Carbonic anhydrase inhibitor should not be given in : a) Sulfonamide hypersensitivity b) Glaucoma c) High altitude sickness d) Metabolic acidosis e) COPD
**Core Concept**
Carbonic anhydrase inhibitors are a class of drugs used to treat various conditions, including glaucoma, epilepsy, and altitude sickness. They act by inhibiting the enzyme carbonic anhydrase, which is involved in the regulation of bicarbonate and hydrogen ion balance in the body.
**Why the Correct Answer is Right**
Carbonic anhydrase inhibitors should be avoided in conditions where the body is attempting to compensate for an acidic environment. At high altitude, the body naturally increases carbonic anhydrase activity to compensate for the decreased oxygen levels, making carbonic anhydrase inhibitors contraindicated. In metabolic acidosis, the body is already struggling to maintain acid-base balance, and inhibiting carbonic anhydrase would worsen the condition. Additionally, carbonic anhydrase inhibitors can cause hypokalemia, which can be particularly problematic in patients with COPD, as they often have underlying potassium imbalances.
**Why Each Wrong Option is Incorrect**
**Option A:** Sulfonamide hypersensitivity is not a direct contraindication for carbonic anhydrase inhibitors. While both classes of drugs share a similar chemical structure, they have distinct mechanisms of action and are not always cross-reactive.
**Option B:** Glaucoma is actually a condition for which carbonic anhydrase inhibitors are often prescribed, as they help reduce intraocular pressure.
**Option C:** This option selects both correct contraindications (high altitude sickness and COPD) and the incorrect option (metabolic acidosis).
**Clinical Pearl / High-Yield Fact**
Carbonic anhydrase inhibitors can cause a reversible decrease in plasma bicarbonate levels, leading to metabolic acidosis. This is especially relevant in patients with pre-existing kidney disease or those taking other medications that affect acid-base balance.
**✓ Correct Answer: B. ade. Carbonic anhydrase inhibitors should be avoided in high altitude sickness, metabolic acidosis, and COPD.**