**Question:** NSAIDS cause gastric ulcer because-

A. Reduced production of mucus
B. Increased gastric acid secretion
C. Direct cytotoxicity to gastric mucosa
D. Inhibition of cyclooxygenase pathway

**Core Concept:** Nonsteroidal anti-inflammatory drugs (NSAIDs) are a class of medications used to relieve pain, inflammation, and fever. They work by inhibiting the cyclooxygenase (COX) pathway, which leads to reduced production of prostaglandins. Prostaglandins play a crucial role in protecting the gastric mucosa from damage by maintaining its integrity and inhibiting gastric acid secretion.

**Why the Correct Answer is Right:** NSAIDs cause gastric ulcers primarily due to the inhibition of the COX pathway, specifically COX-1 and COX-2 enzymes. This inhibition reduces the production of prostaglandins, which are essential for maintaining the integrity of the gastric mucosa and regulating gastric acid secretion.

**Why Each Wrong Option is Incorrect:**

A. Reduced production of mucus (Option A) is not the primary mechanism by which NSAIDs induce gastric ulcers. While mucus production is important for ulcer protection, it is the inhibition of COX enzymes that directly damages the gastric mucosa.

B. Increased gastric acid secretion (Option B) is not the primary mechanism of NSAID-induced gastric ulcers. NSAIDs do not directly impact gastric acid secretion; however, the reduced production of prostaglandins due to COX inhibition contributes to the overall increase in gastric acidity and ulcer formation.

C. Direct cytotoxicity to gastric mucosa (Option C) is a consequence of the primary mechanism of NSAIDs causing gastric ulcers. The reduced production of prostaglandins due to COX inhibition leads to impaired mucosal defense mechanisms, making the gastric mucosa more susceptible to damage.

D. Inhibition of the COX pathway (Option D) is the primary mechanism by which NSAIDs cause gastric ulcers. This inhibition reduces the production of prostaglandins, which in turn affects gastric mucosal defense mechanisms and increases the risk of ulcer formation.

**Clinical Pearl:** To minimize the risk of NSAID-induced gastric ulcers, consider prescribing proton pump inhibitors (PPIs) or H2-receptor antagonists along with NSAIDs, as these medications can help maintain gastric mucosal defense mechanisms and reduce gastric acid secretion. This co-medication is particularly important in high-risk patients, such as those with a history of prior ulcer disease, elderly individuals, or those with concomitant corticosteroid use.