Drug Monograph
Ibuprofen
ibuprofen — Motrin, Advil, Caldolor (IV)
Pharmacokinetic Profile
Half-Life
1.8–2.0 h (adults)
Metabolism
Hepatic: CYP2C9 (primary), CYP2C8 (secondary); oxidation and glucuronidation
Protein Binding
>99%
Bioavailability
~80% (oral); well absorbed
Volume of Distribution
~0.12–0.2 L/kg
Clinical Information
Drug Class
NSAID (nonselective COX-1/COX-2 inhibitor; propionic acid derivative)
Available Doses
Oral: 200 mg (OTC), 400 mg, 600 mg, 800 mg (Rx); suspension 100 mg/5 mL. IV: 800 mg/8 mL (Caldolor)
Route
Oral, Intravenous, Topical
Renal Adjustment
Avoid in severe renal impairment; use lowest dose for shortest duration if needed
Hepatic Adjustment
Avoid in severe hepatic impairment; use with caution in mild-to-moderate
Pregnancy
Avoid after 20 weeks gestation (NSAID class); contraindicated after 30 weeks (risk of premature ductus arteriosus closure and fetal renal impairment)
Lactation
Excreted in small amounts; generally compatible at recommended doses
Schedule / Legal Status
OTC (200 mg); Rx (400–800 mg oral; IV)
Generic Available
Yes (widely available)
Black Box Warning
Yes — CV thrombotic events and GI bleeding (NSAID class)
Indications
| Indication | Approved Population | Therapy Type | Status |
|---|---|---|---|
| Mild to moderate pain | Adults and children ≥6 months (oral); adults (IV) | Monotherapy or combination | FDA Approved |
| Fever reduction | Adults and children ≥6 months | Monotherapy | FDA Approved |
| Osteoarthritis (OA) | Adults | Monotherapy | FDA Approved |
| Rheumatoid arthritis (RA) | Adults | Monotherapy or adjunctive | FDA Approved |
| Primary dysmenorrhoea | Adults | Monotherapy | FDA Approved |
| Patent ductus arteriosus (PDA) closure | Premature neonates 500–1,500 g, ≤32 weeks GA | IV ibuprofen lysine (NeoProfen) | FDA Approved |
Ibuprofen is one of the most widely used NSAIDs globally, valued for its combined analgesic, anti-inflammatory, and antipyretic properties. At OTC doses (800–1,200 mg/day), it is indicated for minor pain and fever. At prescription doses (1,200–3,200 mg/day), it is used for inflammatory conditions including osteoarthritis and rheumatoid arthritis. Like all NSAIDs, ibuprofen carries FDA-mandated boxed warnings for cardiovascular thrombotic events and gastrointestinal bleeding.
Dosing
Dosing by Clinical Scenario
| Clinical Scenario | Starting Dose | Maintenance Dose | Maximum Dose | Notes |
|---|---|---|---|---|
| Adult OTC analgesia/antipyresis | 200–400 mg q4–6h | 200–400 mg q4–6h | 1,200 mg/day | Max 10 days for pain and 3 days for fever without medical advice (OTC labelling). Lowest effective dose for shortest duration |
| Adult Rx — mild to moderate pain | 400 mg q4–6h | 400–800 mg q6–8h | 3,200 mg/day | Take with food or milk to reduce GI irritation (Motrin PI). |
| Adult Rx — OA / RA | 400–800 mg TID–QID | Titrate to lowest effective dose | 3,200 mg/day | Response should be seen within 2 weeks; if no improvement, consider alternative. Well-controlled RA may need higher end of range (Motrin PI). |
| Adult Rx — primary dysmenorrhoea | 400 mg q4h | 400 mg q4–6h | 3,200 mg/day | Begin at onset of menses or pain; use for shortest duration needed. |
| Adult IV analgesia/antipyresis (Caldolor) | 400–800 mg q6h | 400–800 mg q6h | 3,200 mg/day | Infuse over at least 30 minutes. Patients must be well hydrated before administration (Caldolor PI). Caldolor PI (2024 revision) |
| Paediatric analgesia/antipyresis (≥6 months, oral) | 5–10 mg/kg q6–8h | 5–10 mg/kg q6–8h | 40 mg/kg/day | Dose by weight, not age. Use calibrated measuring device. Minimum interval 6 hours (Motrin Suspension PI). |
Clinical Pearl: OTC vs Prescription Dosing Spectrum
Ibuprofen spans a uniquely broad dosing range from OTC (max 1,200 mg/day) to full prescription anti-inflammatory doses (up to 3,200 mg/day). The risk profile changes substantially across this spectrum: GI and CV risks increase with dose and duration. The NSAID principle of “lowest effective dose for the shortest duration” is particularly important because many patients self-medicate at OTC doses before presenting for prescription management, potentially exceeding safe limits without medical awareness.
Pharmacology
Mechanism of Action
Ibuprofen is a nonselective, reversible inhibitor of both cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2), with approximately 2.5-fold greater potency against COX-1. By blocking COX-mediated conversion of arachidonic acid to prostaglandins (particularly PGE2, PGI2, and thromboxane A2), ibuprofen reduces inflammation, pain, and fever. COX-1 inhibition accounts for the gastrointestinal and platelet-related effects, while COX-2 inhibition mediates the anti-inflammatory and analgesic activity. Ibuprofen is a racemic mixture; the S(+)-enantiomer is the pharmacologically active form, while the R(−)-enantiomer undergoes slow, unidirectional chiral inversion (~60%) to the S(+)-form in vivo.
ADME Profile
| Parameter | Value | Clinical Implication |
|---|---|---|
| Absorption | Well absorbed orally; Tmax 1–2 h; bioavailability ~80%; linear PK up to 1,200 mg; food slows but does not reduce extent of absorption | Rapid onset supports use in acute pain; take with food to reduce GI irritation without compromising efficacy |
| Distribution | Vd ~0.12–0.2 L/kg; protein binding >99% (primarily albumin); does not cross the blood-brain barrier significantly | Very high protein binding creates potential for displacement interactions with other highly bound drugs (warfarin); small Vd reflects confinement to plasma compartment |
| Metabolism | Hepatic oxidation via CYP2C9 (primary) and CYP2C8 (secondary) to inactive hydroxyl and carboxyl metabolites; minor glucuronidation; R(−) to S(+) chiral inversion (~60%) | CYP2C9 poor metabolisers have elevated exposure and potential increased risk of GI toxicity (CPIC guideline). CYP2C9 inhibitors (fluconazole, voriconazole) increase ibuprofen exposure |
| Elimination | t½ 1.8–2.0 h; 45–79% excreted in urine within 24 h as metabolites; ~1% unchanged; excretion virtually complete within 24 h | Short half-life requires q4–8h dosing; no accumulation with normal renal function; no difference in half-life between adults and children (Motrin PI) |
Side Effects
Adverse reaction data are from the FDA prescribing information for Motrin (oral) and Caldolor (IV). NSAID class effects are well characterised across large clinical databases. Incidence rates reflect the NSAID class data cited in the FDA-approved labelling (1–10% range) and long-term observational studies for serious events.
1–10%Common (NSAID class, reported in 1–10% of patients)
| Adverse Effect | Incidence | Clinical Note |
|---|---|---|
| Dyspepsia / heartburn | 3–9% | Most common GI complaint; dose-related; take with food; consider gastroprotection if risk factors present (FDA PI) |
| Nausea | 3–9% | Dose-related; usually mild and self-limiting |
| Abdominal pain | 1–3% | Epigastric pain; investigate if persistent or associated with melena/haematemesis |
| Diarrhoea / constipation | 1–3% | GI motility effects from prostaglandin inhibition |
| Dizziness / headache | 3–9% | CNS effects; more common at higher doses |
| Peripheral oedema / fluid retention | 1–3% | Prostaglandin-mediated renal sodium retention; can worsen hypertension and heart failure (FDA PI) |
| Elevated liver enzymes | ~1% | Usually mild and transient; discontinue if persistent abnormalities develop |
| Rash / pruritus | 1–3% | Hypersensitivity reaction; discontinue if rash develops |
| Tinnitus | 1–3% | Dose-related; usually reversible on dose reduction |
SeriousSerious Adverse Effects (Regardless of Frequency)
| Adverse Effect | Estimated Frequency | Typical Onset | Required Action |
|---|---|---|---|
| GI bleeding, ulceration, perforation | ~1% at 3–6 months; 2–4% at 1 year | Any time; can occur without warning symptoms | Discontinue immediately. Prior PUD/GI bleeding increases risk >10-fold. Co-prescribe PPI for high-risk patients. Avoid concurrent aspirin, corticosteroids, anticoagulants (Motrin PI) |
| CV thrombotic events (MI, stroke) | NSAID class risk; may increase with dose and duration | Weeks to months; no latency period established | FDA Boxed Warning. Contraindicated peri-operatively in CABG surgery. Use lowest dose for shortest duration. Higher doses (>2,400 mg/day) associated with increased risk (EMA). Monitor CV symptoms (FDA PI) |
| Acute kidney injury | Uncommon; higher risk in elderly, volume-depleted, CKD, or concurrent nephrotoxins | Days to weeks | Monitor renal function. Prostaglandin inhibition reduces renal blood flow; highest risk in patients dependent on prostaglandins for renal perfusion (FDA PI) |
| Hypertension (new-onset or worsening) | Common (NSAID class) | Days to weeks | Monitor blood pressure. NSAIDs can blunt the effect of ACE inhibitors, ARBs, beta-blockers, and diuretics (FDA PI) |
| Serious skin reactions (SJS, TEN) | Very rare | Days to weeks | Discontinue at first sign of rash; do not rechallenge (FDA PI) |
| Heart failure exacerbation | NSAID class risk; ~2-fold increased hospitalisation | Weeks | Avoid in patients with established heart failure (NYHA II–IV) when possible. Fluid retention from prostaglandin inhibition can precipitate decompensation (CNT meta-analysis) |
| Aspirin-exacerbated respiratory disease (AERD) | Cross-reactivity in patients with aspirin triad | Minutes to hours | Contraindicated in patients with history of aspirin/NSAID-induced asthma, urticaria, or rhinitis. Can cause severe, potentially fatal bronchospasm (FDA PI) |
GI Risk Stratification
The Motrin PI notes that upper GI ulcers, gross bleeding, or perforation occur in approximately 1% of patients treated for 3–6 months and in 2–4% of patients treated for one year. Prior PUD/GI bleeding increases risk over 10-fold. Only one in five patients with a serious upper GI event is symptomatic beforehand. High-risk patients (age >65, prior PUD, concurrent corticosteroids/anticoagulants/aspirin, smoking, alcohol use) should receive gastroprotection with a PPI if ibuprofen is necessary.
Drug Interactions
Ibuprofen is metabolised primarily by CYP2C9 with minor CYP2C8 contribution. It is >99% protein bound (albumin) and inhibits prostaglandin synthesis, which underlies most of its clinically significant interactions — particularly with antihypertensives, anticoagulants, and renally-dependent drugs.
MajorLow-dose aspirin (cardioprotective)
MechanismIbuprofen competes for the NSAID-binding site on platelet COX-1, blocking aspirin’s irreversible acetylation and thus attenuating its antiplatelet effect
EffectLoss of aspirin’s cardioprotective effect; potentially increased cardiovascular events
ManagementTake ibuprofen at least 30 min after or 8 h before immediate-release low-dose aspirin. Consider acetaminophen as an alternative analgesic that does not interfere with aspirin’s antiplatelet effect. If an NSAID is required, consult prescriber regarding timing and agent selection (FDA advisory)
FDA AdvisoryMajorWarfarin and anticoagulants
MechanismCombined antiplatelet effect of ibuprofen (COX-1 inhibition) plus anticoagulant effect; high protein binding may displace warfarin; concurrent GI mucosal injury
EffectSignificantly increased risk of serious bleeding, including GI haemorrhage
ManagementAvoid concurrent use when possible; if required, monitor INR frequently and for signs of bleeding (FDA PI)
FDA PIMajorACE inhibitors / ARBs + diuretics (triple whammy)
MechanismNSAID reduces prostaglandin-dependent renal blood flow; concurrent RAAS blockade and diuresis compound the haemodynamic insult
EffectAcute kidney injury; also blunts antihypertensive efficacy of ACE inhibitors, ARBs, and beta-blockers
ManagementAvoid the “triple whammy” combination (NSAID + ACE/ARB + diuretic). Monitor renal function and BP. Ensure adequate hydration (FDA PI)
FDA PIMajorMethotrexate
MechanismNSAIDs reduce renal clearance of methotrexate; protein binding displacement may occur
EffectElevated methotrexate levels with potential for severe toxicity (pancytopenia, mucositis, hepatotoxicity)
ManagementUse with extreme caution at high-dose methotrexate; monitor methotrexate levels and renal function (FDA PI)
FDA PIModerateLithium
MechanismNSAIDs decrease renal lithium clearance by reducing prostaglandin-mediated renal blood flow
EffectIncreased lithium levels with risk of toxicity
ManagementMonitor lithium levels when starting, changing, or stopping ibuprofen (FDA PI)
FDA PIModerateSSRIs / SNRIs
MechanismSSRIs impair platelet serotonin uptake; combined with NSAID COX-1 inhibition, additive antiplatelet effects
EffectIncreased risk of GI bleeding beyond either agent alone
ManagementMonitor for signs of GI bleeding; consider gastroprotection with PPI in high-risk patients (FDA PI)
FDA PIMonitoring
- Blood pressureBaseline and within 2–4 weeks of starting
RoutineNSAIDs can raise BP and blunt antihypertensive therapy. Recheck BP after starting, especially in patients on ACE inhibitors, ARBs, or diuretics (FDA PI). - Renal function (BUN/Cr)Baseline; within 1–2 weeks of starting in at-risk patients
RoutineParticularly important in elderly, volume-depleted, CKD, concurrent ACE/ARB or diuretic therapy. Prostaglandin inhibition can acutely reduce renal perfusion (FDA PI). - CBCBaseline and periodically for chronic use
RoutineMonitor haemoglobin for occult GI blood loss; check platelets if bleeding concerns. Anaemia may develop from chronic GI microbleeding. - Hepatic functionBaseline for chronic Rx use; repeat if symptoms develop
Trigger-basedElevated transaminases reported in ~1% of patients. Discontinue if persistent abnormalities or hepatotoxicity symptoms develop (FDA PI). - GI symptomsAt each encounter
RoutineAsk about epigastric pain, dyspepsia, melena, haematemesis. Four out of five serious upper GI events occur without prior warning symptoms (Motrin PI). - CV symptomsThroughout treatment
RoutineInform patients about signs of MI (chest pain, SOB, weakness) and stroke (slurred speech, visual changes). Can occur even without prior CV symptoms (FDA Boxed Warning).
Contraindications & Cautions
Absolute Contraindications
- Known hypersensitivity to ibuprofen or other NSAIDs: Including aspirin-exacerbated respiratory disease (AERD) — asthma, nasal polyps, urticaria, or angioedema precipitated by aspirin or NSAIDs (FDA PI).
- Peri-operative use in CABG surgery: Contraindicated in the setting of coronary artery bypass graft surgery due to increased CV thrombotic events (FDA Boxed Warning).
- Active GI bleeding or peptic ulcer disease: NSAIDs exacerbate bleeding and impair healing of ulcers.
- Late pregnancy (≥30 weeks gestation): Risk of premature closure of the fetal ductus arteriosus and oligohydramnios from fetal renal impairment (FDA class NSAID warning, 2020).
Relative Contraindications (Specialist Input Recommended)
- Established heart failure (NYHA II–IV): NSAIDs can cause fluid retention and precipitate decompensation. Avoid when possible; if needed, use lowest dose for shortest duration with close monitoring.
- Chronic kidney disease (eGFR <30): Prostaglandin-dependent renal perfusion may be critically compromised. Avoid or use with extreme caution.
- Pregnancy 20–30 weeks gestation: FDA warning (2020) recommends avoiding NSAIDs during this period due to risk of oligohydramnios from fetal renal impairment.
Use with Caution
- Prior history of PUD/GI bleeding: >10-fold increased risk of GI bleeding. Co-prescribe PPI if NSAID use is necessary (Motrin PI).
- Elderly (≥65 years): Increased risk of all serious NSAID adverse events (GI, CV, renal). Use lowest effective dose.
- Concurrent anticoagulants, corticosteroids, SSRIs, or aspirin: Each independently increases GI bleeding risk with NSAIDs.
- Pre-existing hypertension or cardiovascular risk factors: NSAIDs can raise BP by 3–6 mmHg and increase CV event risk.
FDA Boxed Warning
Cardiovascular Thrombotic Events and Gastrointestinal Bleeding
All prescription NSAIDs, including ibuprofen, carry an FDA Boxed Warning for: (1) increased risk of serious cardiovascular thrombotic events, including myocardial infarction and stroke, which can be fatal — this risk may increase with duration of use and in patients with cardiovascular disease or risk factors; and (2) increased risk of serious gastrointestinal adverse events including bleeding, ulceration, and perforation of the stomach or intestines, which can be fatal and can occur at any time during use without warning symptoms — elderly patients are at greater risk. Ibuprofen is contraindicated for the treatment of peri-operative pain in the setting of CABG surgery.
Patient Counselling
Purpose of Therapy
Ibuprofen reduces pain, inflammation, and fever by blocking prostaglandins, natural chemicals that cause swelling and sensitise nerves to pain. Unlike acetaminophen, ibuprofen also treats inflammation, making it particularly useful for musculoskeletal pain, arthritis, and menstrual cramps.
How to Take
Take ibuprofen with food or milk to help protect the stomach. Swallow tablets whole with a full glass of water. Use the lowest dose that controls symptoms and do not use for longer than necessary. Do not exceed the recommended maximum dose. If using OTC ibuprofen, do not take for more than 10 days for pain or 3 days for fever without consulting a healthcare professional.
Stomach & Intestinal Safety
Tell patientIbuprofen can cause stomach ulcers and bleeding, which can happen without warning, especially with long-term use or higher doses. Taking it with food reduces stomach irritation but does not eliminate the risk. Do not take with other NSAIDs (naproxen, aspirin for pain) as this increases the risk.
Call prescriberImmediately if experiencing black or bloody stools, vomiting blood or material that looks like coffee grounds, or severe stomach pain.
Heart & Stroke Risk
Tell patientLike all NSAIDs, ibuprofen may slightly increase the risk of heart attack or stroke, particularly with long-term use or at higher doses. This risk exists even in people without prior heart problems.
Call prescriberImmediately if experiencing chest pain, shortness of breath, weakness on one side of the body, or slurred speech.
Aspirin Interaction
Tell patientIf taking low-dose aspirin for heart protection, ibuprofen can block aspirin’s protective effect. Take ibuprofen at least 30 minutes after or 8 hours before the daily aspirin dose. Consider using acetaminophen for pain instead, which does not interfere with aspirin.
Call prescriberBefore starting ibuprofen if currently taking daily aspirin for heart protection.
Pregnancy
Tell patientIbuprofen should be avoided during pregnancy, especially after 20 weeks. It can cause serious problems with the baby’s kidneys and heart, and can reduce the amount of fluid around the baby. Acetaminophen is the preferred pain reliever during pregnancy.
Call prescriberIf pregnant or planning to become pregnant while taking ibuprofen.
Sources
Regulatory (PI / SmPC)
- Motrin (ibuprofen) tablets prescribing information. McNeil Consumer Healthcare. FDA Label (2007)FDA-approved prescribing information for oral ibuprofen including dosing, PK data, warnings, and adverse reactions.
- Caldolor (ibuprofen injection) prescribing information. Cumberland Pharmaceuticals. Revised 2024. FDA Label (2024)Current FDA-approved label for IV ibuprofen including updated NSAID class boxed warning and dosing for IV administration.
- Motrin (ibuprofen) suspension prescribing information. McNeil Consumer Healthcare. FDA Label (2006)Regulatory source for pediatric ibuprofen dosing and suspension-specific PK data.
Key Clinical Trials / Meta-Analyses
- Nissen SE, Yeomans ND, Solomon DH, et al. Cardiovascular safety of celecoxib, naproxen, or ibuprofen for arthritis. N Engl J Med. 2016;375(26):2519–2529. doi:10.1056/NEJMoa1611593PRECISION trial — landmark randomised trial comparing cardiovascular safety of celecoxib, ibuprofen, and naproxen in arthritis patients.
- Coxib and traditional NSAID Trialists’ (CNT) Collaboration. Vascular and upper gastrointestinal effects of non-steroidal anti-inflammatory drugs: meta-analyses of individual participant data. Lancet. 2013;382(9894):769–779. doi:10.1016/S0140-6736(13)60900-9Definitive meta-analysis of >600 trials quantifying cardiovascular and GI risks of individual NSAIDs including ibuprofen.
Guidelines
- Antman EM, Bennett JS, Daugherty A, et al. Use of nonsteroidal antiinflammatory drugs: an update for clinicians — a scientific statement from the AHA. Circulation. 2007;115(12):1634–1642. doi:10.1161/CIRCULATIONAHA.106.181424AHA scientific statement providing clinical recommendations for NSAID use in patients with cardiovascular risk factors.
- Theken KN, Lee CR, Gong L, et al. Clinical Pharmacogenetics Implementation Consortium guideline for CYP2C9 and NSAIDs. Clin Pharmacol Ther. 2020;108(2):191–200. doi:10.1002/cpt.1830CPIC guideline for CYP2C9 genotype-guided NSAID dosing, including ibuprofen dose reductions for poor metabolisers.
Mechanistic / Basic Science
- Mazaleuskaya LL, Theken KN, Gong L, et al. PharmGKB summary: ibuprofen pathways. Pharmacogenet Genomics. 2015;25(2):96–106. doi:10.1097/FPC.0000000000000113Comprehensive pharmacogenomic pathway map of ibuprofen metabolism via CYP2C9/CYP2C8 and prostaglandin inhibition pathways.
Pharmacokinetics / Special Populations
- Davies NM. Clinical pharmacokinetics of ibuprofen: the first 30 years. Clin Pharmacokinet. 1998;34(2):101–154. doi:10.2165/00003088-199834020-00002Foundational PK review covering absorption, distribution, chiral inversion, metabolism, and elimination across populations.
- Ibuprofen. In: StatPearls. Treasure Island (FL): StatPearls Publishing; 2024. NCBI BookshelfContinuously updated clinical reference covering pharmacology, dosing, adverse effects, interactions, and monitoring.
- FDA Drug Safety Communication: FDA recommends avoiding use of NSAIDs in pregnancy at 20 weeks or later. October 2020. FDA.govFDA safety communication regarding NSAID-related oligohydramnios and fetal renal impairment after 20 weeks gestation.