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Biomedical subjects

A H Heller

Publications and source records attributed to A H Heller.

At least 19 recordsLinked to original sources
PubMed2004

Intra- and intercontinental molecular variability of an Alu insertion in the 3' untranslated region of the LDLR gene.

One-hundred three individuals from two Mongolian, two Siberian, and ten native American populations were studied in relation to a 340-bp sequence from an Alu insertion located in the 3' untranslated region of the LDLR gene. Seven haplotypes have been determined, and haplotype B1 was the most common, accounting for about half the sequences found. In general, diversity values are quite high, about 2.5 times higher than those found in other autosomal Alu sequences. Almost all (93%) of the variability occurs at the intrapopulation level, but the greatest among-group differentiation (6-8%) was found when we grouped in a single population all Native Americans plus Siberian Eskimos and Chukchi and compared them with Mongolians. This result is compatible with earlier mtDNA and Y-chromosome suggestions of a single origin for the first colonizers of the American continent. With this nuclear locus it was not possible to broadly distinguish between Central and South American natives. No evidence of selection or marked demographic changes was obtained with these data.

3' Untranslated Regions↗
PubMed2001

Influence of gender on the pharmacokinetics, safety, and tolerability of cerivastatin in healthy adults.

The pharmacokinetics, safety, and tolerability of cerivastatin, a synthetic HMG-CoA reductase inhibitor were studied in 49 healthy volunteers. In this double-blind, parallel group, multiple-dose study, volunteers were randomized as age-matched, male-female pairs and stratified into younger (18-65 years, premenopausal females) or older (65-85 years, postmenopausal females) groups. Thirty-two (16 female, 16 male) subjects received 0.2 mg cerivastatin daily for 7 days; 17 received placebo. Between all males and females, no differences in cerivastatin pharmacokinetics were observed. The AUCnorm in older females was 21% higher than in older males, while the AUCnorm in younger females was 26% lower than in younger males. The Cmax in older females was 30% higher than in age-matched males or younger males and females. All other pharmacokinetic parameters, including half-life, tmax, accumulation ratios, and steady state plasma levels were similar in all treatment groups. The most common adverse events, including headache (4), dyspepsia (4), and rash (4), were equally distributed between groups. Treatment-emergent elevations (< 2 x ULN) in creatine kinase occurred in one subject. Transaminase elevations occurred in nine subjects, most were less than 3 x ULN, and were equally distributed between groups. In conclusion, cerivastatin was well tolerated. The minor differences in the pharmacokinetics of cerivastatin 0.2 mg between genders does not require modification of dosage.

Adult↗
PubMed2001

The influence of age and gender on the pharmacokinetics of moxifloxacin.

OBJECTIVE: Moxifloxacin is a new 8-methoxyfluoroquinolone with a broad antibacterial spectrum. The purpose of the present study was to determine the effects of age and gender on pharmacokinetics, surrogate pharmacodynamics, safety and tolerability of a single dose of moxifloxacin. DESIGN: This was a randomised, double-blind, placebo-controlled, parallel-group single dose trial in young and elderly healthy volunteers. PATIENTS AND PARTICIPANTS: The study included 36 volunteers in 3 age and gender groups: young males (mean age 32 years), elderly males (mean age 74 years), and elderly females (mean age 74 years). METHODS: Participants received either a single 200mg oral dose of moxifloxacin (8/group) or placebo (4/group). Blood samples for moxifloxacin pharmacokinetics were obtained before and up to 48 hours after administration. Urine samples were collected for pharmacokinetics, and volunteers were monitored for clinical adverse events and laboratory abnormalities. RESULTS: Maximum plasma concentration (Cmax) and area under the plasma concentration-time curve (AUC) were higher in elderly females than in elderly males; however, when normalised for bodyweight, these pharmacokinetic parameters were not significantly different between the groups. Moreover, the plasma pharmacokinetics in elderly males were not meaningfully different from those in young males. Elimination half-life averaged 12 to 13 hours for the 3 groups. Surrogate pharmacodynamic measures were derived using AUC/MIC (minimal inhibitory concentration) and Cmax/MIC ratios. These assessments indicated that, given the linear pharmacokinetics of moxifloxacin previously demonstrated, a dose of 400mg would produce mean Cmax/MIC values in the different subgroups ranging from 10.4 to 15.4 for an MIC of 0.25, and 20.8 to 30.8 for an MIC of 0.125. The corresponding ranges of projected AUC/MIC ratios would be 112 to 158 for an MIC of 0.25, and 224 to 314 for an MIC of 0.125. The accepted target values of AUC/MIC and Cmax/MIC for quinolones are 125 and 10, respectively. There were no serious adverse events or differences in adverse event profiles between the groups. CONCLUSIONS: Moxifloxacin does not exhibit age- or gender-dependent pharmacokinetics. Oral doses of 200 to 400mg yield effective antibacterial concentrations on the first day of administration.

Administration, Oral↗
PubMed2000

PhRMA perspective on population and individual bioequivalence.

The Food and Drug Administration (FDA) issued a second-draft guidance in August 1999 on the subject of in vivo bioequivalence, which is based on the concepts of individual and population bioequivalence (IBE and PBE, respectively). The intention of this guidance is to replace the 1992 guidance that requires that in vivo bioequivalence be demonstrated by average bioequivalence (ABE). Although the concepts of population and individual bioequivalence are intuitively reasonable, a detailed review of the literature has not uncovered clinical evidence to justify the additional burden to the innovator and generic companies as well as the consumer that the new guidelines would impose. The criteria for bioequivalence described in the draft guidance employ aggregate statistics that combine information about differences in bioavailability between formulation means and differences in bioavailability variation of formulations between and within subjects. The purely technical aspects of the statistical approach are reasonably sound. However, PhRMA believes that important operational issues remain that need to be resolved before any changes to current practice are implemented. PhRMA believes that the ideals of prescribability and switchability are intuitively reasonable, but it is uncertain of the extent to which the proposed guidance can achieve these goals. It is not clear whether the attainment of such goals is necessary in the evaluation of bioequivalence given the role this plays in drug development, and the lack of clinical evidence argues against a pressing need to change current practice. PhRMA is concerned that the trade-off offered by the aggregate criteria may ultimately represent more harm than good to the public interest. PhRMA recommends more rigorous evaluation of methods based on two-way crossover designs before moving to methods that require more complex designs. One such method is identified herein and contains procedures for estimating prescribability and switchability. The possibility of a phase-in or trial period to collect replicate crossover data to further evaluate IBE and PBE and possibly allow market access based on these criteria as they are being evaluated has been proposed. PhRMA believes this is unprecedented and will offer little additional information beyond that which can be obtained by simulation or has already been collected by the FDA. Simulation studies have the advantage of allowing evaluation of the sensitivity of various procedures to represent the data patterns as created within the simulation. Operating characteristics by which proposed criteria can be adequately judged have not yet been defined. The limitations of ABE for highly variable drugs and narrow therapeutic drugs are well appreciated and may be addressed by means other than a wholesale change in the current criteria.

Humans↗
PubMed1999

Pharmacodynamics, safety, tolerability, and pharmacokinetics of the 0.8-mg dose of cerivastatin in patients with primary hypercholesterolemia.

Cerivastatin is a third generation hydroxy-methyl-glutaryl-Co-enzyme A (HMG-CoA) reductase inhibitor proven to lower low-density lipoprotein (LDL) cholesterol 28% to 31% in patients with primary hypercholesterolemia when given at 0.3 mg/day. This study evaluates the safety, tolerability, pharmacodynamics, and pharmacokinetics of cerivastatin 0.8 mg once daily for 4 weeks. In this randomized, double-blind, placebo-controlled parallel group trial conducted at 2 study centers, 41 patients (63% women) with primary hypercholesterolemia were placed on an American Heart Association Step 1 diet for 4 weeks. Single-blind placebo was administered for the final 2 weeks, before randomization. Patients received cerivastatin 0.8 mg (n = 28) or placebo (n = 13) once each evening for 28 days. Cerivastatin at 0.8 mg daily was well tolerated. No discontinuations occurred during the study. Adverse events were mild and transient. One cerivastatin-treated patient experienced asymptomatic creatinine kinase, 8x the upper limit of normal (ULN) elevation on the last day of the study, which resolved 6 days after the completion of the study. Cerivastatin 0.8 mg daily significantly reduced LDL cholesterol compared with placebo (-44.0 +/- 2.0% vs 2.2 +/- 2.8%, p <0.0001); total cholesterol (-30.8 +/- 1.4% vs 2.6 +/- 2.1%, p <0.0001), triglycerides (-11.2 +/- 5.9% vs 15.9 +/- 8.6%, p <0.02), but did not significantly alter high-density lipoprotein (HDL) cholesterol (3.2 +/- 2.1% vs -1.2 +/- 3.1%, p = NS). The pharmacokinetics of the 0.8-mg dose revealed dose proportional elevations in the 24-hour area under the curve and maximum plasma concentration relative to 0.3- and 0.4-mg doses with no change in time to maximum concentration or the elimination half-life in plasma. The increased efficacy and lack of clinically significant laboratory abnormalities or adverse events demonstrates a need for a large long-term study to confirm the safety and efficacy of this dose of cerivastatin.

Cholesterol, LDL↗
PubMed1999

Oral bioequivalence of three ciprofloxacin formulations following single-dose administration: 500 mg tablet compared with 500 mg/10 mL or 500 mg/5 mL suspension and the effect of food on the absorption of ciprofloxacin oral suspension.

The oral bioequivalence and tolerability of two ciprofloxacin formulations (tablet and suspension) and the effect of food on the absorption of ciprofloxacin oral suspension were investigated. Sixty-eight young, healthy male subjects participated in two separate, randomized, crossover studies. In study 1, ciprofloxacin as a single 500 mg tablet or as 500 mg/10 mL oral suspension was administered in a fasted state on day 1. In study 2, subjects participated in a three-way crossover study in which ciprofloxacin suspension was administered as 500 mg/10 mL in a fasted state, or 500 mg/10 mL with food, or 500 mg/5 mL in a fasted state. Plasma ciprofloxacin concentrations were measured by high-performance liquid chromatography. Standard pharmacokinetic parameters were estimated using non-compartmental methods. In study 1, geometric mean Cmax values of ciprofloxacin following the single 500 mg tablet and 500 mg/10 mL suspension doses were 2.36 and 2.18 mg/L, respectively; corresponding geometric mean t(max) values were 1.1 and 1.6 h, respectively. Geometric mean AUC(0-infinity) values were 12.0 and 11.8 mg x h/L, respectively. In study 2, geometric least squares mean Cmax values following ciprofloxacin 500 mg/10 mL and 500 mg/5 mL suspension during fasted conditions were 1.54 and 1.59 mg/L, respectively. Corresponding geometric least squares mean AUC(0-infinity) values were 7.3 and 8.0 mg x h/L. Administration of ciprofloxacin 500 mg/10 mL suspension, in either a fasted or fed state, was not associated with significant changes in Cmax (1.54 mg/L for fasted vs 1.37 mg/L for fed) or AUC(0-infinity) values (7.28 mg x h/L for fasted vs 8.19 mg x h/L for fed). Each ciprofloxacin formulation was well tolerated for the duration of each study. These studies demonstrated bioequivalence between ciprofloxacin 500 mg tablet and two strengths of ciprofloxacin suspension (500 mg/10 mL and 500 mg/5 mL). Bioavailability was unaltered by food.

Administration, Oral↗
PubMed1999

Pharmacokinetics of a once-daily oral dose of moxifloxacin (Bay 12-8039), a new enantiomerically pure 8-methoxy quinolone.

The pharmacokinetics, safety, and tolerability of oral moxifloxacin, a new 8-methoxy quinolone, were assessed in a randomized, double-blind, placebo-controlled study in which healthy male and female volunteers received either 400 mg of moxifloxacin once daily (n = 10) or a placebo once daily (n = 5) for 10 days. Plasma moxifloxacin concentrations on days 1 and 10 were measured by high-performance liquid chromatography and fluorometric detection. Standard pharmacokinetic parameters were estimated by noncompartmental methods. Natural logarithmic estimates for each pharmacokinetic variable of each subject were analyzed by a two-way analysis of variance. Hematology, blood chemistry, vital signs, and adverse events were monitored, and electrocardiograms (ECG) were performed. Plasma moxifloxacin concentrations of predicted therapeutic relevance were achieved in this study. For day 1, the mean maximum concentration of drug in serum (C(max)) and the area under the concentration-time curve from 0 to 24 h (AUC(0-24)) were 3. 4 mg/liter and 30.2 mg. h/liter, respectively. Corresponding means on day 10 were 4.5 mg/liter and 48 mg. h/liter, respectively. On day 10, the mean elimination half-life was approximately 12 h. Plasma moxifloxacin concentrations exceeded the MIC for Streptococcus pneumoniae throughout the 24-h dosing period. The day 1 and day 10 mean AUC/MIC ratios were 121 and 192, respectively, and the mean C(max)/MIC ratios were 13 and 18, respectively. Moxifloxacin was well tolerated; no clinically relevant changes in the standard laboratory tests, vital signs, or ECG were observed. Pharmacokinetic parameters demonstrated linearity, and estimates of pharmacokinetic/pharmacodynamic ratios (AUC/MIC and C(max)/MIC) indicate that the regimen of 400-mg once daily should be effective for treating a variety of infections. Moxifloxacin was found to be safe and well tolerated in healthy volunteers when it was given as a single daily 400-mg dose for 10 days.

Adolescent↗
PubMed1998

Preclinical and clinical pharmacology of cerivastatin.

Cerivastatin, a new, entirely synthetic, and enantiomerically pure 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitor, is pharmacologically potent and hepatically selective, with an uncomplicated pharmacokinetic profile. In vitro and acute in vivo studies in animals demonstrated that cerivastatin is markedly more pharmacologically potent than other statins. In rats and dogs, cerivastatin inhibited hepatic cholesterol synthesis at concentrations 100-150 times lower than lovastatin. Cerivastatin's potent inhibition of HMG-CoA reductase (the rate-limiting step in cholesterol biosynthesis) is confirmed by its cholesterol-lowering properties, combined with significant triglyceride-decreasing effects, and dose-dependent increases in low-density lipoprotein (LDL) receptor binding in the liver. The antiatherogenic effects of cerivastatin extend beyond serum lipid and lipoprotein reductions to potent inhibition of migration of smooth muscle cells in vitro and reductions in the accumulation of cholesterol ester in the arterial tissue of rabbits. The high pharmacologic potency of cerivastatin, coupled with high liver selectivity, enable cerivastatin to be administered at 1-5% of the dose of currently available HMG-CoA reductase inhibitors. At ultra-low doses in the range 0.01-0.8 mg/day, cerivastatin proved to be both safe and well tolerated when administered to healthy volunteers in a series of ascending single- and multiple-dose studies. Cerivastatin has an uncomplicated pharmacokinetic profile; it can be administered to both young and elderly patients, male and female, without the need for dosage adjustments. Because no clinically significant pharmacokinetic drug interactions occur with cerivastatin, it may be the preferred HMG-CoA reductase inhibitor for patients on multiple-drug therapy including warfarin and digoxin.

Animals↗
PubMed1998

Influence of age on the safety, tolerability, and pharmacokinetics of the novel HMG-CoA reductase inhibitor cerivastatin in healthy male volunteers.

The safety, tolerability, and pharmacokinetics of cerivastatin, a novel, synthetic, potent, and highly selective HMG-CoA reductase inhibitor, were studied in 48 young and elderly male volunteers in a randomized, double-blind, placebo-controlled study. Eight men ranging from 18 to 38 years of age (young) and 15 men ranging from 65 to 78 years of age (elderly) received 0.1-mg cerivastatin tablets daily for 7 days. The remaining subjects (8 young and 17 elderly) received matching placebo tablets. Cerivastatin was well tolerated in elderly and young subjects. Adverse events were mild and occurred less frequently in the participants receiving cerivastatin than in those receiving placebo. In those participants given cerivastatin, the incidence of adverse events was similar for both age groups (4 of 8 young subjects and 8 of 15 elderly subjects). Transient and mild elevations in creatine kinase and transaminase levels were evenly distributed across the cerivastatin and placebo groups. Pharmacokinetic parameters, including area under the concentration curve (AUC), peak plasma concentration (Cmax), time to Cmax (tmax), and elimination half-life (t1/2), were similar between the two age groups. The mean elimination t1/2 for both groups was approximately 4 hours. These results indicate that cerivastatin is well tolerated in elderly male volunteers at a dosage of 0.1 mg/day. Further, the pharmacokinetics of cerivastatin are not altered as a consequence of age. Dose adjustment is therefore not required in elderly men.

Adult↗
PubMed1996

Effect of ciprofloxacin on the pharmacokinetics and pharmacodynamics of warfarin.

To determine if ciprofloxacin therapy alters the response to warfarin treatment, 36 adult patients attending three university-affiliated outpatient anticoagulation clinics randomly received a 12-day course of ciprofloxacin (750 mg twice daily) and a 12-day course of placebo; each course was separated by a 2-week washout period. Prothrombin times (PTs), concentrations of S-warfarin and R-warfarin (the isomers of warfarin), and concentrations of clotting factors II and VII were determined three times weekly for 9 weeks. By day 12 of ciprofloxacin therapy, concentrations of S-warfarin remained unchanged compared with those after placebo therapy, but R-warfarin concentrations increased significantly (1.15 times those after placebo therapy; P = .001); concentrations of clotting factors II and VII decreased (0.903 and 0.872 times those after placebo therapy, respectively, P < or = .020). The mean PT ratio after 12 days of ciprofloxacin therapy increased slightly (1.032 times that after placebo therapy; P = .057), but no patient had bleeding or a change in PT that required alteration in warfarin or ciprofloxacin therapy. We conclude that warfarin therapy is not a contraindication to the use of ciprofloxacin.

Adult↗
PubMed1996

Pharmacokinetics of intravenous ciprofloxacin in normal and renally impaired subjects.

The pharmacokinetics of intravenous ciprofloxacin and its metabolites were characterized in 42 subjects with various degrees of renal function (group 1, Clcr (mL/min/1.73 m2) > 90, n = 10; group 2, Clcr 61-90, n = 11; group 3, Clcr 31-60, n = 11; group 4, Clcr < or = 30, n = 10). The dosage regimens were-groups 1 and 2: 400 mg i.v. at 8 hourly intervals; group 3: 400 mg i.v. at 12 hourly intervals and group 4: 300 mg i.v. at 12 hourly intervals. Subjects received a single dose on days 1 and 5 and multiple doses on days 2-4. Multiple plasma and urine samples were collected on days 1 and 5 for the analysis of ciprofloxacin and its metabolites (M1, M2 and M3). Plasma concentrations (Cmax and AUC) of ciprofloxacin and its M1 and M2 metabolites were significantly increased in subjects with reduced Clcr values (Clcr < 60 mL/min/1.73 m2) compared with normal subjects (Clcr > 90 mL/min/1.73 m2). A positive correlation was observed between ciprofloxacin clearance (Cl) and Clcr with a slope of 0.29 (r2 = 0.78) and between renal clearance (Clr) and Clcr with a slope of 0.19 (r2 = 0.84). For patients with severe infections a dosage regimen of 400 mg iv 8 hourly is appropriate in patients with Clcr > 60 mL/min/1.73 m2. In patients with Clcr values of 31-60 mL/min/1.73 m2 a dosage regimen of 400 mg 12 hourly provides similar plasma concentrations to those observed for subjects with Clcr 61-90 mL/min/1.73 m2 receiving 400 mg 8 hourly. Based on modeling of the plasma concentrations in subjects with Clcr < or = 30 ml/min/1.73 m2, a dosage regimen of 400 mg every 24 h will provide plasma concentrations similar to those observed in subjects with Clcr between 61-90 mL/min/1.73 m2 given 400 mg every 8 h.

Adult↗
PubMed1995

Pharmacokinetics of high-dose intravenous ciprofloxacin in young and elderly and in male and female subjects.

The effects of age and gender on the pharmacokinetics of high-dose intravenous ciprofloxacin in a healthy volunteer study were investigated. Plasma ciprofloxacin concentrations were higher in the elderly than in the young, and the pharmacokinetic parameters were not significantly different between the genders. Ciprofloxacin was well tolerated, with the majority of adverse events related to local reactions at the IV site.

Adolescent↗
PubMed1994

Comparative crossover assessment of serum bactericidal activity and pharmacokinetics of ciprofloxacin and ofloxacin.

The study compared the pharmacokinetics and pharmacodynamics of ciprofloxacin and ofloxacin in 12 healthy male volunteers with normal renal function. Each volunteer received oral ciprofloxacin 500 mg, intravenous (i.v.) ciprofloxacin 400 mg, oral ofloxacin 400 mg, or i.v. ofloxacin 400 mg in a randomized, double-blind, crossover design with a one-week 'washout' period between doses. Mean peak serum concentrations were 4.48 and 5.44 mg/L for i.v. ciprofloxacin and ofloxacin, respectively. For the oral regimens, mean peak serum concentrations were 2.45 mg/L for ciprofloxacin and 4.44 mg/L for ofloxacin. Minimum bactericidal concentrations (MBC) and serum bactericidal activity (SBA) for each drug were measured against five strains of each of the following species: Escherichia coli, Klebsiella pneumoniae, Enterobacter aerogenes, Pseudomonas aeruginosa, Acinetobacter anitratus, Haemophilus influenzae, Staphylococcus aureus, and Streptococcus pneumoniae, using the microdilution method of the National Committee for Clinical Laboratory Standards (NCCLS). Ciprofloxacin was more active in vitro than ofloxacin against the tested species of Enterobacteriaceae and P. aeruginosa, while ofloxacin was slightly more active against A. anitratus. MBCs for the two drugs were similar for H. influenzae and S. aureus. Oral and i.v. ciprofloxacin in the doses given resulted in nearly equivalent SBA. Similarly, oral and i.v. ofloxacin had nearly equivalent SBA. For the i.v. and oral regimens of both agents, peak SBA was > or = 2 throughout the 12-hour test period against the Enterobacteriaceae and H. influenzae. At peak concentrations, both drugs had modest SBA against P. aeruginosa, A. anitratus, and S. aureus but little or no activity 8 and 12 h after dosing.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1994

Comparative pharmacokinetics and safety of ciprofloxacin 400 mg i.v. thrice daily versus 750 mg po twice daily.

Comparative pharmacokinetics of i.v. and oral ciprofloxacin was studied in 24 healthy male subjects given 400 mg i.v. tds or 750 mg po bd in a randomized, double-blind, placebo controlled, crossover fashion with at least a 10 day washout period. Blood and urine samples were obtained following the first (single dose) and last (steady state) dose in each treatment period. After single dosing and under steady state conditions, the calculated 24 h area under the serum concentration versus time curve, (AUC0-24) after 400 mg i.v. tds (AUC0-8 x 3) was equivalent to the AUC0-24 after 750 mg po bd (AUC0-12 x 2). Peak serum concentrations produced by the i.v. regimen were very similar to those observed after the 750 mg oral dose. The extent of accumulation was similar following either dosing regimen and was approximately 35%. Overall, the incidence of adverse effects (none of which was serious) was higher with the i.v. regimen than with the oral regimen, mainly due to injection site reaction, which was the most commonly reported adverse event.

Administration, Oral↗
PubMed1994

Safety and tolerance of intravenous nimodipine.

OBJECTIVE: To evaluate the safety and tolerance of intravenous nimodipine administered via a peripheral vein in healthy male volunteers. DESIGN: Double-blind, placebo- and vehicle-controlled trial with three fixed-dose panels. SETTING: Inpatient infusion and observation periods. SUBJECTS: 61 healthy male volunteers, aged 18-40 years. METHODS: Subjects in panel 1 received nimodipine 0.4 mg/h, vehicle 2 mL/h, or placebo 2 mL/h; subjects in panel 2 received nimodipine 1 mg/h, vehicle 5 mL/h, or placebo 5 mL/h; subjects in panel 3 received nimodipine 2 mg/h, vehicle 10 mL/h, or placebo 10 mL/h. All infusions were administered intravenously for 48 hours and volunteers were observed for 48 hours after cessation of the infusion. In addition to standard safety assessments (physical examination, electrocardiogram, laboratory studies, and adverse event reporting), supine and standing blood pressures and pulse rates were measured frequently. Plasma samples were also analyzed for nimodipine and its two demethylated metabolites. RESULTS: Of 61 subjects, 55 completed the 48-hour infusion and 6 discontinued the study because of adverse events. Intravenous nimodipine was well tolerated at 0.4 and 1 mg/h. However, all six subjects who received nimodipine 2 mg/h experienced moderate-to-severe adverse events, and one subject was discontinued because of dizziness, diaphoresis, and postural hypotension. The matched vehicle (10 mL/h) also was not well tolerated, with three subjects who discontinued because of phlebitis. Two subjects who received placebo were also discontinued during the study. Small (2 mm Hg) decreases in mean supine diastolic blood pressure were observed in the 0.4- and 1-mg/h nimodipine groups, but the 2-mg/h group showed a slight (5 mm Hg) increase in blood pressure. These changes were not clinically significant. Clearance and half-life of nimodipine and its metabolites were similar at all three dosages. CONCLUSIONS: Using peripheral vein administration, nimodipine 2 mg/h and matched vehicle at 10 mL/h were not well tolerated in this healthy normal population. The maximum tolerated dose of nimodipine was found to be 1 mg/h.

Adolescent↗
PubMed1993

Pharmacokinetics and serum bactericidal titers of ciprofloxacin and ofloxacin following multiple oral doses in healthy volunteers.

Fourteen adult males participated in a randomized three-way crossover study to compare the pharmacokinetics and serum bactericidal titers (SBTs) of 500 mg of ciprofloxacin (regimen A), 750 mg of ciprofloxacin (regimen B), and 400 mg of ofloxacin (regimen C) administered every 12 h for seven doses. Mean steady-state peak concentrations in serum for regimens A, B, and C were 3.0, 4.4, and 6.5 micrograms/ml, respectively (P < 0.01, all comparisons) and mean half-lives were 4.5, 4.3, and 6.5 h, respectively (P < 0.05, C versus A and B). Mean steady-state areas under the concentration-time curve were 14.1, 21.1, and 48.1 micrograms/h/ml for regimens A, B, and C, respectively (P < 0.05, all comparisons). SBTs were determined at different times postdose for three isolates each of Streptococcus pneumoniae, Staphylococcus aureus, Escherichia coli, Enterobacter cloacae, and Pseudomonas aeruginosa. Mean steady-state peak SBTs for regimens A, B, and C, respectively, were as follows: S. pneumoniae, < 1:2, 1:8, 1:8, S. aureus, 1:16, 1:16, 1:16; E. coli, 1: > or = 128, 1: > or = 128, 1:64; E. cloacae, 1: > or = 128, 1: > or = 128, 1:64; P. aeruginosa, 1:8, 1:8, 1:2. These differences in SBTs within each genus were statistically significant. The majority of predicted SBTs were within one dilution of measured SBTs. Areas under the serum bactericidal time curves for E. coli, E. cloacae, and P. aeruginosa were significantly higher for ciprofloxacin; areas under the serum bactericidal time curves for S. pneumoniae and S. aureus were significantly greater for ofloxacin. Ofloxacin achieved higher concentrations in serum than ciprofloxacin, but differences in in vitro activity were a more important determinant of SBTs.

Administration, Oral↗
PubMed1992

Effect of high doses of intravenously administered immune globulin on natural killer cell activity in peripheral blood.

Because Kawasaki disease is a disorder characterized by lymphocyte activation and immune complex destruction of endothelial cells, we examined the effect of administration of high doses of intravenously administered immune globulin (IVIG) on a lymphocyte population with affinity for endothelial cells: the natural killer cells. We found that administration of high doses of IVIG resulted in a significant increase in the activity of natural killer cells and in the numbers of circulating CD16+ cells. Furthermore, a study of patients treated with IVIG for seizure disorders suggests that this effect of IVIG on circulating NK cells is not unique to patients with Kawasaki disease. The beneficial effect of IVIG in the treatment of Kawasaki disease may be due to the ability of IVIG to inhibit interaction between natural killer cells and endothelial cells.

Antibody-Dependent Cell Cytotoxicity↗