Nabumetone is used to relieve pain, tenderness, swelling, and stiffness caused by osteoarthritis (arthritis caused by a breakdown of the lining of the joints) and rheumatoid arthritis (arthritis caused by swelling of the lining of the joints). Pain Home Relafen and Weight Gain While weight gain is a rare Relafen side effect (occurring in less than 1 percent of people who take the drug), it could signify congestive heart failure in some people taking the drug. Summary. Weight increased is found among people who take Nabumetone, especially for people who are female, 60+ old , have been taking the drug for 5 - 10 years, also take medication Lyrica, and have Fibromyalgia. Nabumetone may also cause stomach or intestinal bleeding, which can be fatal. These conditions can occur without warning while you are using nabumetone, especially in older adults. These conditions can occur without warning while you are using nabumetone, especially in older adults. The information reflected here is dependent upon the correct functioning of our algorithm. From time-to-time, our system might experience bugs or glitches that affect the accuracy or correct application of mathematical algorithms. Of the 1,677 patients who received RELAFEN (nabumetone) during US clinical trials, 1,524 were treated for at least 1 month, 1,327 for at least 3 months, 929 for at least a year, and 750 for at least 2 years. More than 300 patients have been treated for 5 years or longer. Yes, There is rapid weight gain with Nabumetone. Relafen, Relifex, and Gambaran are the brand name of Nabumetone. It is a nonsteroidal anti-inflammatory drug (NSAID) with anti-inflammatory, antipyretic and analgesic activities. Side Effects. Drug information provided by: IBM Micromedex. Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention. Can Relafen cause Weight Gain? Complete analysis from patient reviews and trusted online health resources, including first-hand experiences. Complete analysis from patient reviews and trusted online health resources, including first-hand experiences. Doctors give unbiased, trusted information on whether Nabumetone can cause or treat Weight Gain: Dr. Fowler on nabumetone and weight gain: Most people who take zoloft don't gain much weight, if any. 5 in a year is fairly typical. Some people do gain substantial amounts though. The only antidepressant not associated with weight gain is.