Drug causing maximum peripheral neuropathy is:
**Core Concept**
Peripheral neuropathy refers to damage or disease affecting peripheral nerves, which can be caused by various factors including metabolic disorders, infections, and certain medications. In this context, the question is asking about a specific drug that is known to cause significant peripheral neuropathy.
**Why the Correct Answer is Right**
The correct answer is **Isoniazid**. Isoniazid is a first-line antitubercular medication that can cause peripheral neuropathy due to its inhibitory effect on pyridoxine (vitamin B6) metabolism. Pyridoxine is essential for the synthesis of neurotransmitters, and its deficiency can lead to neurological symptoms, including peripheral neuropathy. The mechanism involves the depletion of pyridoxine stores, which impairs the synthesis of neurotransmitters, leading to nerve damage.
**Why Each Wrong Option is Incorrect**
* **Option A:** **Vincristine** is a chemotherapeutic agent that can cause neurotoxicity, but it is more commonly associated with central neuropathy rather than peripheral neuropathy.
* **Option B:** **Metformin** is an antidiabetic medication that is generally well-tolerated and not commonly associated with peripheral neuropathy.
* **Option C:** **Ethambutol** is another antitubercular medication that can cause optic neuritis, but it is not typically associated with peripheral neuropathy.
**Clinical Pearl / High-Yield Fact**
Isoniazid-induced peripheral neuropathy can be prevented or treated with pyridoxine supplementation, emphasizing the importance of monitoring for signs of neuropathy in patients on this medication.
**Correct Answer: C. Isoniazid**