Generic Name

Motrin

Mechanism

• Selective, reversible inhibition of cyclo‑oxygenase (COX) – primarily COX‑1 and COX‑2 enzymes, reducing prostaglandin synthesis.
• Decreases prostaglandin‑dependent vasodilation, vascular permeability, and nociceptor sensitization, thereby alleviating pain, lowering fever, and dampening swelling.
• Inhibits platelet aggregation by blocking thromboxane A₂ formation, leading to modest antiplatelet effects.

Pharmacokinetics

• Absorption: Rapid oral uptake; peak plasma concentrations 1–2 h after dosing.
• Bioavailability: 50–70 % (food reduces peak level by ~20 %).
• Distribution: Highly protein‑bound (~98 %).
• Metabolism: Hepatic via CYP2C9 and CYP3A4 to inactive metabolites.
• Elimination: 90 % renal (≈80 % as glucuronide conjugates); half‑life ≈2 h (shorter in young adults, longer in elderly).
• Drug interactions: CYP3A4 inducers (e.g., rifampin) decrease plasma ibuprofen; CYP2C9 inhibitors (e.g., fluconazole) increase exposure.

Indications

• Mild to moderate musculoskeletal pain (e.g., osteoarthritis, acute injury).
• Meningitis‑related headache (followed by antibiotic therapy).
• Dental pain post‑extraction.
• Premenstrual syndrome symptomatic relief.
• Management of febrile illnesses in children > 6 months.
• CEST for short‑term rheumatologic and inflammatory disorders.

Contraindications

• Known hypersensitivity to ibuprofen or other NSAIDs.
• Active peptic ulcer or GI bleeding.
• Severe hepatic or renal impairment (use with caution).
• Pregnancy: third trimester contraindicated; first trimester discouraged.
• Cardiovascular disease: increased risk of ischemic events with long‑term use.
• Use caution in asthma patients (possible bronchospasm).
• Children under 6 months: contraindicated.

Dosing

• Adults: 200‑400 mg PO q6‑8 h PRN. Do not exceed 1200 mg/24 h (or 2400 mg/24 h with physician supervision).
• Elderly: Initiate at lower doses (200 mg PO q8 h) due to reduced clearance.
• Children (≥6 mo): 5‑10 mg/kg PO every 6‑8 h; maximum 40 mg/kg/24 h.
• Extended‑release formulations (e.g., Motrin® XR) offer 24‑h dosing for chronic pain.
• Take with food or a full glass of water to minimize GI irritation.

Adverse Effects

Common (≥5 %)
• Gastro‑intestinal upset (nausea, dyspepsia, belching)
• Headache, dizziness
• Mild rash or pruritus

Serious (≤1 %)
• Upper GI bleeding, ulcer perforation
• Renal impairment (acute tubular necrosis, oliguria)
• Hepatic dysfunction (ALT/AST ↑)
• Hypersensitivity reactions (angioedema, anaphylaxis)
• Cardiac events (hypertension, myocardial infarction, congestive heart failure)

Monitoring

• Baseline: CBC, CMP, urinalysis, BP, eGFR.
• Periodic: eGFR every 3–6 months in >65 yr or CKD pts; monitor hemoglobin/hematocrit for bleeding.
• Liver enzymes if symptoms of hepatotoxicity (jaundice, malaise).
• Blood pressure monthly if on long‑term therapy.

Clinical Pearls

• “Trojan‐horse” for locale pain: ibuprofen’s ability to cross the blood‑brain barrier makes it effective for headaches and osteoarthritic joint pain.
• Avoid rotavirus‑infected children if pubertal; risk of intussusception is >100× higher.
• COX‑7 ocular (rare) side‑effects: solitary cases of well‑tolerated eye irritation; not dose‑related.
• Combine with antacids (e.g., ranitidine) only if concomitant aspirin therapy is required; otherwise use PPI for high‑risk patients.
• Drug‑drug caution: Concomitant use of Angiotensin‑Converting Enzyme inhibitors on a low dose of ibuprofen can worsen renal function; reduce ACE inhibitor dose or monitor SID.
• Therapeutic drug monitoring: For patients with CYP2C9 polymorphisms (e.g., *3 allele) consider lower dosing due to slower metabolism.
• Follow‑up: At 2‑4 weeks after initiating therapy to assess pain relief and check for GI symptoms.

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• *Prepared by the Pharmacology Reference Team. All data are up to date as of 2026 and based on peer‑reviewed literature.*