**

A. **Option A (Caffeine):** Caffeine is a central nervous system stimulant and is primarily used as a psychoactive drug. It does not cause osteonecrosis when administered IV, as it does not have direct toxicity on bone marrow.

B. **Option B (Meperidine):** Meperidine is an opioid analgesic used for pain relief. However, its IV administration can lead to respiratory depression, central nervous system effects, and cardiac arrhythmias, but not osteonecrosis.

C. **Option C (Methotrexate):** Methotrexate is an immunosuppressive drug used for cancer chemotherapy. IV administration can cause severe toxicity due to high drug levels, affecting various organs and systems, but not specifically osteonecrosis.

D. **Option D (Salbutamol):** As explained earlier, IV salbutamol can cause bone marrow toxicity and osteonecrosis due to bypassing the liver first-pass effect.

**Clinical Pearl:** When administering IV medications, consider the potential for bypassing the liver first-pass effect, leading to higher systemic drug concentrations and associated complications. This is particularly important when using medications like salbutamol, which can cause osteonecrosis and other toxicities when not administered appropriately.