Anti-inflammatory drugs

• Other pictures

<aside> 🔑

COX-1 vs COX-2

• COX-1 is constitutively expressed in various tissues and is involved in a number of "housekeeping functions" (eg, platelet aggregation, gastric mucosal protection, vascular homeostasis).
• COX-2 is an inducible enzyme that is released only during inflammation </aside>

Acetaminophen

Mechanism

• Reversibly inhibits cyclooxygenase, primarily in the CNS
• Inactivated peripherally

Clinical Use

• Antipyretic and analgesic but not anti-inflammatory.
• Preferred over aspirin in children with viral infections to avoid Reye syndrome.

Adverse Effects

• Overdose can lead to hepatic necrosis.
• NAPQI (toxic metabolite) depletes glutathione and forms toxic byproducts in liver, causing liver damage.

Antidote

• N-acetylcysteine → regenerates glutathione.

Aspirin

Mechanism

• Irreversibly inhibits cyclooxygenase (COX-1 and COX-2) through covalent acetylation→ ↓ TXA2 and prostaglandin synthesis.
• ↑ bleeding time but does not affect PT or PTT.
• Effect persists until new platelets are produced.

Clinical Use