A 30 year old pregnant woman develops tuberculosis. Which of the following antitubercular drugs should not be used?
**Core Concept**
During pregnancy, the safety and efficacy of medications are carefully evaluated to minimize risks to the mother and fetus. Antitubercular drugs are no exception, and their use is guided by the potential benefits to the mother versus the potential risks to the fetus.
**Why the Correct Answer is Right**
Ethambutol (option A) is a first-line antitubercular medication, but it is known to cross the placenta and can cause optic neuritis, leading to visual disturbances in the fetus. This makes it a less desirable choice during pregnancy. In contrast, other antitubercular medications like isoniazid, rifampicin, and pyrazinamide are generally considered safe during pregnancy, although their use is still carefully monitored.
**Why Each Wrong Option is Incorrect**
* **Option B:** Isoniazid is a first-line antitubercular medication and is considered safe during pregnancy, although its use is monitored for potential side effects like peripheral neuropathy.
* **Option C:** Pyrazinamide is another first-line antitubercular medication that is generally considered safe during pregnancy, although its use may be associated with hepatotoxicity.
* **Option D:** Rifampicin is a first-line antitubercular medication and is considered safe during pregnancy, although its use may be associated with potential side effects like hepatitis.
**Clinical Pearl / High-Yield Fact**
When using antitubercular medications during pregnancy, it is essential to weigh the benefits of treatment against the potential risks to the fetus. Regular monitoring of the mother and fetus, as well as careful selection of medications, can minimize risks and ensure effective treatment.
**Correct Answer:** A.