Tissue distribution, urinary, fecal and biliary excretion of 14C bendazac L-lysine salt in rats

Pharmacological treatment strategies in age-related cataracts

Cataract is the major cause of blindness worldwide and at present the only approved treatment in many countries including the UK and USA is surgical removal of the lens. In other countries various anti-cataract drugs are available without proof of their efficacy. Research is continuing into the possible benefits of several groups of drugs and some vitamins. The first to be studied were sorbitol-lowering agents (aldose reductase inhibitors) based on the sorbitol hypothesis for diabetic cataract. Sorbitol-lowering agents have distinct effects in vitro and many of them delay the development of cataract in galactose-fed rats. A few delay cataract in diabetic rats but none have been proved effective in clinical trials, although these continue. Aspirin, paracetamol (acetaminophen) and ibuprofen delay diabetic cataract in rats, and have been shown to delay other experimental cataracts. Case-control studies from 3 continents indicate that these drugs, or at least aspirin, protect against cataract. Results of studies on all 3 drugs indicate a benefit even at low doses. Population-based studies did not identify any protection against early lens opacities but tiny opacities that do not impair vision are not a problem. Bendazac protects lens proteins in vitro and delays cataractogenesis in x-irradiated rats. In humans, it reached the clinical trial stage but most trials have been small and with subjective criteria of opacification. One objectively monitored trial suffered from a high drop-out rate. Other preparations studied less extensively include vitamins, aminoguanidine to prevent protein cross-linking in diabetes and agents designed to boost glutathione levels. It is probable that some agents which may delay or prevent cataract will be proved effective soon, and in the end there may be different drugs to delay cataract in different high risk groups. This is what might be expected of a multifactorial disease, although compounds that intervene in the final common pathways to cataract could have a broad efficacy.

Bendazac lysine. A review of its pharmacological properties and therapeutic potential in the management of cataracts

Bendazac is an oxyacetic acid with anti-inflammatory, antinecrotic, choleretic and antilipidaemic properties, but its principal effect is to inhibit the denaturation of proteins. The lysine salt, which is better absorbed than the parent compound after oral administration, has been evaluated as a treatment for cataract, a condition which appears to result mainly from the denaturation, aggregation and precipitation of proteins within the lens. Results from a very small number of preliminary studies using objective photographic and densitometric methods have suggested that oral bendazac lysine, usually at a dosage of 500 mg 3 times daily, can stabilise the progression of lens opacification in patients with cataract. Significant improvements in individual and mean visual acuities in treated patients have been reported by several studies, but this parameter is not universally accepted as a reliable index of lens status. Preliminary studies evaluating bendazac lysine 0.5% eyedrops have reported comparable results to those obtained with oral treatment. Overall, tolerability of the drug has been good in studies to date. A dose-related laxative effect and other gastrointestinal disturbances are the most common adverse effects associated with oral therapy, and a transient burning sensation is the most commonly reported symptom occurring with eyedrop application. Bendazac lysine is one of a number of agents which have been introduced for the management of cataract. Although the results of preliminary studies have suggested that the drug may be useful for delaying the progression of cataract, further clinical studies using proven objective methods are required to fully establish its value in the management of this condition and its long term tolerability.