Antirheumatic activity of fenclofenac

The value of C-reactive protein measurement in rheumatoid arthritis

Since 1973, assessment of serum concentrations of C-reactive protein (CRP) has been advocated as a objective measure of disease activity in rheumatoid arthritis (RA). Our review of clinical experience with CRP measurement suggests it has at least two important roles to play in the management of RA. First, persistently elevated CRP levels have prognostic value. In general, such elevated levels are found in those patients who are at greater risk for continuing joint deterioration and therefore may need more aggressive treatment and supportive care. Second, in general, improvement in CRP levels is an objective indication that a drug has produced a beneficial effect and thus may be useful to the physician for monitoring effects of therapy. Since CRP may be elevated in a number of conditions besides RA, a diagnosis of RA must be made before using CRP as a prognostic factor.

A review of selected investigational nonsteroidal antiinflammatory drugs of the 1980s

We reviewed the literature on 7 investigational nonsteroidal antiinflammatory drugs (NSAIDs): fenbufen, flurbiprofen, tiaprofenic acid, diclofenac, fenclofenac, etodolac and proquazone. These drugs all appear to be at least as effective as currently marketed NSAIDs. Toxicity reported with these newer agents is similar to that seen with other drugs in this class, with gastrointestinal complaints being most commonly reported. The frequency of gastritis and the extent of gastrointestinal microbleeding are less than what occur with aspirin therapy. Fenclofenac may affect thyroid function tests, an effect not noted with other NSAIDs. Proquazone and fenclofenac may have some effect on immunologic function similar to those of slow-acting antirheumatic drugs. These drugs decrease immunoglobulins, rheumatoid factor and C-reactive protein. The place for these drugs in the management of rheumatic diseases has yet to be defined. They may prove to be more beneficial than currently marketed drugs for some patients.

Non-steroidal anti-inflammatory drugs. Current status and rational therapeutic use

Aspirin (acetylsalicylic acid), the first of the NSAIDs (introduced in 1899), was initially never referred to as an anti-inflammatory agent. It was the advent of cortisone in 1949 that demonstrated dramatically that corticosteroids had anti-inflammatory properties and the term 'non-steroidal anti-inflammatory drug' was first used when phenylbutazone was introduced 3 years later. Since then, the NSAIDs have proliferated. There is to date no good evidence that they halt progression of rheumatoid disease, but by easing pain and diminishing swelling they make life much easier in osteoarthrosis, rheumatoid arthritis and many other types of arthritis, and are the drugs of first choice in acute gout. Their mode (or modes) of action are obscure and though inhibition of cyclo-oxygenase (prostaglandin synthetase) is clearly important, other mechanisms are also involved. The assessment of the anti-inflammatory action of these agents has received considerable attention in clinical trials because, whatever their action may be in experimental animal models, their action in inflamed joints in human patients must be ascertained, since there may be little parallel between the two. Different experimental animal models give different results with various agents and often bear little relation to their therapeutic action in man. No attempt has been made here to review in depth all the NSAIDs that have appeared since 1952. All have anti-inflammatory and analgesic activity and all can cause gastrointestinal side effects, though effectiveness and toxicity vary from drug to drug and patient to patient, there being very great interpatient variability. Non-reactors, patients who apparently fail to respond to certain agents, need further study, for it seems that these subjects may metabolise these agents differently from others. Considerable ingenuity has been shown not only in evolving new NSAIDs but in finding new ways of administering them. The number and variety of NSAIDs in their various forms varies greatly from country to country, depending largely on the regulatory bodies of those countries. In the meantime, the search for a better, less toxic compound continues with the hope that one may be found which has a deeper and more basic action on the underlying disease process.

Pharmacokinetics of fenclofenac in children with juvenile rheumatoid arthritis

Twenty eight children (age range 3-17 years) with juvenile rheumatoid arthritis (JRA) received fenclofenac 10-25 mg/kg body weight daily on an open basis. Pharmacokinetic analysis was undertaken on plasma fenclofenac levels measured during the first 3 weeks of treatment. The peak concentration after the first dose was achieved in 2-8 h in non-fasting subjects and was linearly related to dose. The plasma level then decayed biexponentially, as in adults, the initial distribution phase extending to about 12 h after dosing. After treatment for 18 days, blood samples were taken during the 96 h following the last dose of the drug to define the steady state elimination profile. The elimination half-life was 25.4 +/- 7.9 h (n = 17) and did not appear to be dependent on the daily dosage. A therapeutic drug concentration of greater than or equal to 100 micrograms/ml emerged from subjective and objective estimates of the response to treatment and measurement of steady state fenclofenac concentration. Treatment response could be more accurately predicted with the aid of drug concentrations than from dosage alone, although the dose and the steady state drug concentration were positively and linearly correlated (r = 0.61, p less than 0.01). Of 16 children receiving doses in excess of 20 mg/kg/day, 3 experienced dose-related adverse effects, increased serum transaminase activity, vertigo and dyspnoea.