Arthralgia is commonly caused by which ATT drug?
**Core Concept:**
Arthralgia is a type of joint pain that is one of the common side effects of certain medications, particularly those that belong to the Anti-Tuberculosis (ATT) drug group. The primary purpose of ATT is to treat tuberculosis (TB) by targeting and inhibiting the growth of Mycobacterium tuberculosis, a bacterium that causes TB disease.
**Why the Correct Answer is Right:**
The correct answer, D-Isoniazid, belongs to the isoniazid group of antitubercular drugs. It is a potent inhibitor of mycobacterial enzymes and is considered the cornerstone of TB treatment. Isoniazid prevents the formation of mycobacterial cell wall, which leads to the inhibition of bacterial growth and ultimately results in the relief of arthralgia caused by the drug.
**Why Each Wrong Option is Incorrect:**
A. Option A (Pyrazinamide) is also an antitubercular drug, but it does not cause arthralgia. It is an anti-microbial drug that works synergistically with other drugs in the ATT regimen to eradicate TB.
B. Option B (Ethambutol) is another essential drug in the ATT regimen, but it does not cause arthralgia. It works by inhibiting mycolic acid synthesis in the mycobacterial cell wall.
C. Option C (Rifampicin) is an essential drug in the ATT regimen, but it does not cause arthralgia. It is a potent inhibitor of bacterial RNA synthesis and is essential for TB treatment.
**Clinical Pearl:**
Understanding the pharmacology and mechanism of action of ATT drugs is crucial for recognizing and managing the drug-induced side effects like arthralgia. In case of suspected drug-induced arthralgia, stopping the offending drug is key, and treatment with non-steroidal anti-inflammatory drugs (NSAIDs) can be started for pain relief.