Based on NIH | I heard you shouldn’t take naproxen if you eat fish at night—is there any evidence of an interaction?

There is no evidence of a harmful interaction between naproxen and eating fish at night

• In general, naproxen (an NSAID) can be taken with or without food, and its overall absorption is not significantly altered by food. ^[1] Studies of naproxen controlled‑release tablets show that food may slightly change peak levels but does not meaningfully change total exposure or effectiveness. ^{[2] [3]} Over-the-counter labels for naproxen advise taking it with food or milk if stomach upset occurs, but they do not list fish or seafood as a specific interaction. ^{[4] [5]}

What we know about food and naproxen

• Naproxen is absorbed well by mouth and is only minimally affected by food overall. ^[1] With controlled‑release formulations, food can lower or shift peak concentrations without changing the total amount absorbed, which generally doesn’t change clinical effect. ^{[2] [3]} Consumer directions commonly suggest taking naproxen with food or milk to reduce stomach irritation this is about comfort, not a safety interaction with specific foods. ^{[4] [5]}

Where the “fish” concern may come from

• Some medications, like isoniazid (a tuberculosis drug), can interact with foods high in histamine (for example, certain tuna or mackerel associated with “scombroid” poisoning) or tyramine; that warning does not apply to naproxen. ^{[6] [7]} Fish that is improperly stored can cause histamine poisoning (scombroid), which looks like an allergic reaction regardless of what medicines are taken, because the histamine is heat‑stable and not destroyed by cooking. ^[8] This is a food safety issue, not a naproxen interaction. ^[8]

Practical guidance for taking naproxen safely

• Take naproxen at the lowest effective dose for the shortest time needed and consider taking it with food or milk if you tend to get stomach upset. ^{[4] [5]}
• Be mindful of naproxen’s known risks: it can increase the risk of stomach bleeding, especially with alcohol or when combined with other NSAIDs, and it carries cardiovascular cautions; these are standard NSAID warnings and are unrelated to fish intake. ^{[9] [10]}
• If you develop symptoms after eating fish such as flushing, hives, headache, or diarrhea within an hour consider scombroid poisoning as a possible cause; this is due to histamine in spoiled fish and is not caused by naproxen. ^[8]

Bottom line

• There is no documented interaction between naproxen and eating fish at night. ^{[1] [2] [4]} If you tolerate naproxen, you may take it with a fish meal as you would with any other meal, preferably with food if you are prone to stomach upset. ^{[4] [5]}

Would you like help reviewing your naproxen dose and any other medicines you’re taking to check for known interactions?