Toxic optic neuropathy caused by benoxaprofen

Drug reactions and interactions in the elderly patient

Elderly patients take a large number of drugs, especially psychoactive agents, and polypharmacy seems to be the rule in acute hospital settings and in institutions alike. Knowledge about alteration in drug response, with aging, is still at a preliminary and investigational stage, and the problem is compounded by the fact that there are relatively few drugs for which a special geriatric dosage is recommended.

It appears to be common practice to keep the elderly in “chemical strait jackets” in some institutions, with emphasis on the use of antipsychotic and sedative/hypnotic combinations. Use of these agents has reached such proportions in Britain and America that it has become necessary to warn that antipsychotic drugs should be used only to treat acute behavior disorders in such patients.

The potential for drug-drug interactions in the elderly patient is, therefore, large, and, in the community, the most common categories of prescribed drugs taken by the elderly are psychotropics, diuretics, and antipyretic/analgesics. In addition, analgesics and laxatives are often taken as nonprescribed medicines. Poor compliance with medication instructions, hoarding of drugs, and inadequate knowledge of the purpose of medication are very common. The eventual sequel to these factors is hospitalization; diuretics, hypotensives, antiparkinsonian agents, and psychotropics carry the greatest risk of evoking serious adverse drug reactions.

Some specific drugs or groups of drugs present peculiar problems to the aged patient; these agents are relatively few in number and include digoxin, hypotensives, diuretics, nonsteroidal antiinflammatory agents, benzodiazepines, phenothiazines, lithium, and other psychoactive drugs. Currently, lithium and the antirheumatoid agent benoxaprofen are causing much concern in regard to the elderly. With lithium, there are adverse effects suggestive of neurotoxicity, and interactions with concurrent neuroleptic and/or antidepressant therapy, diuretics, and low salt diet are involved. As for benoxaprofen, reports in the past few months have causally linked this drug with fatal cholestatic jaundice and other serious reactions; this drug has now been withdrawn from clinical use.

Health professionals must use extreme care when treating an elderly patient with drugs.

Pharmacology, clinical efficacy, and adverse effects of the nonsteroidal anti-inflammatory agent benoxaprofen

Benoxaprofen is a nonsteroidal anti-inflammatory agent that belongs to the arylalkanoic acid class of antirheumatic drugs. Animal studies have demonstrated that it has analgesic, antipyretic, and anti-inflammatory properties. Although benoxaprofen is a relatively weak inhibitor of cyclo-oxygenase in in vitro systems, inhibits lipoxygenase in other systems, and inhibits monocyte migration in some animal models of inflammation, it has not been established that it is unique with regard to these actions. Benoxaprofen undergoes hepatic metabolism via glucuronidation as the primary route of elimination and has a half-life of 28-35 hr. Clinical trials have demonstrated that its analgesic and anti-inflammatory properties are useful in the management of the signs and symptoms of rheumatoid arthritis and osteoarthritis. Once daily dosing of 300-600 mg is effective for many patients. In addition to gastrointestinal intolerance, photosensitivity and onycholysis are the most frequent adverse effects encountered. Recent reports of fatal cholestatic jaundice often associated with nephrotoxicity led to the withdrawal of benoxaprofen from world markets. It is uncertain whether it will once again be available for clinical use.