Aspirin and Dipyrone: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Jul 11, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Dipyrone
No brand names on recordAspirin
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.
What happens
Reduced efficacy of aspirin, an increased risk of bleeding, and decreased renal function
Interaction Deep Dive
Concurrent use of aspirin with dipyrone (an NSAID) is generally not recommended due to an increased risk of bleeding and may also lead to decreased renal function1. Use dipyrone with caution in patients taking aspirin for secondary cardiovascular prevention. Mortality and major adverse cardiac and cerebrovascular events were significantly increased with aspirin plus dipyrone therapy versus aspirin alone as secondary prophylaxis in patients with a cardiovascular event in a large cohort study 2. The antiplatelet efficacy of low-dose aspirin may be reduced when used concomitantly with dipyrone. Residual platelet reactivity (aggregation greater than 0%) and high on-treatment reactivity (aggregation greater than 20%) occurred in significantly more patients with stroke or TIA receiving concomitant low-dose aspirin and dipyrone versus aspirin alone 4. Significant differences were also observed for platelet aggregation and thromboxane formation in a study in patients with stable cardiovascular, cerebrovascular, or peripheral arterial disease who received low-dose aspirin with at least 5 days of dipyrone 3. Neurological recovery at 3 months was also significantly reduced in the stroke/TIA patients with concomitant use 4.
Why it happens (mechanism)
Attenuated antiplatelet effect of aspirin; additive anticoagulant effects
Literature reports
3 reports — tap to read
a) A retrospective propensity-score adjusted cohort study compared mortality events in patients with a cardiovascular event who received secondary prophylaxis with aspirin only (n=26,200) or aspirin plus dipyrone (n=5946) and followed them for 36 months. Compared with aspirin alone, aspirin plus dipyrone therapy significantly increased all cause mortality (24.4% vs 15.6%; HR, 1.66; 95% CI, 1.56 to 1.76; number needed to harm [NNH], 11), major adverse cardiac and cerebrovascular events (mortality, stroke, or myocardial infarction; 33.9% vs 24.9%; HR, 1.45; 95% CI, 1.38 to 1.53; NNH, 11.15), myocardial infarction (5.9% vs 5.2%; HR, 1.18; 95% CI, 1.05 to 1.32; NNH, 140), and stroke/TIA (8.5% vs 7.3%; HR, 1.22; 95% CI, 1.11 to 1.35; NNH, 82); there was no significant difference in bleeding events (0.6% vs 0.4%). The mean age was 72 years in the aspirin only group and 70 years in the aspirin plus dipyrone group; and 56.4% and 56.7% were men. The aspirin dosage was 75 to 100 mg/day, and the mean dipyrone dosage was 2.06 mg/day 2.
b) Complete inhibition of arachidonic acid-induced platelet aggregation was achieved in significantly fewer patients with stable cardiovascular, cerebrovascular, or peripheral arterial disease who were receiving long-term low-dose aspirin (100 mg/day) with dipyrone 1500 to 4000 mg/day for at least 5 days (n=27) compared with patients who received aspirin 100 mg/day without dipyrone (n=10) in a case-control study (22% vs 90%). Thromboxane formation was significantly greater in the aspirin plus dipyrone group versus aspirin alone (387 vs 7 nanograms/mL) 3.
c) Residual platelet reactivity (aggregation greater than 0%) occurred in a significantly greater proportion of patients who received concomitant dipyrone (for 3 days or longer) plus low-dose aspirin (100 mg/day) compared with low-dose aspirin alone (67% vs 10%) in a cohort study in patients post acute stroke or transient ischemic attack (N=41). High on-treatment platelet reactivity (maximum aggregation greater than 20%) occurred in 0% with aspirin alone versus 33% with dipyrone plus aspirin, a significant difference. Excellent neurological recovery, defined as a modified Rankin scale of less than 2 at 3 months after stroke onset, was observed in a significantly greater proportion of patients who received aspirin alone versus those with the concomitant therapy (80% vs 48%) 4.
Common questions
Can I take Aspirin and Dipyrone together?
Reduced efficacy of aspirin, an increased risk of bleeding, and decreased renal function Always confirm with your pharmacist or prescriber before making any change.
How serious is the Aspirin and Dipyrone interaction?
It is rated major. Potentially serious — often needs a change or close monitoring.
How quickly could this interaction happen?
The documented onset is "unspecified". The timing of this interaction is not well characterized.
How strong is the evidence for this interaction?
The evidence is graded "established". Well documented — supported by controlled studies or strong clinical data.
From our Q&A
Real reader questions about these medications, each personally answered by our pharmacist:
Questions for your pharmacist
- Does my dose of Aspirin or Dipyrone 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 a safer alternative to one of these medications for me?
References (4)
- Product Information: CARISOPRODOL, ASPIRIN, CODEINE PHOSPHATE oral tablets, carisoprodol, aspirin, codeine phosphate oral tablets. Ingenus Pharmaceuticals LLC (per DailyMed), Orlando, FL, 2021. DailyMed
- Polzin A, Dannenberg L, Helten C, et al: Excess mortality in aspirin and Dipyrone (metamizole) co-medicated in patients with cardiovascular disease: a nationwide study. J Am Heart Assoc 2021; 10(22):e022299-.
- Schmitz A, Romann L, Kienbaum P, et al: Dipyrone (metamizole) markedly interferes with platelet inhibition by aspirin in patients with acute and chronic pain: a case-control study. Eur J Anaesthesiol 2017; 34(5):288-296. DOI
- Dannenberg L, Erschoff V, Bonner F, et al: Dipyrone comedication in aspirin treated stroke patients impairs outcome. Vascul Pharmacol 2016; 87:66-69. PubMed
Keep reading about Dipyrone
Keep reading about Aspirin
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