Comparison of the efficacy and safety of naproxen CR and nabumetone in the treatment of patients with osteoarthritis of the knee

Zaltoprofen, a noninferior alternative to diclofenac for the treatment of primary knee osteoarthritis -- a comparative evaluation of efficacy and safety in a 4-week, multicentric, randomized, double-blind, double-dummy trial

OBJECTIVE

To demonstrate the clinical noninferiority of the analgesic effect of zaltoprofen (80 mg t.i.d.) compared with diclofenac (50 mg t.i.d.) in active knee osteoarthritis patients.

METHOD

In this multicentric, double-blind, double-dummy, randomized, parallel-group, comparative study, 213 patients of either sex, aged 40 - 65 years having radiological and clinically confirmed primary knee osteoarthritis were randomized either to zaltoprofen (n = 105) or diclofenac (n = 108) and were followed-up at weeks 1, 2, 3 and 4. The treatment period was preceded by a washout period of 1 week.

RESULTS

Patients in both the zaltoprofen and diclofenac groups exhibited significant improvement (p < 0.001) in pain intensity, functional status and pain relief at each visit from baseline with no statistically significant difference between the two treatment groups. There was no statistically significant difference between the treatment groups for global assessment rating done by the patient and investigator at the end of therapy (p > 0.05) and the proportion of patients who consumed ranitidine (p = 0.135) and paracetamol (p = 0.086) tablets during the treatment period on both the treatment arms. Both the study medications were well tolerated with no incidence of serious adverse events.

CONCLUSIONS

This study demonstrated that efficacy and safety of zaltoprofen is clinically noninferior to that of diclofenac.

Nonsteroidal anti-inflammatory drugs and hepatic toxicity: a systematic review of randomized controlled trials in arthritis patients

BACKGROUND & AIMS

Nonsteroidal anti-inflammatory drugs (NSAIDs) might cause hepatic side effects, but the frequency of these laboratory and clinical side effects is uncertain.

METHODS

Searches of bibliographic databases MEDLINE and EMBASE and of public archives of the Food and Drug Administration were conducted to identify randomized controlled trials of diclofenac, naproxen, ibuprofen, celecoxib, rofecoxib, valdecoxib, or meloxicam in adults with osteoarthritis or rheumatoid arthritis that provided information on aminotransferase elevations >3 x upper limit of normal, liver-related discontinuations, hepatic serious adverse events, liver-related hospitalizations, or liver-related deaths. The proportion of patients with each of the hepatic toxicity outcomes was calculated separately by using sample size weighted pooling for each NSAID.

RESULTS

Sixty-seven articles from the bibliographic database and 65 studies from the Food and Drug Administration archives met inclusion criteria. Diclofenac (3.55%; 95% confidence interval [CI], 3.12%-4.03%) and rofecoxib (1.80%; 95% CI, 1.52%-2.13%) had higher rates of aminotransferase >3 x upper limit of normal than placebo (0.29; 95% CI, 0.17-0.51) and the other NSAIDs (all < or = 0.43%). The 95% CIs for liver-related discontinuations of all NSAIDs except diclofenac (2.17%; 95% CI, 1.78%-2.64%) overlapped with placebo. Only 1 liver-related hospitalization (among 37,671 patients) and 1 liver-related death (among 51,942 patients) occurred, with naproxen.

CONCLUSIONS

Diclofenac and rofecoxib had higher rates of aminotransferase elevations than placebo and other NSAIDs studied. No NSAID studied had increased rates of liver-related serious adverse events, hospitalizations, or deaths.

Nabumetone: therapeutic use and safety profile in the management of osteoarthritis and rheumatoid arthritis

Nabumetone is a nonsteroidal anti-inflammatory prodrug, which exerts its pharmacological effects via the metabolite 6-methoxy-2-naphthylacetic acid (6-MNA). Nabumetone itself is non-acidic and, following absorption, it undergoes extensive first-pass metabolism to form the main circulating active metabolite (6-MNA) which is a much more potent inhibitor of preferentially cyclo-oxygenase (COX)-2. The three major metabolic pathways of nabumetone are O-demethylation, reduction of the ketone to an alcohol, and an oxidative cleavage of the side-chain occurs to yield acetic acid derivatives. Essentially no unchanged nabumetone and < 1% of the major 6-MNA metabolite are excreted unchanged in the urine from which 80% of the dose can be recovered and another 10% in faeces. Nabumetone is clinically used mainly for the management of patients with osteoarthritis (OA) or rheumatoid arthritis (RA) to reduce pain and inflammation. The clinical efficacy of nabumetone has also been evaluated in patients with ankylosing spondylitis, soft tissue injuries and juvenile RA. The optimum oral dosage of nabumetone for OA patients is 1 g once daily, which is well tolerated. The therapeutic response is superior to placebo and similar to nonselective COX inhibitors. In RA patients, nabumetone 1 g at bedtime is optimal, but an additional 0.5-1 g can be administered in the morning for patients with persistent symptoms. In RA, nabumetone has shown a comparable clinical efficacy to aspirin (acetylsalicylic acid), diclofenac, piroxicam, ibuprofen and naproxen. Clinical trials and a decade of worldwide safety data and long-term postmarketing surveillance studies show that nabumetone is generally well tolerated. The most frequent adverse effects are those commonly seen with COX inhibitors, which include diarrhoea, dyspepsia, headache, abdominal pain and nausea. In common with other COX inhibitors, nabumetone may increase the risk of GI perforations, ulcerations and bleedings (PUBs). However, several studies show a low incidence of PUBs, and on a par with the numbers reported from studies with COX-2 selective inhibitors and considerably lower than for nonselective COX inhibitors. This has been attributed mainly to the non-acidic chemical properties of nabumetone but also to its COX-1/COX-2 inhibitor profile. Through its metabolite 6-MNA, nabumetone has a dose-related effect on platelet aggregation, but no effect on bleeding time in clinical studies. Furthermore, several short-term studies have shown little to no effect on renal function. Compared with COX-2 selective inhibitors, nabumetone exhibits similar anti-inflammatory and analgesic properties in patients with arthritis and there is no evidence of excess GI or other forms of complications to date.