Since the last Medical Letter article on glucosamine for osteoarthritis (vol.39, page 91, September 26, 1997), more data have become available. Glucosamine is available in US pharmacies and health food stores as sulfate, hydrochloride or n-acetyl salt.

Drugs for gout are used to reduce the pain and inflammation of acute flares, decrease the frequency of exacerbations, and lower serum urate levels to prevent recurrent flares, development of tophi, and joint damage.

The FDA has approved Vivlodex (Iroko), a low-dose formulation of the nonsteroidal anti-inflammatory drug meloxicam (Mobic, and generics), for management of osteoarthritis pain. According to the manufacturer, the new formulation aligns with stronger FDA warnings about the cardiovascular risks of NSAIDs and the recommendation to use the lowest possible doses of these drugs.

The results of a recently published study suggest that taking the oral direct thrombin inhibitor dabigatran etexilate (Pradaxa) with either simvastatin (Zocor, and others) or lovastatin (Altoprev, and others) increases the risk of major hemorrhage.

View the Inhibitors and Inducers of CYP Enzymes, P-Glycoprotein, and Other Transporters tables

Changes caused by one drug in the absorption, distribution, metabolism or excretion of another may lead to a pharmacokinetic adverse drug interaction (DN Juurlink et al, JAMA 2003; 289:1652). Additive drug interactions, such as vasodilation caused by both sildenafil (Viagra) and nitrates, can also have adverse effects.

Until the recent introduction of febuxostat (Uloric), no new drugs had been marketed for treatment of gout in the past 40 years. Colchicine, which has been available for decades as an unapproved drug, has now been approved by the FDA (Colcrys) for treatment and prophylaxis of gout flares. It was approved earlier only in combination with probenecid (Colbenemid, and others). The goals of gout treatment are three-fold: treating acute disease, preventing flares and reducing uric acid stores.

View the Comparison Table: Some Nonopioid Analgesics for Pain

Psoriatic arthritis is a chronic inflammatory arthropathy associated with psoriasis. A recent review found that about 20% of patients with psoriasis have psoriatic arthritis. Updated guidelines for treatment of psoriatic arthritis have recently been published.

A new CDC guideline for prescribing opioids for pain recently became available. Nonopioid drugs for pain were reviewed in a previous issue.