Ibuprofen

Category: pharmacological

Aliases: Advil, Motrin, Brufen

Pharmacological Mechanism

Reversible non-selective arachidonic acid cascade COX inhibitor. Reduces prostaglandin synthesis → analgesia, anti-inflammation, antipyresis. Reversibility means antiplatelet effect is dose-dependent + reversible (unlike aspirin's irreversible acetylation).

Half-Life (t½)

PO: 1.9h, IV: 1.9h

Dosing Guidelines

PO: Typical 400 mg (Range: 200–800 mg)
IV: Typical 400 mg (Range: 200–800 mg)
TD: Typical 400 mg (Range: 200–800 mg)

Target Organ Systems

immune-hematologic

Interactions

Acetaminophen (synergistic): Complementary mechanisms — APAP + ibuprofen outperforms either alone for post-op/dental pain.
Apixaban (caution): Additive GI bleed risk; avoid chronic co-use. [Holbrook 2005]
Aspirin (caution): Ibuprofen may block aspirin's COX-1 acetylation site if taken within 2 h prior — reduces cardioprotective effect.
Dabigatran (caution): Additive GI bleeding; avoid chronic combination. [Holbrook 2005]
Rivaroxaban (caution): Additive GI bleed risk; avoid chronic co-use. [Holbrook 2005]
Warfarin (caution): Plasma protein-binding displacement at HSA. Chan 1989 (PMID:2724076) equilibrium dialysis: free warfarin 5–9% with ibuprofen vs 2.5–6% baseline. Low-end Δfu = (5 − 4.25)/4.25 ≈ 0.18. In-vitro magnitude; clinical effect smaller. Dominant clinical concern is COX-1/platelet additive bleed risk + GI mucosal injury, not displacement.

Pathways It Modulates

Arachidonic acid cascade (inhibitor) — COX-1 + COX-2 (reversible)
Bradykinin / kallikrein-kinin system (inhibitor) — COX-1/2

Chemical Identifiers

PubChem CID: 3672
Formula: C13H18O2
Molecular weight: 206.28 g/mol
InChIKey: HEFNNWSXXWATRW-UHFFFAOYSA-N
SMILES: CC(C)CC1=CC=C(C=C1)C(C)C(=O)O