Acetaminophen And Codeine and Uric Acid Measurement: Interaction Details
AI-assisted, pharmacist-reviewed · AI content regenerated Jul 11, 2026 · Source data updated Jul 1, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Acetaminophen And Codeine
Uric Acid Measurement
No brand names on record
How we grade severity & evidence
Severity levels
- Contraindicated: These should generally not be used together.
- Major: Potentially serious — often needs a change or close monitoring.
- Moderate: Can be significant — usually manageable with monitoring.
- Minor: Usually limited clinical impact.
Evidence grades
- Established: Well documented — supported by controlled studies or strong clinical data.
- Probable: Good supporting evidence, though not definitively proven.
- Suspected: Some evidence suggests this interaction, but it is not well established.
- Possible: Limited or conflicting evidence; the interaction may occur.
- Theoretical: Predicted from the drugs' pharmacology; not yet confirmed in people.
Ratings come from the documented interaction literature and are reviewed by a pharmacist. They describe the documented risk of the combination, not what will necessarily happen to you — your dose, timing, and health picture all matter.
This isn't a case of two medicines causing harm together. Instead, the acetaminophen in your acetaminophen and codeine pills can throw off one specific lab test, the one that measures uric acid in your blood.
When an older method (called the phosphotungstic acid method) is used, acetaminophen can make your uric acid number look higher than it truly is. Your body's real uric acid level hasn't changed, the test is just being fooled. The good news: your care team can simply use a different, more accurate test. If you're due for a uric acid check, just mention that you take acetaminophen and codeine.
Nature: Analytical (in vitro) interference, not a pharmacologic interaction. Therapeutic-dose acetaminophen (the non-opioid component of acetaminophen/codeine) causes falsely elevated serum uric acid when measured by the phosphotungstate reduction method.
- Direction: Spuriously increased result; true uric acid unchanged.
- Mechanism: Acetaminophen reduces phosphotungstic acid, mimicking urate.
- Onset: Rapid; Evidence: probable.
- Management: Use the enzymatic uricase assay in patients known or suspected to have taken acetaminophen. Codeine is not implicated.
What happens
Falsely increased serum uric acid levels
Interaction Deep Dive
In individuals who have received therapeutic doses of acetaminophen, serum uric acid measurements obtained through the phosphotungstic acid chemical method may be falsely high. For patients suspected of acetaminophen use, the enzymatic uricase method should be considered as an alternative for measuring serum uric acid concentrations1.
Why it happens (mechanism)
Assay interference with the phosphotungstate reduction method
How to manage this interaction
This is a lab-testing issue, not a reason to change your medicine.
- Keep taking your acetaminophen and codeine as prescribed.
- Tell the lab or your care team that you take acetaminophen before a uric acid blood test.
- Your team can order the more accurate enzymatic (uricase) method, which is not affected by acetaminophen.
- If you already had a uric acid result that seems unexpectedly high, ask your pharmacist or doctor whether it should be rechecked with the enzymatic test.
Handled this way, your results will reflect your true uric acid level.
Management is individual — confirm any change with your pharmacist or prescriber.
Literature reports
1 report — tap to read
a) Acetaminophen, at therapeutic doses, interferes with the serum uric acid assay. Serum uric acid may be measured using either the chemical phosphotungstic acid method or the enzymatic uricase method. Several substances are recognized to interfere with the chemical phosphotungstic acid method, such as ascorbic acid, aspirin, levodopa, and methyldopa. Acetaminophen has likewise been shown to interfere with this assay at therapeutic doses. Two subjects received 2 g acetaminophen and one received 1 g acetaminophen. Serum uric acid was drawn from them prior to the dose and subsequently at intervals of 0.5, 1, 2, and 5 hours. Uric acid values were determined using both the chemical phosphotungstic acid method and the enzymatic uricase method. A 1 g dose of acetaminophen increased apparent uric acid levels by 2 mg/dL. A 2 g dose of acetaminophen increased apparent uric acid levels by 3 to 4 mg/dL. All three subjects had uric acid levels exceeding their basal values for at least two hours following the final acetaminophen administration 1.
Common questions
Can I take Acetaminophen And Codeine and Uric Acid Measurement together?
Acetaminophen can make one older uric acid blood test read falsely high, but your true level is unchanged. Just tell your care team you take it so they can use the accurate enzymatic (uricase) test. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Acetaminophen And Codeine and Uric Acid Measurement interaction?
It is rated moderate. Can be significant — usually manageable with monitoring.
How quickly could this interaction happen?
The documented onset is "rapid". Effects can appear quickly, often within about 24 hours of combining the drugs.
How is the Acetaminophen And Codeine and Uric Acid Measurement interaction managed?
This is a lab-testing issue, not a reason to change your medicine. Keep taking your acetaminophen and codeine as prescribed. Tell the lab or your care team that you take acetaminophen before a uric acid blood test. Your team can order the more accurate enzymatic (uricase) method, which is not affected by acetaminophen. If you already had a uric acid result that seems unexpectedly high, ask your ph… Management is individual — always follow your own care team's guidance.
How strong is the evidence for this interaction?
The evidence is graded "probable". Good supporting evidence, though not definitively proven.
Questions for your pharmacist
- Does my dose of Acetaminophen And Codeine or Uric Acid Measurement need adjusting while I take them together?
- What symptoms should prompt me to call you or my prescriber right away?
- Does the timing of my doses matter for this combination?
- Is there anything you'd monitor while I'm on both?
References (1)
- Wilding P & Heath DA: Effect of paracetamol on uric acid determination. Ann Clin Biochem 1975; 12(4):142-144. PubMed
Keep reading about Acetaminophen And Codeine
Keep reading about Uric Acid Measurement
Check another combination
Our instant two-drug interaction checker is almost here.
Still have questions about this combination?
Every question gets a real answer from a licensed pharmacist — free, and usually within a day.
Ask the pharmacist