Do blueberries increase naproxen side effects?

Based on human data and official safety information, typical dietary intake of blueberries does not appear to increase the risk of naproxen side effects in a clinically meaningful way. Blueberry juice has been studied for potential drug‑metabolism interactions and showed no significant effect on the clearance of a closely related NSAID (flurbiprofen, a CYP2C9 substrate), suggesting a low likelihood of relevant interaction with NSAIDs like naproxen at usual food amounts. ^[1] NSAID safety guidance emphasizes interactions with certain medications (e.g., anticoagulants, aspirin) rather than common foods such as blueberries. ^[2]

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What we know about blueberries and NSAID metabolism

• Blueberries contain anthocyanins and other polyphenols that can inhibit drug‑metabolizing enzymes in test tubes, which raised theoretical concerns. However, when tested in people, blueberry juice did not significantly change exposure to flurbiprofen (CYP2C9 substrate) and had no clinically meaningful effect on buspirone (CYP3A substrate). ^[1]
• Anthocyanins are absorbed and extensively metabolized, with low plasma levels and rapid clearance, which further reduces the chance of strong, sustained interaction with drug metabolism at dietary doses. ^[3]

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Naproxen’s main risks and proven interactions

Naproxen is a nonsteroidal anti-inflammatory drug (NSAID). Its most important side effects relate to the stomach and intestines (ulcers and bleeding), kidneys, blood pressure, and the heart, and these risks increase with dose and duration. These adverse effects are well documented for NSAIDs regardless of foods, and caution is advised especially in older adults and those with prior ulcers. ^{[4] [5]}

• Platelet function and bleeding: NSAIDs can impair platelet function and increase the severity of upper gastrointestinal bleeding; this risk is intrinsic to the drug. ^[6]
• Additive bleeding risk with certain drugs: Combining NSAIDs with anticoagulants or antiplatelet drugs (like warfarin or aspirin) markedly increases bleeding risk; this is a well‑recognized and clinically important interaction. ^{[7] [8]}
• General interaction advice: Official NSAID medication guides advise discussing all new medicines, vitamins, and herbal supplements with a clinician due to potential interactions, but they do not specifically flag blueberries or typical foods as hazards. ^{[2] [9]}

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Evidence summary table

Topic	Key finding	Human clinical relevance
Blueberry juice and CYP2C9/CYP3A substrates	No significant change in flurbiprofen AUC; small, non‑significant change in buspirone	Suggests low likelihood of blueberry‑NSAID interaction at usual intake
Anthocyanin pharmacokinetics	Low plasma levels; rapid clearance; extensive metabolism	Reduces potential for sustained drug‑enzyme interaction
NSAID bleeding risk	NSAIDs impair platelets; increase GI bleed severity	Core mechanism of NSAID harm, independent of typical foods
NSAIDs with anticoagulants/antiplatelets	Synergistic GI bleeding risk	Clinically major interaction to avoid or closely manage
NSAID safety guidance about foods	Emphasizes medicines/supplements, not blueberries	No official warning about blueberries with NSAIDs

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Practical guidance

• Normal portions of blueberries are unlikely to increase naproxen side effects. Available human data do not show a clinically important interaction between blueberry juice and a comparable NSAID substrate, and safety materials focus on drug–drug interactions, not common fruits. ^{[1] [2]}
• Focus on proven risks: If you take naproxen, the bigger risks come from high doses, prolonged use, a history of ulcers, alcohol use, and combining with aspirin, anticoagulants (e.g., warfarin), corticosteroids, or SSRIs, all of which can raise bleeding risk. ^{[4] [7] [8]}
• Watch for warning signs: Black or tarry stools, vomiting blood, persistent stomach pain, new or worsening heartburn, swelling, sudden weight gain, or shortness of breath should prompt medical attention. These are established NSAID adverse effects and warrant caution irrespective of diet. ^{[2] [9]}

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When to be extra cautious

• If you are on anticoagulants or antiplatelets: The combination with any NSAID significantly elevates bleeding risk; consult your clinician before using naproxen. ^{[7] [8]}
• If you have a history of ulcers or GI bleeding: Consider protective strategies (e.g., proton pump inhibitors) or alternative pain options under medical guidance. This is far more impactful than adjusting blueberry intake. ^[4]

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Bottom line

The best available human evidence suggests that blueberries, at normal dietary amounts, do not meaningfully increase naproxen side effects. The primary concerns with naproxen relate to dose, duration, your medical history, and concurrent medications (especially blood thinners and aspirin), not typical fruit consumption. ^{[1] [2] [7] [8]}