Accumulation of new quinolones in the blood of elderly patients

Quinolones in the aged

Pharmacokinetic studies of fluoroquinolone antibacterials generally demonstrate some quantitative alterations in elderly compared with younger populations. The most common observations are an increased maximal plasma drug concentration and area under the concentration-time curve, which are primarily attributable to the 10 to 15% decrease in lean body mass in the elderly. For quinolones excreted primarily by the renal route, there is a prolongation in elimination half-life correlated with the aging-associated decline in creatinine clearance. Quinolones with major routes of nonrenal clearance will not usually show a prolongation in half-life because of compensatory relative increases in nonrenal mechanisms. Alterations directly attributable to aging alone, however, are minor, and vary between different quinolones. They do not justify a consistent need for dosage alterations on the basis of age alone. Agents with primarily renal excretion, such as ofloxacin or levofloxacin, may require dosage adjustment in the very elderly or the frail elderly, if significant decreases in creatinine clearance are present. No age-related differences in adverse effects of fluoroquinolones have been reported. Studies in both community-dwelling and institutionalised elderly populations have consistently shown quinolones to be as effective as comparative parenteral or oral therapy. While elderly populations may be at greater risk of adverse effects because of comorbidities and concurrent therapies, an increased occurrence of adverse events in elderly populations receiving quinolone antimicrobials relative to younger populations has not been reported.

Photosensitivity reactions caused by lomefloxacin hydrochloride: a multicenter survey

The photosensitivity effect of lomefloxacin hydrochloride (LFLX) was investigated in terms of patient background factors (sex, age, underlying disease, complications, history, occupation, and residential condition, etc.), treatment factors (daily dosage of LFLX, duration of treatment, total dose, concomitant drugs, and previous medication, etc.), and correlations among them. In 100 institutions throughout Japan, 4,284 patients were enrolled over a period of 2 years, beginning in October 1991, avoiding the accumulation of patients in any specific season. Since 8 patients did not visit again after enrollment, the clinical records of 4,276 patients were analyzed. Photosensitivity in 44 patients was found (1.03%), but the symptoms in most patients were not severe and improved after discontinuation of LFLX treatment. The photosensitivity reaction was more prevalent in patients who were 60 years of age and older with concomitant diseases and complications, in patients treated with a total amount of 20 g and more of LFLX for 30 days or longer, and in patients with a history of previous treatment with quinolone drugs. Although the incidence and degree of the photosensitivity reaction vary significantly among new quinolone drugs, every quinolone drug is potentially phototoxic. In particular, long-term use of LFLX should be avoided, and patients taking LFLX should be advised to abstain from prolonged exposure to sunlight.

Enoxacin: a reappraisal of its clinical efficacy in the treatment of genitourinary tract infections

Enoxacin is a 6-fluoronaphthyridinone antibacterial agent with good in vitro activity against Neisseria gonorrhoeae and most Gram-negative urinary tract pathogens. It is less active in vitro against Acinetobacter spp., Pseudomonas aeruginosa, and most Gram-positive bacteria, than against Gram-negative organisms. Enoxacin is rapidly absorbed, with a high oral bioavailability (87 to 91%). Of the absorbed dose, 44 to 56% is excreted unchanged in the urine, with peak urinary concentrations (>500 mg/L within 4 hours) remaining high (>100 mg/L) for up to 24 hours, sufficient to inhibit most urinary tract pathogens. Single (400 mg) and multiple oral dose regimens (100 to 600 mg twice or 3 times daily for 5 to 14 days) of enoxacin are as effective for the treatment of patients with complicated or uncomplicated urinary tract infections as other antibacterial agents such as amoxicillin, cefuroxime axetil, cotrimoxazole (trimethoprim-sulfamethoxazole) or trimethoprim. Noncomparative data suggest that enoxacin is also an effective agent for the treatment of prostatitis. Single 400 mgoral doses of enoxacin produce >/- 95% bacteriological cure rates in gonococcal infections, comparable to those produced by single intramuscular doses of ceftriaxone 250 mg. Perioperative doses of oral enoxacin 200 mg provide effective prophylaxis against postoperative bacteriuria after transurethral resection of the prostate. Concomitant administration of enoxacin with a number of commonly used therapeutic agents (e.g. antacids, methylxanthines, warfarin) affects the pharmacokinetic properties of either enoxacin or the coadministered agents. Enoxacin is reasonably well tolerated, with the incidence of adverse experiences ranging from 0 to 24%. Adverse events are mainly gastrointestinal, neurological or dermatological and resolve with minimal intervention. Overall, although enoxacin exhibits a number of clinical characteristics that are similar to those of other agents for the treatment of genitourinary tract infections, the advantages offered by this agent generally do not outweigh those of alternative fluoroquinolone agents. Thus, it is likely to prove to be yet another addition to the list of agents available for the management of these infections.