COMBOGESIC IV
Clinical safety rating
cautionComprehensive clinical and safety monograph for COMBOGESIC IV (COMBOGESIC IV).
Combination of acetaminophen (paracetamol) and ibuprofen. Acetaminophen: Weak COX inhibition in CNS, analgesic and antipyretic. Ibuprofen: Non-selective COX-1/COX-2 inhibition, anti-inflammatory, analgesic, antipyretic.
| Metabolism | Acetaminophen: Hepatic via conjugation (glucuronidation, sulfation) and CYP2E1 (minor) to reactive metabolite NAPQI. Ibuprofen: Hepatic via CYP2C9 and CYP2C8 to inactive metabolites. |
| Excretion | Renal: 90% as glucuronide conjugates and unchanged drug for paracetamol; biliary: 10% for paracetamol. For tramadol: renal 90% (unchanged and metabolites), fecal 10%. |
| Half-life | Paracetamol: 1.5-3 hours; tramadol: 6 hours (active metabolite M1: 7-9 hours). Clinical context: Extended half-life in hepatic impairment (cirrhosis) and elderly; requires dose adjustment. |
| Protein binding | Paracetamol: 10-25% bound to albumin; tramadol: 20% bound to albumin; active metabolite M1: negligible binding. |
| Volume of Distribution | Paracetamol: 0.9 L/kg; tramadol: 2.7 L/kg (wide distribution into tissues). Clinical meaning: High Vd for tramadol indicates extensive tissue distribution. |
| Bioavailability | IV: 100% for both components. Oral: Paracetamol 85-90%; tramadol 75% (first-pass metabolism). Not applicable for IM/SC routes. |
| Onset of Action | IV: Paracetamol onset within 5 minutes; tramadol onset within 5-10 minutes. Peak effect at 1 hour for both. |
| Duration of Action | Paracetamol: 4-6 hours (analgesia); tramadol: 4-6 hours (analgesia). Clinical notes: Duration may be prolonged with high doses or in renal impairment. |
| Molecular Weight | Paracetamol: 151.16 Da; Ibuprofen: 206.28 Da |
1 vial (1000 mg paracetamol + 60 mg codeine phosphate) IV infusion over 15 minutes, every 4-6 hours as needed, max 4 vials per day.
| Dosage form | SOLUTION |
| Renal impairment | eGFR 30-50 mL/min: administer every 6 hours; eGFR <30 mL/min: not recommended; dialysis: contraindicated. |
| Liver impairment | Child-Pugh A: no adjustment; Child-Pugh B: reduce dose by 50% or extend interval; Child-Pugh C: contraindicated. |
| Pediatric use | Children >12 years and ≥50 kg: same as adult dose; <12 years or <50 kg: not recommended due to codeine; use alternative analgesic. |
| Geriatric use | Initiate at lowest effective dose; monitor for respiratory depression and hypotension; consider reduced dose or extended interval due to age-related clearance decline. |
| 1st trimester | Avoid; combination contains NSAID (ibuprofen) which is associated with increased risk of miscarriage and cardiac defects. |
| 2nd trimester | Caution; ibuprofen may cause oligohydramnios and premature ductus arteriosus constriction; use lowest effective dose for shortest duration. |
| 3rd trimester | Avoid; NSAIDs contraindicated due to risk of premature closure of ductus arteriosus and oligohydramnios. Paracetamol is safer alternative. |
Clinical note
Comprehensive clinical and safety monograph for COMBOGESIC IV (COMBOGESIC IV).
| Placental transfer | Both paracetamol and ibuprofen cross the placenta. Ibuprofen transfer is approximately 1% of maternal dose; paracetamol crosses readily. |
| Breastfeeding | Paracetamol and ibuprofen are excreted into breast milk in low amounts. Ibuprofen levels are low and considered compatible; paracetamol also safe. However, use lowest effective dose for shortest duration. Monitor infant for potential effects (e.g., rash, drowsiness). |
| Lactation Rating | L2 (Safer; paracetamol and ibuprofen compatible) |
| Teratogenic Risk | First trimester: Avoid combination acetaminophen/NSAIDs due to potential cardiovascular and neural tube defects with NSAIDs; acetaminophen considered relatively safe but limit use. Second trimester: NSAIDs associated with oligohydramnios and fetal renal effects; acetaminophen safe at therapeutic doses. Third trimester: NSAIDs contraindicated due to risk of premature ductus arteriosus closure, oligohydramnios, and neonatal renal impairment; acetaminophen preferred. |
| Fetal Monitoring | Monitor maternal blood pressure, renal function (creatinine, BUN), and signs of gastrointestinal bleeding; fetal monitoring for amniotic fluid index (oligohydramnios) and ductus arteriosus Doppler if used beyond 20 weeks gestation. Assess fetal growth if prolonged use. |
| Fertility Effects | NSAIDs may impair female fertility by inhibiting prostaglandin synthesis, affecting ovulation and implantation; reversible upon discontinuation. Acetaminophen not associated with fertility impairment. No documented effect on male fertility. |
■ FDA Black Box Warning
Risk of severe hepatic injury with acetaminophen; do not exceed maximum daily dose (4 g/day).
| Serious Effects |
Hypersensitivity to paracetamol, ibuprofen, or any excipientActive peptic ulcer disease or gastrointestinal bleedingSevere hepatic impairment (Child-Pugh C)Severe renal impairment (eGFR <30 mL/min)History of asthma, urticaria, or allergic-type reactions after taking aspirin or other NSAIDsThird trimester of pregnancyCerebrovascular bleeding or other bleeding disordersConcurrent use of other NSAIDs or anticoagulants (unless supervised)
| Precautions | Hepatotoxicity (acetaminophen overdose), GI bleeding/ulceration (ibuprofen), renal impairment, cardiovascular thrombotic events (ibuprofen), anaphylactic reactions, masking of infection signs. |
| Food/Dietary | Concurrent food intake does not affect IV administration. However, patients should avoid alcohol consumption due to increased risk of hepatotoxicity from paracetamol and gastrointestinal bleeding from ibuprofen. No other specific food interactions are known. |
| Clinical Pearls | COMBOGESIC IV is a fixed-dose combination of paracetamol (acetaminophen) 1000 mg and ibuprofen 300 mg per 100 mL solution. Administer only as a single intravenous infusion over 15 minutes. Do not administer if the solution contains particulates or is discolored. Avoid use in patients with severe hepatic impairment (Child-Pugh C), severe renal impairment (eGFR <30 mL/min/1.73m²), active peptic ulcer disease, or history of aspirin allergy. Monitor for signs of hepatotoxicity (paracetamol) and renal toxicity (ibuprofen). Contraindicated in patients with severe heart failure (NYHA III/IV) or preoperative CABG surgery. Use lowest effective dose for shortest duration. Not recommended for patients <18 years due to lack of safety data. Contains ibuprofen; risk of serious GI adverse events including bleeding, ulceration, and perforation, especially in elderly. Do not exceed 4 doses (4000 mg paracetamol/1200 mg ibuprofen) per day. Concomitant use of other NSAIDs or paracetamol-containing products is contraindicated. |
| Patient Advice | This medication is given intravenously and is not for self-administration. · Inform your healthcare provider if you have a history of liver or kidney disease, stomach ulcers, bleeding disorders, heart disease, high blood pressure, or asthma. · Avoid taking any additional acetaminophen (paracetamol) or NSAIDs (e.g., ibuprofen, naproxen) while receiving this medication. · Report any signs of allergic reaction (rash, itching, swelling, difficulty breathing), stomach pain, black or bloody stools, vomiting blood, unusual bruising or bleeding, yellowing of skin or eyes, dark urine, or severe fatigue. · Do not consume alcohol while being treated with this medication; alcohol increases the risk of liver damage and stomach bleeding. · This medication may cause dizziness or drowsiness; avoid driving or operating machinery if affected. · Tell your doctor about all medications you are taking, including prescription, over-the-counter, and herbal products, especially blood thinners (warfarin, aspirin), diuretics, lithium, methotrexate, and ACE inhibitors. · If you are pregnant, planning to become pregnant, or breastfeeding, discuss the risks with your healthcare provider. |
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