Never take anything that written on the medications with a grain of salt. Disregard everything that you have read online. The medicine instructions are your single source of truth

Is the salt supposed to offset hyponatremia or something?

Both ibuprofen and naproxen sodium are NSAIDs and are bad for your kidneys especially in long term. I had kidney failure due to what was eventually diagnosed as an autoimmune disease but they first thing the ER doctor will ask is if you have been taking NSAIDs. My nephrologists told be its still safe to take acetaminophen at the proper dose.

None of us are your doctors but Naproxen has well-known gastric issues up to ulcers and stomach bleeding which is why it's advised to be taken with food and why it's also often prescribed with a PPI or H2 Antagonist. Cox-2 selectives such as Celecoxib greatly reduce this risk but seem to be associated with some small cardiovascular risk (admittedly this is a feature of all NSAIDs though less so in Naproxen apparently).

Some believe naproxen sodium is worse for you because it lasts longer. Longer duration for reduced mucous membrane coverage in your stomach and intestine. Longer duration for reduced blood flow to your kidneys.

I would definitely have a chat with a doctor about it.

Looking at the Wikipedia article, it seems naproxen is a NSAID like ibuprofen and can cause all the same gastrointestinal issues.

Naproxen sodium has much higher risk of GI damage especially with long term use.

wait, how are you getting naproxen?

Whenever its prescribed here, its paired with some sort of intestine protection medicine to stop it burning holes in your stomach/intenstines

Ibuprofen is much safer, so long as you eat with it.

Paracetamol is also safer, so long as you don't OD.

BUT! so long as you stay below 4 grams a day, you'll be safe. (yes yes, in some situations you can take double, but unless you are under supervision, thats asking for liver pain.)

I had to use naproxen for some time as most effective way to control inflammation. Actually the only way, ibuprofen had some effect only in horse dozes. After visiting doctor, analyses, checking available sources was able to eliminate the reason of inflammation. Apparently it was a well known problem/solution. So far so good. Not sure about the long lasting effects of naproxen use.

All the over the counter NSAIDs have a similar safety profile.