Effect of an antacid containing magnesium and aluminum on absorption, metabolism, and mechanism of renal elimination of pefloxacin in humans

Together or Apart? Revealing the Impact of Dietary Interventions on Bioavailability of Quinolones: A Systematic Review with Meta-analyses

BACKGROUND AND OBJECTIVE

Managing drug-food interactions is essential for optimizing the effectiveness and safety profile of quinolones. Following PRISMA guidelines, we systematically reviewed the influence of dietary interventions on the bioavailability of 22 quinolones.

METHODS

All studies describing or investigating the impact of food, beverages, antacids, and mineral supplements on pharmacokinetic parameters or pharmacokinetic/pharmacodynamic indices of orally taken quinolones were considered for inclusion. We excluded reviews, in vitro and in silico studies, studies performed on animals, and those involving alcohol. We performed the search in Medline (via PubMed), Embase, and Cochrane Library, covering reports from database inception to December 2022. We used the following tools to assess the risk of bias: version 2 of the Cochrane risk-of-bias tool for parallel trials, the Cochrane risk-of-bias tool for cross-over studies, and the NIH quality assessment tool for before-after studies. We performed quantitative analyses for each quinolone if two or more food-effect studies with specified and comparable study designs were available. If meta-analyses were not applicable, we qualitatively summarized the results.

RESULTS

We included 109 studies from 101 reports. Meta-analyses were conducted for 12 antibiotics and qualitative synthesis was employed for the remaining drugs. Of the studies, 60.5% were open-label, cross-over, as recommended by FDA. We judged 46% of studies as having a high risk of bias and only 4% of having a low risk of bias. Among 19 quinolones with available food impact data, 14 (74%) had potentially clinically important interactions. For nalidixic acid, oxolinic acid, and tosufloxacin, food exerted a high positive impact on bioavailability (AUC or Cmax increased by > 45%), whereas, for all the remaining drugs, postprandial absorption was lower. The most significant negative influence of food (AUC or Cmax decreased by > 40%) occurred for delafloxacin capsules and norfloxacin, whereas the moderate influence (AUC or Cmax decreased by 30-40%) occurred for nemonoxacin and rufloxacin. All 14 analysed quinolones showed a substantial reduction in bioavailability when co-administered with antacids and mineral supplements, except for calcium preparations. The impact of beverages was evaluated for 10 quinolones, with 50% experiencing significantly reduced absorption in the presence of milk (the highest negative impact for ciprofloxacin). Moreover, both ciprofloxacin and levofloxacin demonstrated compromised bioavailability when consumed with orange juice, particularly calcium-fortified.

DISCUSSION

Several factors may influence interactions, including the physicochemical characteristics of quinolones, the type of intervention, drug formulation, and the patient's health status. We assessed the quality of evidence as low due to the poor actuality of included studies, their methodological diversity, and uneven data availability for individual drugs.

Effects of Magnesium, Calcium, and Aluminum Chelation on Fluoroquinolone Absorption Rate and Bioavailability: A Computational Study

Fluoroquinolones (FQs) are a widespread class of broad-spectrum antibiotics prescribed as a first line of defense, and, in some cases, as the only treatment against bacterial infection. However, when administered orally, reduced absorption and bioavailability can occur due to chelation in the gastrointestinal tract (GIT) with multivalent metal cations acquired from diet, coadministered compounds (sucralfate, didanosine), or drug formulation. Predicting the extent to which this interaction reduces in vivo antibiotic absorption and systemic exposure remains desirable yet challenging. In this study, we focus on quinolone interactions with magnesium, calcium and aluminum as found in dietary supplements, antacids (Maalox) orally administered therapies (sucralfate, didanosine). The effect of FQ-metal complexation on absorption rate was investigated through a combined molecular and pharmacokinetic (PK) modeling study. Quantum mechanical calculations elucidated FQ-metal binding energies, which were leveraged to predict the magnitude of reduced bioavailability via a quantitative structure-property relationship (QSPR). This work will help inform clinical FQ formulation design, alert to possible dietary effects, and shed light on drug-drug interactions resulting from coadministration at an earlier stage in the drug development pipeline.

Comparable Bioavailability and Disposition of Pefloxacin in Patients with Cystic Fibrosis and Healthy Volunteers Assessed via Population Pharmacokinetics

Quinolone antibiotics present an attractive oral treatment option in patients with cystic fibrosis (CF). Prior studies have reported comparable clearances and volumes of distribution in patients with CF and healthy volunteers for primarily renally cleared quinolones. We aimed to provide the first pharmacokinetic comparison for pefloxacin as a predominantly nonrenally cleared quinolone and its two metabolites between both subject groups. Eight patients with CF (fat-free mass [FFM]: 36.3 ± 6.9 kg, average ± SD) and ten healthy volunteers (FFM: 51.7 ± 9.9 kg) received 400 mg pefloxacin as a 30 min intravenous infusion and orally in a randomized, two-way crossover study. All plasma and urine data were simultaneously modelled. Bioavailability was complete in both subject groups. Pefloxacin excretion into urine was approximately 74% higher in patients with CF compared to that in healthy volunteers, whereas the urinary excretion of metabolites was only slightly higher in patients with CF. After accounting for body size and composition via allometric scaling by FFM, pharmacokinetic parameter estimates in patients with CF divided by those in healthy volunteers were 0.912 for total clearance, 0.861 for nonrenal clearance, 1.53 for renal clearance, and 0.916 for volume of distribution. Nonrenal clearance accounted for approximately 90% of total pefloxacin clearance. Overall, bioavailability and disposition were comparable between both subject groups.

The effect of staggered administration of zinc sulfate on the pharmacokinetics of oral cephalexin

AIMS

To investigate the effect of zinc sulfate on pharmacokinetics of cephalexin when administered concurrently or at strategically spaced dosing times designed to avoid the potential interaction in healthy volunteers.

METHODS

In this study, all subjects (n= 12) were randomized to receive the following four treatments, separated by a wash-out period of 7 days: cephalexin 500mg alone, concomitantly with zinc 250mg, 3h after zinc 250mg or 3h before zinc 250mg.

RESULTS

All subjects completed the study safely. Zinc supplements administered concurrently with cephalexin significantly decreased the peak serum concentration (C(max) ), area under the plasma concentration-time curve from zero to infinity (AUC(0-∞) ) and the time for which the plasma concentration of the drug remained above the minimal inhibitory concentration of the pathogenic organism (T > MIC) of cephalexin [mean percentage decrease (95% confidence intervals) of 31.05% (22.09-40.01%), 27.40% (18.33-36.47%) and 22.33% (12.51-32.16%), respectively; P < 0.05] compared with administration of cephalexin alone. Also, administration of zinc 3h before cephalexin decreased the C(max) , AUC(0-∞) and T > MIC of the drug compared with administration of cephalexin alone [mean percentage decrease (95% confidence intervals) of 11.48% (3.40-19.55%), 18.12% (9.63-26.60%) and 23.75% (14.30-33.20%), respectively; P < 0.05]. In contrast, the pharmacokinetics of cephalexin was not notably altered by administration of zinc 3h after cephalexin dosing (P > 0.05).

CONCLUSIONS

The significant interaction between zinc and cephalexin might affect the clinical outcome of cephalexin therapy. The dosing recommendation is that zinc sulfate can be safely administered 3h after a cephalexin dose.

Clinically significant drug interactions with antacids: an update

One may consider that drug-drug interactions (DDIs) associated with antacids is an obsolete topic because they are prescribed less frequently by medical professionals due to the advent of drugs that more effectively suppress gastric acidity (i.e. histamine H(2)-receptor antagonists [H2RAs] and proton pump inhibitors [PPIs]). Nevertheless, the use of antacids by ambulant patients may be ever increasing, because they are freely available as over-the-counter (OTC) drugs. Antacids consisting of weak basic substances coupled with polyvalent cations may alter the rate and/or the extent of absorption of concomitantly administered drugs via different mechanisms. Polyvalent cations in antacid formulations may form insoluble chelate complexes with drugs and substantially reduce their bioavailability. Clinical studies demonstrated that two classes of antibacterials (tetracyclines and fluoroquinolones) are susceptible to clinically relevant DDIs with antacids through this mechanism. Countermeasures against this type of DDI include spacing out the dosing interval - taking antacid either 4 hours before or 2 hours after administration of these antibacterials. Bisphosphonates may be susceptible to DDIs with antacids by the same mechanism, as described in the prescription information of most bisphosphonates, but no quantitative data about the DDIs are available. For drugs with solubility critically dependent on pH, neutralization of gastric fluid by antacids may alter the dissolution of these drugs and the rate and/or extent of their absorption. However, the magnitude of DDIs elicited by antacids through this mechanism is less than that produced by H2RAs or PPIs; therefore, the clinical relevance of such DDIs is often obscure. Magnesium ions contained in some antacid formulas may increase gastric emptying, thereby accelerating the rate of absorption of some drugs. However, the clinical relevance of this is unclear in most cases because the difference in plasma drug concentration observed after dosing shortly disappears. Recent reports have indicated that some of the molecular-targeting agents such as the tyrosine kinase inhibitors dasatinib and imatinib, and the thrombopoietin receptor agonist eltrombopag may be susceptible to DDIs with antacids. Finally, the recent trend of developing OTC drugs as combination formulations of an antacid and an H2RA is a concern because these drugs will increase the risk of DDIs by dual mechanisms, i.e. a gastric pH-dependent mechanism by H2RAs and a cation-mediated chelation mechanism by antacids.

Effect of calcium supplements on the oral bioavailability of moxifloxacin in healthy male volunteers

OBJECTIVE

To investigate the effect of concomitant calcium administration on the pharmacokinetics and tolerability of moxifloxacin.

DESIGN

This was a nonblinded, randomised, single dose, crossover study in healthy male volunteers.

PARTICIPANTS

12 healthy male Caucasians (age 24 to 45 years) were enrolled in the study.

METHODS

In each of the 2 study periods, each volunteer received a single oral morning dose of moxifloxacin 400mg after an overnight fast. In 1 of the study periods, Ca2+ 500mg (Calcium-Sandoz Forte) was administered immediately before, and 12 and 24 hours after, moxifloxacin (total of 3 doses of Ca2+). The 2 study periods were separated by a washout period of at least 2 weeks.

RESULTS

Moxifloxacin was well tolerated throughout the study. There was no difference in the area under the plasma concentration-time curve from zero to infinity [AUCinfinity; geometric mean (SD)] of moxifloxacin [32.2 (1.24) vs 33.0 (1.26) mg/L x h, with vs without Ca2+]. Maximum plasma concentration (Cmax) [2.29 (1.27) vs 2.71 (1.33) mg/L, with vs without Ca2+] slightly decreased by approximately 16% and the time to Cmax [median (range)] tended to be slightly prolonged [2.5 (0.8 to 3) vs 0.9 (0.5 to 2.5) hours, with vs without Ca2+].

CONCLUSIONS

The extent of absorption of moxifloxacin is not affected by concomitant Ca2+ intake, whereas the rate of absorption is slightly reduced, an effect not considered to be of clinical relevance. Hence, moxifloxacin may be administered together with Ca2+ without dosage adjustments or special recommendations.

Evaluation of the influence of antacids and H2 antagonists on the absorption of moxifloxacin after oral administration of a 400mg dose to healthy volunteers

OBJECTIVE

To determine the effect of concomitant administration of the antacid Maalox 70 or the histamine H2 receptor antagonist ranitidine on the bioavailability of moxifloxacin.

DESIGN

These were nonblinded, randomised, crossover studies performed in healthy volunteers.

PARTICIPANTS

24 healthy males aged 22 to 39 years (study 1; n = 12) and 24 to 43 years (study 2; n = 12) were included in these studies.

METHODS

In study 1, 12 participants received ranitidine 150mg twice daily during a 3-day pretreatment phase and 1 tablet of ranitidine together with a single 400mg dose of moxifloxacin on the profile day. In study 2, 12 participants received a single 400mg dose of moxifloxacin alone (treatment A), simultaneously with Maalox 70 10ml (treatment B), or with Maalox 70 10ml given 4 hours before (treatment C) or 2 hours after (treatment D) the fluoroquinolone. In treatments B, C and D, administration of the antacid (10ml, 1 hour after each meal) was continued for 2 days. Plasma and urine samples were obtained for determination of the pharmacokinetic parameters of moxifloxacin.

RESULTS

Coadministration of moxifloxacin with ranitidine showed lack of interaction for area under the plasma concentration-time curve extrapolated to infinity (AUCinfinity) [35.5 versus 34.3 mg/L x h with versus without ranitidine; relative bioavailability 103%, 90% confidence interval (CI) 97.7 to 109.3%] and maximum plasma concentration (Cmax) [2.98 versus 2.76 mg/L with versus without ranitidine; ratio 107.9%, 90% CI 90.5 to 128.6%]. When moxifloxacin was given simultaneously with Maalox 70, AUCinfinity ( 14.7 mg/L x h) and Cmax (1.00 mg/L) were reduced by approximately 60%. When the antacid was given 4 hours before or 2 hours after the fluoroquinolone, AUCinfinity values (28.0 and 26.7 versus 34.3 mg/L x h) were moderately reduced (by <27%), terminal elimination half-life values declined by approximately 24% (9.4 and 9.3 versus 12.3 hours) compared with moxifloxacin alone and Cmax values were almost unchanged (2.55 and 2.38 versus 2.57 mg/L). The mean bioavailabilities corrected for the elimination rate constants (lambdaz) were 101% (antacid given 4 hours before moxifloxacin) and 98% (antacid given 2 hours after moxifloxacin), indicating that Maalox 70 may interfere with the gastrointestinal recirculation of moxifloxacin.

CONCLUSIONS

The bioavailability of moxifloxacin is not affected by concurrent administration of ranitidine. Absorption of moxifloxacin is impaired by concomitant administration of aluminium- and magnesium-containing antacids and administration of these agents should be staggered. An interval of 2 hours before or 4 hours after taking the antacid ensures that the effect of the interaction is not clinically relevant.

Selection of drugs to treat gastro-oesophageal reflux disease: the role of drug interactions

Gastro-oesophageal reflux disease is probably the most common acid-peptic disease in Western countries, and the successful treatment of mild to moderate disease with pharmacotherapy has become commonplace. A large number of effective drugs are now available, and so the decision-making process for physicians increasingly relies on considerations other than pure efficacy. Cost, adverse effects and drug interactions have therefore become important, particularly in the most vulnerable patients - children, the elderly and patients who are ill and are taking medications that may influence the efficacy of antireflux therapy. Important drug interactions with antacids include the prevention of the absorption of antibacterials such as tetracycline, azithromycin and quinolones. H2 antagonists, proton pump inhibitors and prokinetic agents undergo metabolism by the cytochrome P450 (CYP) system present in the liver and gastrointestinal tract. Cimetidine is an inhibitor of CYP3A and it may cause significant interactions with drugs of narrow therapeutic range and low bioavailability that are metabolised by these enzymes. The gastroparietal proton pump inhibitors lansoprazole, omeprazole and pantoprazole are all primarily metabolised by a genetically polymorphic enzyme, CYP2C19, that is absent from approximately 3% of Caucasians and 20% of Asians. These drugs may also interact with CYP3A, but to a lesser extent. Interactions with prokinetic agents carry the greatest potential for harm. Metoclopramide is a dopamine antagonist that may cause extrapyramidal effects when administered alone at high concentrations, or when coadministered with antipsychotic agents such as haloperidol or phenothiazines. Cisapride is clearly able to prolong the electrocardiographic QT interval and cause lethal ventricular arrhythmias when its metabolism is slowed by interaction with inhibitors of CYP3A, such as erythromycin, ketoconazole or itraconazole.

Pharmacokinetics and pharmacodynamics of fluoroquinolones

The fluoroquinolones have moderate to excellent bioavailability, moderate to long elimination half-lives (50 to 98%) and volumes of distribution >1.5 L/kg. There is considerable variation in elimination pattern between fluoroquinolone agents, ranging from predominant renal excretion to extensive hepatic metabolism. Protein binding also varies between agents. Tissue concentrations often exceed plasma concentrations, while concentrations in CSF are modest in the presence of inflammation. Fluoroquinolones show concentration-dependent killing in vitro, and animal models have demonstrated the 24-hour AUC/MIC (area under the concentration-time curve/minimum inhibitory concentration) ratio to be the best predictor of bacterial killing in vivo, with the peak plasma concentration (Cmax)/MIC ratio being important for some bacteria, to prevent the emergence of resistance during treatment. Animal models and human studies with ciprofloxacin, grepafloxacin and levofloxacin show that a 24-hour AUC/MIC ratio of about 100, or a Cmax/MIC ratio of about 10 gives maximum clinical and bacteriological efficacy. These values can be used to predict the efficacy of different agents against different pathogens, and to define pharmacodynamic 'breakpoints'.

Absorption interactions with fluoroquinolones. 1995 update

The utility of the fluoroquinolone class of antibiotics is rapidly expanding due to their favourable pharmacokinetic profile and the continuing development of new compounds. These agents are often used for indications not successfully treated with other orally available antimicrobials in the past, or for 'step-down' therapy in patients originally treated with intravenous agents. As the usage of these agents expands for serious systemic infections, knowledge of absorptive interactions with fluoroquinolones becomes paramount. Fluoroquinolones are often utilised in dosages and against modestly susceptible pathogens which allow a narrow margin for acceptable decreases in bioavailability. Chelation interactions with multivalent cations can result in inactivation of the fluoroquinolone with ramifications in vitro and in vivo. Chelation interactions have been reported to occur in between 22 and 76% of patients prescribed fluoroquinolones. Concurrent administration of magnesium-aluminum antacids and sucralfate has the greatest effect on the bioavailability of quinolones followed by iron, calcium and zinc. Spacing doses of fluoroquinolones and interactants has been suggested as a method of ensuring adequate quinolone absorption, but this can make optimal administration of the cation interactant difficult, if not impossible.