According to Columbia University, dangers that come with a prolonged use of Aleve or any form of Naproxen include heart attacks, strokes, kidney problems and gastrointestinal bleeding. Dangers are minimized if the user takes the medicine properly as directed.
Taking Aleve for long periods of time at high doses has the potential to cause gastrointestinal bleeding, which develops more quickly in those who also drink alcohol, according to Columbia University. Kidney problems include kidney cancer, failure, renal papillary necrosis and renal toxicity. These problems are more likely to develop in people who have diabetes or hypertension. Being over 60 years old also increases these risks.
Columbia University experts warn that 1,500 milligrams is the maximum dose to in one day, and for no longer than 10 days for pain and three for fever relief.