ACHES-N-PAIN
Clinical safety rating: caution
Comprehensive clinical and safety monograph for ACHES-N-PAIN (ACHES-N-PAIN).
Non-selective inhibition of cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2), leading to decreased synthesis of prostaglandins.
| Metabolism | Primarily hepatic via CYP2C9; undergoes glucuronidation and sulfation. |
| Excretion | Renal excretion of unchanged drug and metabolites (primarily glucuronide conjugates) accounts for ~85% of elimination; fecal excretion accounts for ~15%. Biliary excretion is minor. |
| Half-life | Terminal elimination half-life is 2–4 hours in adults with normal renal function. In patients with hepatic impairment or severe renal impairment (CrCl <30 mL/min), half-life may be prolonged up to 6–8 hours, necessitating dose adjustment. |
| Protein binding | Approximately 90–95% bound to plasma proteins, primarily albumin, with minor binding to alpha-1-acid glycoprotein. |
| Volume of Distribution | 0.8–1.2 L/kg, indicating distribution into total body water and some tissue binding. Higher Vd in obese patients (up to 1.5 L/kg) due to increased adipose tissue. |
| Bioavailability | Oral: 80–90% (first-pass metabolism ~10–20%). Rectal: 70–80% (variable due to absorption site). Intramuscular: 90–100% (complete absorption). Intravenous: 100%. |
| Onset of Action | Oral: 30–60 minutes (analgesic effect). Intramuscular: 15–30 minutes. Intravenous: 5–10 minutes. Rectal: 30–90 minutes due to variable absorption. |
| Duration of Action | Oral: 4–6 hours. Intramuscular: 4–6 hours. Intravenous: 4–6 hours. Rectal: 4–6 hours. Duration may be shortened with chronic use due to tolerance or enzyme induction. |
650 mg orally every 4-6 hours as needed, not to exceed 4000 mg per day.
| Dosage form | TABLET |
| Renal impairment | eGFR 30-60 mL/min: 650 mg every 6 hours; eGFR <30 mL/min: 650 mg every 8 hours; avoid if eGFR <15 mL/min. |
| Liver impairment | Child-Pugh Class A: no adjustment; Class B: 650 mg every 8 hours; Class C: avoid use. |
| Pediatric use | 10-15 mg/kg orally every 4-6 hours, not to exceed 75 mg/kg/day or 4000 mg/day. |
| Geriatric use | Reduce dose by 50% if multiple comorbidities or frail; maximum 3000 mg/day; monitor for toxicity. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for ACHES-N-PAIN (ACHES-N-PAIN).
| Breastfeeding | Ibuprofen is excreted into breast milk in low concentrations (M/P ratio approximately 0.6). Short-term use is considered compatible with breastfeeding. Monitor infant for gastrointestinal disturbance or rash. |
| Teratogenic Risk | FDA Pregnancy Category C. First trimester: Increased risk of neural tube defects and cardiovascular malformations based on observational studies of NSAIDs. Second trimester: Possible oligohydramnios and fetal renal impairment with prolonged use. Third trimester: High risk of premature closure of ductus arteriosus, fetal nephrotoxicity, and periventricular hemorrhage. Avoid in pregnancy unless clearly needed. |
■ FDA Black Box Warning
Nonsteroidal anti-inflammatory drugs (NSAIDs) cause an increased risk of serious cardiovascular thrombotic events, including myocardial infarction and stroke, which can be fatal. This risk may increase with duration of use. Patients with cardiovascular disease or risk factors for cardiovascular disease may be at greater risk. ACHES-N-PAIN is contraindicated for the treatment of peri-operative pain in the setting of coronary artery bypass graft (CABG) surgery.
| Serious Effects |
History of allergic reaction to aspirin or other NSAIDs, active peptic ulcer, significant renal impairment (CrCl <30 mL/min), severe hepatic impairment, peri-operative pain in CABG surgery, third trimester of pregnancy.
| Precautions | Risk of serious gastrointestinal adverse events including bleeding, ulceration, and perforation. Use with caution in patients with a history of peptic ulcer disease or GI bleeding. May cause hypertension, fluid retention, and exacerbate renal impairment. Avoid use in late pregnancy (third trimester). |
| Food/Dietary | Avoid alcohol; may increase acetaminophen hepatotoxicity and ibuprofen GI bleeding risk. Grapefruit juice may reduce ibuprofen absorption; separate administration by 4 hours. |
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| Fetal Monitoring | Monitor for maternal gastrointestinal bleeding, hypertension, renal function, and signs of bleeding tendency. In third trimester, ultrasonography for amniotic fluid index and ductus arteriosus flow if used beyond 48 hours. |
| Fertility Effects | Reversible inhibition of ovulation via interference with prostaglandin synthesis. Use may be associated with delayed conception. Effect resolves upon discontinuation. |
| Clinical Pearls | ACHES-N-PAIN is a combination analgesic containing acetaminophen, ibuprofen, and caffeine. Avoid concurrent use with other acetaminophen-containing products due to hepatotoxicity risk. Ibuprofen dose should not exceed 3200 mg/day; renal function monitoring required in elderly. Caffeine may cause tachycardia or insomnia. |
| Patient Advice | Do not take more than the recommended dose; exceeding acetaminophen 4000 mg/day can cause liver damage. · Avoid alcohol while taking this medication to prevent hepatotoxicity. · Take with food or milk to reduce gastrointestinal irritation from ibuprofen. · Do not use if you have a history of peptic ulcer disease, severe renal impairment, or hypersensitivity to NSAIDs. · Discontinue and seek medical attention if signs of allergic reaction (rash, swelling, difficulty breathing) or GI bleeding (black stools, vomiting blood) occur. |