NABUMETONE (RELAFEN)
Nabumetone is a non-acid non-steroidal anti-inflammatory with non selective prostaglandin inhibitory analgesic and antipyretic (fever reducer) effects. It is a pro-drug that is, it is metabolized or made active in the liver to its pharmaceutical form. Since 80% of Nabumetone is found in the urine it is well absorbed from the digestive tract.
It may be taken with either food or antacids (of the aluminum type) without affecting absorption and providing additional protection from gastric upset. The drug must be carefully monitored in patients with renal insufficiency since its extensive protein-binding property renders it non dialyzable though no reduction in dosage is usually necessary due to its extensive hepatic (liver) metabolism. In contrast to aspirin, Nabumetone produced no evidence of fecal blood loss, and less endoscopically detected lesions of the intestines
INDICATIONS
Nabumetone is indicted for the treatment of pain associated with osteoarthritis (DJD, OA) , rheumatoid arthritis (RA) , and should be avoided in patients with any history of allergic reactions to aspirin or any other NSAIDs, and patients with severe asthma or post coronary artery bypass graft surgery (CABG). Dosages of 500mg to 750mg twice daily are usually prescribed or may be given as one daily dose for enhanced compliance, and may be taken with corticosteroids and gold salt medications. Doses up to 2000mg per day may be given, with the lowest dosages for chronic treatment.
SIDE EFFECTS
Patients on Nabumetone may experience fluid retention and lower extremity edema and my complicate the edema of congestive heart failure. Photosensitivity reactions may occur depending upon patient individual tanning properties and should be careful regarding excessive sun exposure when taking the medication. Patients taking this and other NSAIDs on a long term basis should be monitored with hepatic enzymes and other laboratory tests.
Drug interactions are based upon its protein-binding affinity. Significant care must be taken if coadministered to patient on warfarin. Nabumetone should be avoided in the third trimester of pregnancy and by nursing mothers due to the prostaglandin inhibition effects on the human fetal cardiovascular system which my cause closure of the patent ducts arteriosus. The drug is not indicated for pediatric patients and is well tolerated by senior citizens.
When properly used the side effects are less than 1-3% of the population and affect the:
Gastrointestinal tract- such as anorexia, jaundice, ulcers, dysphasia, increased appetite
Central Nervous System- agitation, anxiety, confusion, depression, malaise, tremor vertigo
Dermatological- photosensitivity, bullae, TEN (toxic epidermal necrolysis), SJS (Stevens - Johnson syndrome),
Cardiovascular system-MI, thrombophlebitis, angina, arrthymia, hypertension, syncope, palpitations,
Metabolic- weight gain, hyperglycemia, hyopkalemia (reduced K+ potassium) weight loss
Respiratory- asthma, cough, dyspnea, pneumonitis
General- taste disorders, abnormal vision, tinnitus (ringing in the ears)
Over dosages usually manifest as lethargy, drowsiness, nausea , vomiting, epigastric pain and all are treated by supportive measures, More serious problems may include significant gastrointestinal bleeding, respiratory depression, renal failure, coma Instances of over dosages up to 25 grams have found no long term squealae upon treatment with emesis, gastric lavage, and IV supportive measures with H2 (selective histamine GI receptors)
REFERENCES
PDR, Physicians Desk Reference vol #59 2005
MPR, Monthly Prescribing Reference, July 2011
Drugs. Com, ‘Nabumetone.
In my daily practice, I have found Nabumetone to be a well tolerated anti-inflammatory analgesic for my adult foot ankle sprain/strains , fascitis, tendonitis patients. The advantage of a one day dose enhances compliance and favorable outcome.
See our other pain medication discussions.
