Acetaminophen Extended Release (Tylenol 8HR)
Bilayer 650 mg acetaminophen tablet containing 325 mg immediate-release and 325 mg extended-release drug for up to 8 hours of relief. Do not crush, chew, split, or dissolve the tablet.
Projected serum levels — 1.3k mg, as needed (shown daily)
Maintenance schedule: 1.3k mg as needed (shown daily) (oral).
Modeled steady state after ~1 days: peak ≈ 550 mg, trough ≈ 2.0 mg body load. Population-based estimate over 15 days for a 1.3k mg dose at a 70 kg reference body mass — the interactive app scales curves to your doses, timing, and body mass.
Key facts
- Category
- Analgesic
- Route modeled
- Oral
- Model confidence
- predicted
- Half-life
- 2.3 h
- Common dose
- 1.3k mg
- Suggested maximum
- 3.9k mg/day
- Reference dose range
- 650–3.9k mg (single dose)
- Suggested cadence
- as needed (shown daily)
Research behind this entry
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Efficacy and safety of paracetamol for spinal pain and osteoarthritis: systematic review and meta-analysis of randomised placebo controlled trials
Meta-analysis found paracetamol was ineffective for low back pain and provided only small, clinically insignificant benefits for osteoarthritis pain and disability.
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Acetaminophen-induced hepatotoxicity: a comprehensive update
Review establishing acetaminophen overdose as the leading cause of acute liver failure in the US, detailing the NAPQI toxicity mechanism and NAC treatment.
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Paracetamol: not as safe as we thought? A systematic review of observational studies
Systematic review found dose-response relationship between paracetamol use and adverse events including increased cardiovascular, GI, and renal risks at higher doses.
3 published studies referenced in the app, each with a plain-language summary.