Multiple-dose pharmacokinetics of concurrent oral ciprofloxacin and rifampin therapy in elderly patients

Ciprofloxacin population pharmacokinetics during long-term treatment of osteoarticular infections

BACKGROUND

Ciprofloxacin is an antibiotic used in osteoarticular infections owing to its very good bone penetration. Very few pharmacokinetic data are available in this population.

OBJECTIVES

To investigate oral ciprofloxacin population pharmacokinetics in adult patients treated for osteoarticular infections and propose guidance for more effective dosing.

METHODS

A retrospective population-pharmacokinetic analysis was performed on 92 consecutive hospitalized patients in the orthopaedic department. Ciprofloxacin plasma samples were obtained on one or two occasions during treatment. Plasma concentration was measured using ultra-performance liquid chromatography system coupled with tandem mass spectrometry. Data analysis was performed using a non-linear mixed-effect approach via Monolix 2019R2.

RESULTS

A total of 397 plasma samples were obtained with 11.5% and 41.6% of patients being below the therapeutic target for Gram-negative and staphylococcal infections, respectively. Ciprofloxacin pharmacokinetics were best described by a two-compartment model with a first-order absorption. Ciprofloxacin apparent plasma clearances and volumes of distribution were dependent on patients' fat-free mass according to the allometric rule. Elimination clearance was also positively related to renal function through the modification of diet in renal disease equation (MDRD) and rifampicin co-administration. When patients are co-treated with rifampicin, ciprofloxacin dosage should be increased by 50% to 60%.

CONCLUSIONS

This study showed that free-fat mass was a better size predictor than total body weight for ciprofloxacin clearance and volumes terms. Moreover, both MDRD and rifampicin status were significant predictors of individual ciprofloxacin clearance. Our study suggests that individual adjustment of ciprofloxacin dose in osteoarticular infections with less-susceptible bacteria might be indicated to reach required efficacy targets.

A Physiologically-Based Pharmacokinetic Model to Describe Ciprofloxacin Pharmacokinetics Over the Entire Span of Life

Background

Physiologically-based pharmacokinetic (PBPK) modeling has received growing interest as a useful tool for the assessment of drug pharmacokinetics by continuous knowledge integration.

Objective

The objective of this study was to build a ciprofloxacin PBPK model for intravenous and oral dosing based on a comprehensive literature review, and evaluate the predictive performance towards pediatric and geriatric patients.

Methods

The aim of this report was to establish confidence in simulations of the ciprofloxacin PBPK model along the development process to facilitate reliable predictions outside of the tested adult age range towards the extremes of ages. Therefore, mean data of 69 published clinical trials were identified and integrated into the model building, simulation and verification process. The predictive performance on both ends of the age scale was assessed using individual data of 258 subjects observed in own clinical trials.

Results

Ciprofloxacin model verification demonstrated no concentration-related bias and accurate simulations for the adult age range, with only 4.8% of the mean observed data points for intravenous administration and 12.1% for oral administration being outside the simulated twofold range. Predictions towards the extremes of ages for the area under the plasma concentration–time curve (AUC) and the maximum plasma concentration (C_max) over the entire span of life revealed a reliable estimation, with only two pediatric AUC observations outside the 90% prediction interval.

Conclusion

Overall, this ciprofloxacin PBPK modeling approach demonstrated the predictive power of a thoroughly informed middle-out approach towards age groups of interest to potentially support the decision-making process.

Electronic supplementary material

The online version of this article (10.1007/s40262-018-0661-6) contains supplementary material, which is available to authorized users.

Compositional dynamics of the human intestinal microbiota with aging: implications for health

The human gut contains trillions of microbes which form an essential part of the complex ecosystem of the host. This microbiota is relatively stable throughout adult life, but may fluctuate over time with aging and disease. The gut microbiota serves a number of functions including roles in energy provision, nutrition and also in the maintenance of host health such as protection against pathogens. This review summarizes the age-related changes in the microbiota of the gastrointestinal tract (GIT) and the link between the gut microbiota in health and disease. Understanding the composition and function of the gut microbiota along with the changes it undergoes overtime should aid the design of novel therapeutic strategies to counteract such alterations. These strategies include probiotic and prebiotic preparations as well as targeted nutrients, designed to enrich the gut microbiota of the aging population.

Compositional dynamics of the human intestinal microbiota with aging: implications for health

The human gut contains trillions of microbes which form an essential part of the complex ecosystem of the host. This microbiota is relatively stable throughout adult life, but may fluctuate over time with aging and disease. The gut microbiota serves a number of functions including roles in energy provision, nutrition and also in the maintenance of host health such as protection against pathogens. This review summarizes the age-related changes in the microbiota of the gastrointestinal tract (GIT) and the link between the gut microbiota in health and disease. Understanding the composition and function of the gut microbiota along with the changes it undergoes overtime should aid the design of novel therapeutic strategies to counteract such alterations. These strategies include probiotic and prebiotic preparations as well as targeted nutrients, designed to enrich the gut microbiota of the aging population.

Modeling, prediction, and in vitro in vivo correlation of CYP3A4 induction

CYP3A4 induction is not generally considered to be a concern for safety; however, serious therapeutic failures can occur with drugs whose exposure is lower as a result of more rapid metabolic clearance due to induction. Despite the potential therapeutic consequences of induction, little progress has been made in quantitative predictions of CYP3A4 induction-mediated drug-drug interactions (DDIs) from in vitro data. In the present study, predictive models have been developed to facilitate extrapolation of CYP3A4 induction measured in vitro to human clinical DDIs. The following parameters were incorporated into the DDI predictions: 1) EC(50) and E(max) of CYP3A4 induction in primary hepatocytes; 2) fractions unbound of the inducers in human plasma (f(u, p)) and hepatocytes (f(u, hept)); 3) relevant clinical in vivo concentrations of the inducers ([Ind](max, ss)); and 4) fractions of the victim drugs cleared by CYP3A4 (f(m, CYP3A4)). The values for [Ind](max, ss) and f(m, CYP3A4) were obtained from clinical reports of CYP3A4 induction and inhibition, respectively. Exposure differences of the affected drugs in the presence and absence of the six individual inducers (bosentan, carbamazepine, dexamethasone, efavirenz, phenobarbital, and rifampicin) were predicted from the in vitro data and then correlated with those reported clinically (n = 103). The best correlation was observed (R(2) = 0.624 and 0.578 from two hepatocyte donors) when f(u, p) and f(u, hept) were included in the predictions. Factors that could cause over- or underpredictions (potential outliers) of the DDIs were also analyzed. Collectively, these predictive models could add value to the assessment of risks associated with CYP3A4 induction-based DDIs by enabling their determination in the early stages of drug development.

Oral rifampin for eradication of Staphylococcus aureus carriage from healthy and sick populations: a systematic review of the evidence from comparative trials

BACKGROUND

Rifampin has been used for the eradication of Staphylococcus aureus (S. aureus) colonization in various populations of healthy and sick people.

METHODS

We performed a systematic review of the evidence from randomized and nonrandomized controlled trials that compared the effectiveness and safety of a rifampin-based regimen with another regimen in eradicating S. aureus colonization from healthy and sick people.

RESULTS

Nine comparative trials (6 of which were randomized controlled trials) were included in our analysis. S. aureus was eradicated more commonly in patients receiving rifampin-containing regimens compared to monotherapy with other systemic agents (ciprofloxacin, cloxacillin, minocycline, or vancomycin), both during early and late (>1 month after therapy) post treatment evaluations (odds ratio [OR] 46.2, 95% confidence interval [CI] 14.4-148, and OR 8.8, 95% CI 3.4-22.5 respectively, 4 studies included). There was no statistically significant difference between rifampin monotherapy and combinations of rifampin with other topical (bacitracin) or systemic (cloxacillin and minocycline) antibiotics in eradicating S. aureus both in early and late evaluations (OR 1.5, 95% CI 0.5-4.4, and OR 1.6, 95% CI 0.7-3.7, respectively, 3 studies included). Eradication of methicillin-resistant S. aureus (MRSA) varied according to the type and duration of the rifampin-containing regimen. It ranged from 25% for the combination of rifampin with trimethoprim/sulfamethoxazole for 5 days to 100% for the combination of oral rifampin and minocycline for 14 days. Discontinuation of rifampin due to drug-related toxicity was necessary in 2% of 282 studied patients. Development of resistance of S. aureus to rifampin during and after treatment with a regimen containing rifampin ranged from 0% to 40% (7 studies) and overall 17% of the 236 patients for whom relevant data was reported.

CONCLUSION

The available evidence suggests that oral rifampin is an effective agent for the eradication of S. aureus carriage. However, development of antimicrobial resistance during and after treatment with rifampin occurs in a considerable proportion of patients; using rifampin in combination with another antimicrobial agent may decrease this resistance.

Oral rifampin for prevention of S. aureus carriage-related infections in patients with renal failure--a meta-analysis of randomized controlled trials

BACKGROUND

Rifampin has been studied as prophylaxis against Staphylococcus aureus-related infections in patients on dialysis.

METHODS

We performed a meta-analysis of randomized controlled trials (RCTs) that compared the effectiveness and safety of oral rifampin with another regimen or no therapy in reducing S. aureus-related infections in dialysis patients.

RESULTS

Four RCTs evaluated oral rifampin (administered for 5 days every 3 months, or for 5 days once) as prophylaxis in dialysis patients. Oral rifampin with or without bacitracin was associated with less access-site infections with S. aureus compared with no treatment (odds ratio = 0.16, 95% confidence intervals: 0.06-0.44, 3 RCTs). There was no difference between prophylaxis with oral rifampin and topical mupirocin applied at the catheter site, for all studied outcomes, in the RCT comparing these regimens. Withdrawal from the study due to drug-related toxicity occurred in 7/107 (6.6%) of the studied patients with renal failure. Development of resistance of S. aureus to rifampin ranged from 0 to 18.2% (reported in three out of four included RCTs).

CONCLUSION

Prophylactic use of oral rifampin reduces access-site infections with S. aureus in patients with renal failure undergoing dialysis. However, development of toxicity and antimicrobial resistance during the treatment with rifampin occur in considerable proportions of patients, limiting its use and supporting the guidelines that recommend the use of local antibiotics at the exit site, such as mupirocin, for these indications. The available data are rather limited and more studies should be performed to examine this important clinical question.

Pharmacokinetic interactions with rifampicin : clinical relevance

The antituberculosis drug rifampicin (rifampin) induces a number of drug-metabolising enzymes, having the greatest effects on the expression of cytochrome P450 (CYP) 3A4 in the liver and in the small intestine. In addition, rifampicin induces some drug transporter proteins, such as intestinal and hepatic P-glycoprotein. Full induction of drug-metabolising enzymes is reached in about 1 week after starting rifampicin treatment and the induction dissipates in roughly 2 weeks after discontinuing rifampicin. Rifampicin has its greatest effects on the pharmacokinetics of orally administered drugs that are metabolised by CYP3A4 and/or are transported by P-glycoprotein. Thus, for example, oral midazolam, triazolam, simvastatin, verapamil and most dihydropyridine calcium channel antagonists are ineffective during rifampicin treatment. The plasma concentrations of several anti-infectives, such as the antimycotics itraconazole and ketoconazole and the HIV protease inhibitors indinavir, nelfinavir and saquinavir, are also greatly reduced by rifampicin. The use of rifampicin with these HIV protease inhibitors is contraindicated to avoid treatment failures. Rifampicin can cause acute transplant rejection in patients treated with immunosuppressive drugs, such as cyclosporin. In addition, rifampicin reduces the plasma concentrations of methadone, leading to symptoms of opioid withdrawal in most patients. Rifampicin also induces CYP2C-mediated metabolism and thus reduces the plasma concentrations of, for example, the CYP2C9 substrate (S)-warfarin and the sulfonylurea antidiabetic drugs. In addition, rifampicin can reduce the plasma concentrations of drugs that are not metabolised (e.g. digoxin) by inducing drug transporters such as P-glycoprotein. Thus, the effects of rifampicin on drug metabolism and transport are broad and of established clinical significance. Potential drug interactions should be considered whenever beginning or discontinuing rifampicin treatment. It is particularly important to remember that the concentrations of many of the other drugs used by the patient will increase when rifampicin is discontinued as the induction starts to wear off.

Antimicrobial drugs for treating methicillin-resistant Staphylococcus aureus colonization

BACKGROUND

Eradication strategies for methicillin-resistant Staphylococcus aureus (MRSA) are variable. We sought to summarize the evidence for use of antimicrobial agents to eradicate MRSA.

OBJECTIVES

To describe the effects of topical and systemic antimicrobial agents on nasal and extra-nasal MRSA carriage, adverse events, and incidence of subsequent MRSA infections.

SEARCH STRATEGY

We searched the Cochrane Infectious Diseases Group's trials register (August 2003), the Cochrane Central Register of Controlled Trials (Issue 3, 2003), MEDLINE (1966 to 2003), EMBASE (1988 to 2003), handsearched relevant literature, and contacted MRSA experts and the manufacturer of mupirocin.

SELECTION CRITERIA

Randomized controlled trials of patients colonized with MRSA comparing topical or systemic antimicrobials to placebo or no treatment, and trials comparing various combinations of topical or systemic agents to no treatment, placebo, or to topical or systemic agents.

DATA COLLECTION AND ANALYSIS

Two reviewers independently applied inclusion criteria to potentially relevant trials, assessed trial methodological quality, and extracted data. Primary outcomes included eradication of MRSA, infection due to MRSA, and adverse events.

MAIN RESULTS

Six trials (384 participants) met the inclusion criteria. No difference in MRSA eradication was detected in four studies: one that compared mupirocin to placebo, two that compared one systemic agent to no treatment (fusidic acid in one and rifampin or minocycline in the other) and one that compared mupirocin to topical fusidic acid and oral trimethoprim-sulfamethoxazole, examining nasal MRSA eradication as an outcome. One study compared minocycline to rifampin, with rifampicin being more effective in relation to eradication of MRSA from all sites at day 30 (relative risk 0.16; 95% confidence intervals 0.02 to 1.00), but the difference at 90 days was not statistically significant (n = 18). Two studies (one testing novobiocin and rifampin, the other ciprofloxacin and rifampin, versus trimethoprim-sulfamethoxazole and rifampin) did not demonstrate a difference in eradication of MRSA at all sites (n = 94). Adverse events with systemic agents occurred in up to 20% of participants, however reporting was sporadic and denominators small. All trials reported development of resistance to antimicrobial agents used.

REVIEWER'S CONCLUSIONS

There is insufficient evidence to support use of topical or systemic antimicrobial therapy for eradicating nasal or extra-nasal MRSA. There is no demonstrated superiority of either topical or systemic therapy, or of combinations of these agents. Potentially serious adverse events and development of antimicrobial resistance can result from therapy.

Interaction between ciprofloxacin and rifampin

OBJECTIVE

To discuss the necessity of dose adjustment for ciprofloxacin or rifampin during their concurrent use.

DATA SOURCES

A MEDLINE search (1966-December 1998) was completed using key terms rifampin and fluoroquinolone. English-language journals were considered.

DATA SYNTHESIS

Studies in elderly patients after 14 days of therapy with oral ciprofloxacin and rifampin did not demonstrate significant differences in the pharmacokinetics of ciprofloxacin as compared with those in patients receiving ciprofloxacin alone. Similar results were found in intravenous drug abusers. In comparison to the pharmacokinetics of both ciprofloxacin and rifampin when given alone, the serum bactericidal activity of rifampin, when given with ciprofloxacin in healthy elderly volunteers, was reduced but still evident. Ciprofloxacin pharmacodynamics were not significantly altered. Serum bacterial titers of ciprofloxacin and pefloxacin increased twofold when given with rifampin, although their clinical significance is unknown.

RECOMMENDATION

No strong evidence of a significant interaction exists to support dose adjustment for ciprofloxacin or rifampin during their concurrent use.

Pharmacokinetics of drugs used in critically ill adults

Critically ill patients exhibit a range of organ dysfunctions and often require treatment with a variety of drugs including sedatives, analgesics, neuromuscular blockers, antimicrobials, inotropes and gastric acid suppressants. Understanding how organ dysfunction can alter the pharmacokinetics of drugs is a vital aspect of therapy in this patient group. Many drugs will need to be given intravenously because of gastrointestinal failure. For those occasions on which the oral route is possible, bioavailability may be altered by hypomotility, changes in gastrointestinal pH and enteral feeding. Hepatic and renal dysfunction are the primary determinants of drug clearance, and hence of steady-state drug concentrations, and of efficacy and toxicity in the individual patient. Oxidative metabolism is the main clearance mechanism for many drugs and there is increasing recognition of the importance of decreased activity of the hepatic cytochrome P450 system in critically ill patients. Renal failure is equally important with both filtration and secretion clearance mechanisms being required for the removal of parent drugs and their active metabolites. Changes in the steady-state volume of distribution are often secondary to renal failure and may lower the effective drug concentrations in the body. Failure of the central nervous system, muscle, the endothelial system and endocrine system may also affect the pharmacokinetics of specific drugs. Time-dependency of alterations in pharmacokinetic parameters is well documented for some drugs. Understanding the underlying pathophysiology in the critically ill and applying pharmacokinetic principles in selection of drug and dose regimen is, therefore, crucial to optimising the pharmacodynamic response and outcome.

Ciprofloxacin. A review of its pharmacological profile and therapeutic use in the elderly

Ciprofloxacin belongs to the fluoroquinolone class of antimicrobial agents which primarily inhibit bacterial DNA gyrase. It is effective after oral or intravenous administration, demonstrating potent antibacterial activity against most Gram-negative, and many Gram-positive bacteria. Although most bacterial strains have remained susceptible to the drug, low rates of resistance have been observed in some strains of Pseudomonas aeruginosa and enterococci and higher rates in methicillin-resistant Staphylococcus aureus. Ciprofloxacin attains concentrations in most tissues and body fluids sufficient to inhibit the majority of susceptible pathogens. Its pharmacokinetic profile in the elderly (> or = 65 years) is broadly similar to that reported in younger persons, although plasma concentrations are higher, and renal clearance is decreased in elderly persons. Ciprofloxacin is an effective treatment for those infections most common in elderly patients, including infections of the urinary tract, lower respiratory tract, skin and soft-tissues, and bone and joints, and is an effective agent for prophylaxis in transurethral surgery. Orally administered ciprofloxacin appeared to be at least as effective as alternative orally administered antimicrobial agents (trimethoprim, cotrimoxazole [trimethoprim/sulfamethoxazole], amoxicillin, amoxicillin/clavulanic acid) and also as effective as various parenteral agents (ceftriaxone, cefamandole, ceftazidime, cefotaxime) in a small number of comparative clinical trials. However, further studies are needed to clarify the comparative efficacy of ciprofloxacin with that of other oral and parenteral agents in the elderly. Initial trials have also indicated therapeutic efficacy of oral ciprofloxacin in malignant external otitis and bacterial prostatitis. Nevertheless, with its good tolerability profile and potent antimicrobial activity following oral administration, ciprofloxacin appears to offer a valuable alternative for treating various acute and chronic infections in elderly patients. Causative pathogens are frequently multiresistant in this patient group, and ciprofloxacin avoids or minimises the need for parenteral therapy.

Influence of rifampin on fleroxacin pharmacokinetics

Staphylococcus aureus infections have been successfully treated in animal models with the combination of fleroxacin and rifampin. We studied the influence of rifampin, a potent cytochrome P-450 inducer, on the pharmacokinetics and biotransformation of fleroxacin in 14 healthy young male volunteers. Subjects were given 400 mg of fleroxacin orally once a day for 3 days to reach steady state. After a wash-out period of 2 days, the same subjects received 600 mg of rifampin orally once daily for 7 days. On days 5 to 7 of rifampin treatment, 400 mg of fleroxacin was again administered once daily. Concentrations of fleroxacin as well as its two major urinary metabolites, N-demethyl- and N-oxide-fleroxacin, in plasma and urine were determined by reverse-phase high-performance liquid chromatography. The extent of hepatic enzyme induction by rifampin was confirmed by a significant increase of 6-beta-hydroxycortisol urinary output from 160.8 +/- 41.4 to 544.8 +/- 120.7 micrograms/4 h. There were no significant changes in the peak fleroxacin concentration in plasma (6.3 +/- 1.2 versus 6.2 +/- 1.9 mg/liter), time to maximum concentration of fleroxacin in plasma (1.1 +/- 0.9 versus 1.3 +/- 1.1 h), or renal clearance (58.3 +/- 16.4 versus 61.9 +/- 19.2 ml/min). The area under the curve AUC (71.4 +/- 15.8 versus 62.2 +/- 13.7 mg.h/liter) and the terminal half-life of fleroxacin (11.4 +/- 2.2 versus 9.2 +/- 1.1 h) decreased (P < 0.05), while the total plasma clearance increased from 97.7 +/- 21.6 to 112.3 +/- 25.8 ml/min (P < 0.01). Despite being statistically significant, this 15% increase in total plasma clearance does not appear to be clinically relevant. Metabolic clearance by N demethylation was increased ( 6.9 +/- 2.4 versus 12.5 +/- 3.2 ml/min; P < 0.01), whereas clearance by N oxidation did not change (5.8 +/- 1.1 versus 5.8 +/- 1.5 ml/min). Fleroxacin elimination was slightly increased (about 15%) through induction of metabolic clearance to N-demethyl-fleroxacin. Since fleroxacin levels remained above the MIC for 90% of the tested isolates of methicillin-susceptible S. aureus for at least 24 h, dose adjustment does not appear necessary, at least for short-term treatments.

Crossover assessment of serum bactericidal activity and pharmacokinetics of ciprofloxacin alone and in combination in healthy elderly volunteers

To better define the pharmacokinetics and serum bactericidal activity (SBA) of ciprofloxacin and other antimicrobial agents in the elderly, six healthy (greater than 65 years) volunteers with normal renal function were given ciprofloxacin alone orally, ciprofloxacin plus rifampin orally, ciprofloxacin plus clindamycin orally, rifampin alone orally (three volunteers), and, for comparison of SBA against gram-positive cocci, vancomycin intravenously. Mean peak ciprofloxacin concentrations and other pharmacokinetic parameters were not altered significantly by coadministration of either rifampin or clindamycin. Ciprofloxacin had somewhat greater SBA against the oxacillin-susceptible and oxacillin-resistant Staphylococcus aureus strains tested than did vancomycin, but rifampin was by far the most active single agent tested. The SBA of rifampin against S. aureus was modestly antagonized during combination therapy with ciprofloxacin, but substantial SBA still was present. The ciprofloxacin SBA against S. aureus was completely antagonized by clindamycin if the strains were susceptible to the latter agent. Ciprofloxacin had modest SBA against group A streptococci and no SBA against the three pneumococcal strains tested. All of the regimens had poor to absent SBA against Enterococcus faecalis. By contrast, ciprofloxacin had excellent SBA against Escherchia coli and Klebsiella pneumoniae and moderate SBA against Pseudomonas aeruginosa. Combination therapy with rifampin or clindamycin in general enhanced the SBA against the nonenterococcal streptococci and had no effect on the SBA against the gram-negative bacilli.

Quinolone disposition in the elderly. Practical implications

The fluoroquinolones are antibiotics frequently used in infections that affect elderly individuals. The physiological aging process can profoundly affect the pharmacokinetics of drugs, necessitating adjustment of dosage regimens in the elderly. Changes in pharmacokinetics with age are mainly due to the progressive deterioration of renal function, with resultant lower clearance of drugs which are eliminated by the kidneys. Ofloxacin is almost totally renally excreted and elimination is slower in older age groups; a dose reduction is therefore recommended for this quinolone. Unexpected alterations in pharmacokinetics may occur, as exemplified by the increased bioavailability of oral ciprofloxacin in elderly subjects. This is a well-documented phenomenon of such significance that lower oral doses are advisable for the elderly. Renal clearance of ciprofloxacin decreases in old age, but because of substantial nonrenal elimination the total clearance is affected less. Studies of the pharmacokinetics of the other quinolones in old age are scarce. No data exist on the absolute oral bioavailability of norfloxacin, enoxacin and pefloxacin. Renal clearance seems to be reduced, but since no intravenous studies have been reported, the total and nonrenal clearances are unknown in the elderly. No safe conclusions can be drawn regarding the necessity of dose reductions from a pharmacokinetic point of view. However, reports of adverse reactions to quinolones in the elderly, especially concentration-dependent symptoms from the central nervous system, and the risk of interaction with other drugs, suggest the need for caution in determining dosages of all of these compounds in elderly subjects.