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Levofloxacin, the bacteriologically active isomer of ofloxacin, has microbiologic activity against many pathogens common in human immunodeficiency virus (HIV)-infected patients, including Mycoplasma species which may be cofactors in the progression of HIV disease. The purpose of this phase I, double-blind, randomized (1:1), placebo-controlled trial was to evaluate the pharmacokinetics and safety of levofloxacin hemihydrate in 10 asymptomatic HIV-infected males. Plasma concentrations by chiral high-performance liquid chromatography (HPLC) were evaluated for 48 h after a single 350-mg oral dose, at morning predose during the multiple-dosing phase, and for 72 h at steady state after a week of 350 mg every 8 h orally. Mean +/- standard deviation levofloxacin pharmacokinetic parameters (by noncompartmental moment method) after multiple dosing were as follows: area under the concentration-time curve, 31.24 +/- 5.60 mg.h/liter; apparent total body clearance, 11.18 +/- 1.76 liters/h; renal clearance, 8.63 +/- 2.82 liters/h; steady-state volume of distribution, 104.10 +/- 12.48 liters; and effective half-life, 6.50 +/- 0.51 h. Single-dose parameters were not significantly different from the multiple-dose parameters, with the exception of peak concentrations in plasma, which were 4.79 +/- 1.00 and 6.92 +/- 1.56 mg/liter for single- and multiple-dose data, respectively. Essentially identical parameter values were obtained from curve-fitting analysis when the entire 13-day plasma concentration profiles of the subjects were analyzed simultaneously by a two-compartmental distribution model. Levofloxacin pharmacokinetics in HIV-infected patients remained linear upon multiple dosing. The dosing regimen studied provides levels in plasma and urine well above those found to be effective in vitro against pathogens common in HIV-infected patients. Levofloxacin was well- tolerated in this group of asymptomatic HIV-infected males: there were no statistically significant differences in adverse effects in the two groups (P = 0.22). Use of placebo control helped to differentiate disease-related adverse effects from those related to the study drug.

The effects of 15-and 5-ml doses of magnesium-aluminum hydroxide (MAH) and calcium carbonate (CC) antacids, respectively, on the bioavailability of ofloxacin after single oral 400-mg doses of ofloxacin were investigated in a 32-subject, randomized, crossover, open-label study. On four separate occasions, subjects received ofloxacin alone or antacid 24 h before, 2 h before, or 2 h after ofloxacin administration (n = 16 for each antacid). CC administration had no significant effect on the rate and extent of ofloxacin absorption regardless of the timing of antacid administration. A small but significant negative effect of MAH administration 2 h before ofloxacin administration was noted as evidenced by area under the curve and peak concentration in plasma data. Simultaneous administration of ofloxacin with either antacid was not investigated in this study. It appears that MAH and CC antacids in the doses used in this study generally do not interfere in a clinically significant manner with the bioavailability of ofloxacin, provided that an interval of at least 2 h separates the administration of these products.Ofloxacin is a synthetic carboxyquinolone antimicrobial agent which exhibits broad-spectrum in vitro bactericidal activities against gram-positive and gram-negative aerobes (8). The clinical efficacy of ofloxacin has been documented in patients with respiratory tract, upper and lower urinary tract, gonococcal and nongonococcal urethritis, and skin and soft tissue infections (8,14).Coadministration of some antacids and sucralfate has resulted in diminished absorption of several of the carboxyquinolones. This phenomenon has been reported to be due to the formation of insoluble chelates in the gastrointestinal tract (5-7, 9-12). Although the majority of these interaction studies have investigated the quinolone ciprofloxacin, four reports have suggested the existence of a similar interaction between antacids and ofloxacin (7,12; G. Hoffken 19:848-850, 1987).This study was designed to rigorously characterize the interaction potential between ofloxacin and two commonly used antacid preparations: (i) magnesium-aluminum hydroxide (Maalox; Rorer Pharmaceutical Corp., Fort Washington, Pa.) and (ii) calcium carbonate (Titralac; 3M Riker, St. Paul, Minn.).The study was approved by the Human Subjects Research Committee, Hennepin County Medical Center. Thirty-two normal, healthy male volunteers who participated in the study were between the ages of 18 and 40 years, and all subjects gave written, informed consent prior to participation. The patients were healthy, as determined by comprehensive medical history, physical examination, electrocardiography, and laboratory profiles. None of the subjects was taking medications within 1 week before or during the study. None of the subjects had a history or current evidence of * Corresponding author. significant renal, hepatic, cardiovascular, hematologic, neurologic, psychiatric, respiratory, or metabolic disease.A parallel study design was followed wherein 16 subjects were rando...

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The safety and pharmacokinetics of ofloxacin in 48 healthy male volunteers were studied in a two-center, randomized, double-blind, placebo-controlled study. Ofloxacin (200 or 400 mg) or placebo was administered as 1-h infusions every 12 h for 7 days. Plasma ofloxacin concentrations were measured by high-performance liquid chromatography. Mean harmonic half-lives ranged from 4.28 to 4.98 h in the 200-mg dosing group and from 5.06 to 6.67 h in the 400-mg dosing group. Intragroup comparisons of trough plasma concentration-versus-time data from study days 2 through 7 revealed that steady state was achieved by day 2 of both multiple-dose regimens. Intergroup comparisons of mean harmonic half-lives, the areas under the concentration-time curve from 0 to 12 and 0 to 60 h, clearance, and apparent volume of distribution (area method) revealed that the pharmacokinetics of ofloxacin are dose independent. Both ofloxacin dosage regimens appeared to be reasonably well tolerated. The two dosage regimens of ofloxacin, 200 or 400 mg every 12 h, appear to be safe and provide serum drug concentrations in excess of the MICs for most susceptible pathogens over the entire dosing interval.