**Core Concept**
Isoniazid-induced neuropathy, also known as peripheral neuropathy, is a common side effect of isoniazid, a first-line antitubercular medication. This condition arises due to the inhibition of a crucial enzyme involved in the metabolism of isoniazid, leading to the accumulation of toxic metabolites.

**Why the Correct Answer is Right**
Isoniazid-induced neuropathy is treated with pyridoxine (vitamin B6) because it is a cofactor for the enzyme glutamic acid decarboxylase, which is necessary for the metabolism of isoniazid. When pyridoxine levels are adequate, it prevents the accumulation of toxic metabolites that cause peripheral neuropathy. **Option B**, pyridoxine, is the correct choice because it is the only option that directly addresses the underlying pathophysiology of isoniazid-induced neuropathy.

**Why Each Wrong Option is Incorrect**
**Option A:** Thiamine (vitamin B1) is essential for carbohydrate metabolism and does not play a direct role in the metabolism of isoniazid.
**Option C:** Niacin (vitamin B3) is involved in redox reactions and energy metabolism but is not directly related to the treatment of isoniazid-induced neuropathy.
**Option D:** Riboflavin (vitamin B2) is important for energy production and can be found in various foods, but it is not the correct treatment for isoniazid-induced neuropathy.

**Clinical Pearl / High-Yield Fact**
It is essential to remember that pyridoxine deficiency can also cause other neurological symptoms, such as seizures and ataxia, and that patients on isoniazid should be advised to take pyridoxine supplements to prevent peripheral neuropathy.

**Correct Answer Line**
✓ Correct Answer: B. Pyridoxine.