Crystalluria and ciprofloxacin, influence of urinary pH and hydration

Physical compatibility of sulbactam/durlobactam with select intravenous drugs during simulated Y-site administration

PURPOSE

Sulbactam/durlobactam is a combination antibiotic designed to target Acinetobacter baumannii, including carbapenem-resistant and multidrug-resistant strains. The objective of this study was to determine the physical compatibility of sulbactam/durlobactam solution during simulated Y-site administration with 95 intravenous (IV) drugs.

METHODS

Vials of sulbactam/durlobactam solution were diluted in 0.9% sodium chloride injection to a volume of 100 mL (the final concentration of both drugs was 15 mg/mL). All other IV drugs were reconstituted according to the manufacturer's recommendations and diluted with 0.9% sodium chloride injection to the upper range of concentrations used clinically or tested undiluted as intended for administration. Y-site conditions were simulated by mixing 5 mL of sulbactam/durlobactam with 5 mL of the tested drug solutions in a 1:1 ratio. Solutions were inspected for physical characteristics (clarity, color, and Tyndall effect), turbidity, and pH changes before admixture, immediately post admixture, and over 4 hours. Incompatibility was defined as any observed precipitation, significant color change, positive Tyndall test, or turbidity change of ≥0.5 nephelometric turbidity unit during the observation period.

RESULTS

Sulbactam/durlobactam was physically compatible with 38 out of 42 antimicrobials tested (90.5%) and compatible overall with 86 of 95 drugs tested (90.5%). Incompatibility was observed with albumin, amiodarone hydrochloride, ceftaroline fosamil, ciprofloxacin, daptomycin, levofloxacin, phenytoin sodium, vecuronium, and propofol.

CONCLUSION

The Y-site compatibility of sulbactam/durlobactam with 95 IV drugs was described. These compatibility data will assist pharmacists and nurses to safely coordinate administration of IV medications with sulbactam/durlobactam.

Pathophysiology of Acute Kidney Injury in Critical Illness: A Narrative Review

Acute kidney injury (AKI) is a syndrome that entails a rapid decline in kidney function with or without injury. The consequences of AKI among acutely ill patients are dire and lead to higher mortality, morbidity, and healthcare cost. To prevent AKI and its short and long-term repercussions, understanding its pathophysiology is essential. Depending on the baseline kidney histology and function reserves, the number of kidney insults, and the intensity of each insult, the clinical presentation of AKI may differ. While many factors are capable of inducing renal injury, they can be categorized into a few processes. The three primary processes reported in the literature are hemodynamic changes, inflammatory reactions, and nephrotoxicity. The majority of patients with AKI will suffer from more than one during their development and/or progression of AKI. Moreover, the development of one usually leads to the instigation of another. Thus, the interactions and progression between these mechanisms may determine the severity and duration of the AKI. Other factors such as organ crosstalk and how our concurrent therapies interact with these mechanisms complicate the pathophysiology of the progression of the AKI even further. In this narrative review article, we describe these three main pathophysiological processes that lead to the development and progression of AKI. © 2022 American Physiological Society. Compr Physiol 12: 1-14, 2022.

Rhabdomyolysis, myoglobinuric nephrosis, and crystalline nephropathy in a captive bottlenose dolphin

A 5-y-old female bottlenose dolphin (Tursiops truncatus) from an aquarium in Japan had clinical signs of anorexia, vomiting, and bradykinesia. Enrofloxacin and lactated Ringer solution were administered for treatment of bacterial infection and for rehydration. Elevations of creatine kinase and aspartate aminotransferase activities were detected on day 4 of treatment, indicating that rhabdomyolysis had developed on day 3. On day 5, serum creatinine and urea concentrations increased and remained high throughout the remaining treatment; the dolphin died on day 16. Postmortem examination revealed massive necrosis of the longissimus dorsi muscles. Histologic examination revealed extensive necrosis of skeletal myofibers, multifocal renal tubular necrosis with intratubular casts and crystals, and suppurative bronchopneumonia. The renal casts labeled positively with anti-myoglobin antibody; expression of aquaporin-1 was decreased in renal tubules compared to normal kidney tissue. To our knowledge, this description of clinicopathologic findings of rhabdomyolysis leading to acute kidney injury with concomitant crystalline nephropathy has not been reported previously in a bottlenose dolphin.

Alkalising agents in urinary tract infections: theoretical contraindications, interactions and synergy

Introduction:

Alkalising agents have the potential to enhance the efficacy of many antimicrobial agents used in the treatment of Urinary Tract Infections; they also have the potential to cause significant patient harm if used incorrectly. This work seeks to illustrate and quantify these risks and synergies by modelling drug solubility and supersaturation against pharmacokinetic data for commonly used antibiotic agents.

Methods:

Solubility-pH relationships are employed to quantify the crystalluria risk for compounds which may be reasonably expected to be co-prescribed—or co-administered—with urinary alkalisers (amoxicillin, nitrofurantoin, trimethoprim, sulfamethoxazole and ciprofloxacin). These results are correlated against reports of crystalluria in the literature and in the EU Adverse Drug Reaction database.

Results and Discussion:

We find a correlation between the maximum theoretical supersaturation attainable and crystalluria reports for sulfamethoxazole, amoxicillin and ciprofloxacin. Shifts in urine pH which can be induced by alkalising agents may produce supersaturated states (and thus induce crystalluria) and may also affect antimicrobial efficacy. The importance of employing biorelevant media to improve predictive capacity of this analysis is also discussed.

Conclusion:

Despite their widespread use, alkalising agents have significant effects on the pharmacokinetics of the most common drugs used to treat UTIs. With self-care set to increase, all OTC products should be critically re-evaluated to ensure patient safety, particularly within contexts where healthcare professionals are not involved in treatment selection. This analysis suggests a need for consistency across patient and healthcare professional documents to improve clarity.

Plain Language Summary

OTC Alkalising agents need additional warning information

The Crystalline Nephropathies

Crystalline nephropathies are a unique form of kidney disease characterized by the histologic finding of intrarenal crystal deposition. The intrinsic nature of some molecules and ions combined with a favorable tubular fluid physiology leads to crystal precipitation and deposition within the tubular lumens. Crystal deposition promotes kidney injury through tubular obstruction and both direct and indirect cytotoxicities. Further kidney injury develops from inflammation triggered by these crystals. From a clinical standpoint, the crystalline nephropathies are associated with abnormal urinalysis and urinary sediment findings, tubulopathies, acute kidney injury (AKI), and/or chronic kidney disease (CKD). Urine sediment examination is often helpful in alerting clinicians to the possibility of crystal-related kidney injury. The identification of crystals within the kidneys on biopsy by pathologists prompts clinicians to evaluate patients for medication-related kidney injury, dysproteinemia-related malignancies, and certain inherited disorders. This review will focus on the clinical and pathologic aspects of these 3 categories of crystalline nephropathies.

High-Throughput in vitro Gel-Based Plate Assay to Screen for Calcium Oxalate Stone Inhibitors

OBJECTIVE

Kidney stones are a common medical condition that is increasing in prevalence worldwide. Approximately, ∼80% of urinary calculi are composed of calcium oxalate (CaOx). There is a growing interest toward identifying therapeutic compounds that can inhibit the formation of CaOx crystals. However, some chemicals (e.g., antibiotics and bacterial metabolites) may directly promote crystallization. Current knowledge is limited regarding crystal promoters and inhibitors. Thus, we have developed an in vitro gel-based diffusion model to screen for substances that directly influence CaOx crystal formation.

MATERIALS AND METHODS

We used double diffusion of sodium oxalate and calcium chloride-loaded paper disks along an agar medium to facilitate the controlled formation of monohydrate and dihydrate CaOx crystals. A third disk was used for the perpendicular diffusion of a test substance to assess its influence on CaOx crystal formation.

RESULTS

We confirmed that citrates and magnesium are effective inhibitors of CaOx crystals. We also demonstrated that 2 strains of uropathogenic Escherichia coli are able to promote crystal formation. While the other tested uropathogens and most antibiotics did not change crystal formation, ampicillin was able to reduce crystallization.

CONCLUSION

We have developed an inexpensive and high-throughput model to evaluate substances that influence CaOx crystallization.

Nephrotoxicity of Antimicrobials and Antibiotics

Medication-induced nephrotoxicity remains one of the most common causes of acute kidney injury (AKI) among hospitalized patients. Within the extensive group of medications associated with AKI, antibiotics and other antimicrobials are well recognized triggers of structural and functional renal impairment. Clinical manifestations range from mild forms of tubular injury to significant deterioration of kidney function requiring acute renal replacement therapy. Several mechanisms are described, although the most frequent are acute interstitial nephritis, acute tubular necrosis, intratubular crystal deposition, and proximal/distal tubulopathy with electrolyte wasting abnormalities. General risk factors for antimicrobial-induced AKI include pre-existing chronic kidney disease, and concomitant use of medication with nephrotoxic potential. Prevention and early recognition of AKI represent the standard approach to mitigate AKI and avoid morbidity.

A Rare Case of Acute Kidney Injury Due to Levofloxacin-induced Crystal Nephropathy

Crystal-induced acute kidney injury (AKI) is caused by the intratubular precipitation of crystals, which results in obstruction and kidney injury. Levofloxacin is commonly used fluoroquinolone antibiotic especially for respiratory and urinary tract infections. It rarely causes any serious adverse events. Several cases of crystal nephropathy after ciprofloxacin use have been reported. Pre-existing renal dysfunction, high dose of the drug, and advanced age are considered as risk factors. To best of our knowledge, only two cases of crystal nephropathy due to levofloxacin use have been reported, we add a new one to it. The patient responded to conservative treatment with complete recovery on follow-up.

Crystalline Nephropathy in Renal Transplant: A Series of 4 Cases

Crystals are particles of endogenous inorganic or organic composition that can trigger kidney injury when deposited or formed inside the kidney. The most common forms of crystalline nephropathies (CNs) are nephrocalcinosis and oxalate nephropathy. The causes of early allograft dysfunction are changing constantly, and recently calcium oxalate (CaOx) crystal deposition has been added to this list. CaOx deposition in renal allograft is important and probably under-recognized cause of delayed graft function that requires adequate awareness with early intervention to improve the allograft outcome. Here, we describe four cases of irreversible renal graft injury due to CNs.

Nephrotoxicity of Ciprofloxacin: Five Cases and a Review of the Literature

Fluoroquinolones are usually well tolerated with a minimum of serious adverse effects; renal toxicity is uncommon. Apart from the renal side effects of ciprofloxacin, we aimed to highlight the renal impact of a ciprofloxacin overdose, and thus conducted a prospective study in the Department of Nephrology at La Rabta Hospital between 2010 and 2015. The cohort database was continually updated until the inclusion of five patients who were subjected to an overdose and who were initially admitted to the medical intensive care unit and then transferred to our department for acute renal failure (ARF) due to ciprofloxacin ingestion requiring urgent hemodialysis. All patients developed ARF after 12–36 h of ingestion. Renal ultrasound was normal in all cases. Twenty-four-hour proteinuria was present but not significant in one case, while microscopic hematuria was present in one case. Treatment consisted of supportive therapy and extrarenal purification by conventional intermittent hemodialysis. Four patients recovered normal renal function within 3 weeks and the remaining patient eventually had chronic kidney failure.

Drug-Induced Kidney Stones and Crystalline Nephropathy: Pathophysiology, Prevention and Treatment

Drug-induced calculi represent 1-2% of all renal calculi. The drugs reported to produce calculi may be divided into two groups. The first one includes poorly soluble drugs with high urine excretion that favour crystallisation in the urine. Among them, drugs used for the treatment of patients with human immunodeficiency, namely atazanavir and other protease inhibitors, and sulphadiazine used for the treatment of cerebral toxoplasmosis, are the most frequent causes. Besides these drugs, about 20 other molecules may induce nephrolithiasis, such as ceftriaxone or ephedrine-containing preparations in subjects receiving high doses or long-term treatment. Calculi analysis by physical methods including infrared spectroscopy or X-ray diffraction is needed to demonstrate the presence of the drug or its metabolites within the calculi. Some drugs may also provoke heavy intra-tubular crystal precipitation causing acute renal failure. Here, the identification of crystalluria or crystals within the kidney tissue in the case of renal biopsy is of major diagnostic value. The second group includes drugs that provoke the formation of urinary calculi as a consequence of their metabolic effects on urinary pH and/or the excretion of calcium, phosphate, oxalate, citrate, uric acid or other purines. Among such metabolically induced calculi are those formed in patients taking uncontrolled calcium/vitamin D supplements, or being treated with carbonic anhydrase inhibitors such as acetazolamide or topiramate. Here, diagnosis relies on a careful clinical inquiry to differentiate between common calculi and metabolically induced calculi, of which the incidence is probably underestimated. Specific patient-dependent risk factors also exist in relation to urine pH, volume of diuresis and other factors, thus providing a basis for preventive or curative measures against stone formation.

Acute Ciprofloxacin-Induced Crystal Nephropathy with Granulomatous Interstitial Nephritis

Crystal-induced acute kidney injury (AKI) is caused by the intratubular precipitation of crystals, which results in obstruction and kidney injury. Ciprofloxacin, a commonly used antibiotic, causes AKI secondary to immune-mediated interstitial injury. Rare mechanisms of ciprofloxacin-induced renal injury include crystalluria, rhabdomyolysis, and granulomatous interstitial nephritis. Clinical and experimental studies have suggested that crystalluria and crystal nephropathy due to ciprofloxacin occur in alkaline urine. Preexisting kidney function impairment, high dose of the medication, and advanced age predispose to this complication. We report a case of ciprofloxacin-induced crystal nephropathy and granulomatous interstitial nephritis in a young patient with no other predisposing factors. The patient responded to conservative treatment without the need for glucocorticoids.

Is ciprofloxacin safe in patients with solitary kidney and upper urinary tract infection?

The solitary kidney (SK) undergoes adaptive phenomena of hyperfunction and hyperfiltration. These secondary adaptive phenomena can make it more vulnerable to potentially nephrotoxic therapies. Adverse reactions of the kidneys to ciprofloxacin are rare, but sometimes severe. Therefore, our study sought to assess the reactions to ciprofloxacin of patients with solitary kidney (SK) and urinary tract infection (UTI) by means of urinary biomarkers. We studied 19 patients with SK and urinary tract infection (UTI) who had been administered a 7-day treatment with intravenous ciprofloxacin. Urinary N-acetyl-beta-d-glucosaminidase, alpha 1-microglobulin, and estimated glomerular filtration rate (eGFR) of these patients were measured at the initiation and at the end of treatment. In 47.37% patients NAG diminished under ciprofloxacin treatment. This observation has the significance of favourable evolution of the tubulointerstitial lesions caused by UTI and lack of nephrotoxic effects; 52.63% cases presented an increase of urinary NAG, a fact that suggests a nephrotoxic effect of ciprofloxacin. The evolution of urinary alpha 1-microglobulin was similar to that one of urinary NAG. Only one of three cases with chronic kidney disease (CKD) stage 5 presented acute kidney injury, associated with increase in the tubular markers. In spite of the high variability of the urinary biomarkers, UTI evolved favourably in these cases; eGFR increased in 16 out of 19 patients, a fact which is indicative of a good outcome of renal function, even in patients with elevated levels of the tubular damage biomarkers. This observation supports the hypothesis that eGFR may be dissociated from the biomarkers which assess tubular injury. In SK patients the occurrence of AKI is not frequent, although the urinary biomarkers rise in some patients treated with ciprofloxacin. This is related not only to the nephrotoxic effect of the drug, but probably to the association of other factors (allergy, individual susceptibility). In SK patients, renal tubular biomarkers, especially NAG, allow monitoring of tubular injury and impose caution in prescribing ciprofloxacin treatment, mainly to patients at risk. Ciprofloxacin is relatively safe regarding its nephrotoxicity, while caution is required in vulnerable patients.

Crystal-induced acute kidney injury due to ciprofloxacin

BACKGROUND

Fluoroquinolones are known to cause acute renal failure due to interstitial nephritis.

CASE PRESENTATION

Here we present an elderly woman who developed oliguric acute kidney injury (AKI) after receiving oral and intravenous ciprofloxacin in a 48-hour period. Recently, several case reports have been published in the literature regarding the presence of crystals in the urine sediment of patients treated with ciprofloxacin for different types of systemic infections. Ciprofloxacin crystals precipitate in alkaline urine and provoke renal failure through intra-tubular precipitation.

CONCLUSIONS

Conservative measures including intravenous hydration and avoidance of alkalinization of the urine can reverse this condition if applied in time.

Drug-induced impairment of renal function

Pharmaceutical agents provide diagnostic and therapeutic utility that are central to patient care. However, all agents also carry adverse drug effect profiles. While most of these are clinically insignificant, some drugs may cause unacceptable toxicity that impacts negatively on patient morbidity and mortality. Recognizing adverse effects is important for administering appropriate drug doses, instituting preventive strategies, and withdrawing the offending agent due to toxicity. In the present article, we will review those drugs that are associated with impaired renal function. By focusing on pharmaceutical agents that are currently in clinical practice, we will provide an overview of nephrotoxic drugs that a treating physician is most likely to encounter. In doing so, we will summarize risk factors for nephrotoxicity, describe clinical manifestations, and address preventive and treatment strategies.

Risk of acute kidney injury associated with the use of fluoroquinolones

BACKGROUND

Case reports indicate that the use of fluoroquinolones may lead to acute kidney injury. We studied the association between the use of oral fluoroquinolones and acute kidney injury, and we examined interaction with renin-angiotensin-system blockers.

METHODS

We formed a nested cohort of men aged 40-85 enrolled in the United States IMS LifeLink Health Plan Claims Database between 2001 and 2011. We defined cases as men admitted to hospital for acute kidney injury, and controls were admitted to hospital with a different presenting diagnosis. Using risk-set sampling, we matched 10 controls to each case based on hospital admission, calendar time (within 6 wk), cohort entrance (within 6 wk) and age (within 5 yr). We used conditional logistic regression to assess the rate ratio (RR) for acute kidney injury with current, recent and past use of fluoroquinolones, adjusted by potential confounding variables. We repeated this analysis with amoxicillin and azithromycin as controls. We used a case-time-control design for our secondary analysis.

RESULTS

We identified 1292 cases and 12 651 matched controls. Current fluoroquinolone use had a 2.18-fold (95% confidence interval [CI] 1.74-2.73) higher adjusted RR of acute kidney injury compared with no use. There was no association between acute kidney injury and recent (adjusted RR 0.87, 95% CI 0.66-1.16) or past (RR 0.86, 95% CI 0.66-1.12) use. The absolute increase in acute kidney injury was 6.5 events per 10 000 person-years. We observed 1 additional case per 1529 patients given fluoroquinolones or per 3287 prescriptions dispensed. The dual use of fluoroquinolones and renin-angiotensin-system blockers had an RR of 4.46 (95% CI 2.84-6.99) for acute kidney injury. Our case-time-control analysis confirmed an increased risk of acute kidney injury with fluoroquinolone use (RR 2.16, 95% CI 1.52-3.18). The use of amoxicillin or azithromycin was not associated with acute kidney injury.

INTERPRETATION

We found a small, but significant, increased risk of acute kidney injury among men with the use of oral fluoroquinolones, as well as a significant interaction between the concomitant use of fluoroquinolones and renin-angiotensin-system blockers.

Assessment of the role of renal organic anion transporters in drug-induced nephrotoxicity

In the present review we have attempted to assess the involvement of the organic anion transporters OAT1, OAT2, OAT3, and OAT4, belonging to the SLC22 family of polyspecific carriers, in drug-induced renal damage in humans. We have focused on drugs with widely recognized nephrotoxic potential, which have previously been reported to interact with OAT family members, and whose underlying pathogenic mechanism suggests the participation of tubular transport. Thus, only compounds generally believed to cause kidney injury either by means of direct tubular toxicity or crystal nephropathy have been considered. For each drug, or class of agents, the evidence for actual transport mediated by individual OATs under in vivo conditions is discussed. We have then examined their role in the context of other carriers present in the renal proximal tubule sharing certain substrates with OATs, as these are critical determinants of the overall contribution of OAT-dependent transport to intracellular accumulation and transepithelial drug secretion, and thus the impact it may have in drug-induced nephrotoxicity.

Drug-induced crystal nephropathy: an update

BACKGROUND

Several medications that are insoluble in human urine are known to precipitate within the renal tubules. Intratubular precipitation of either exogenously administered medications or endogenous crystals (induced by certain drugs) can promote chronic and acute kidney injury, termed crystal nephropathy. Clinical settings that enhance the risk of drug or endogenous crystal precipitation within the kidney tubules include true or effective intravascular volume depletion, underlying kidney disease, and certain metabolic disturbances that promote changes in urinary pH favoring crystal precipitation.

OBJECTIVE

Identify and review previously described and recently recognized medications that cause crystal nephropathy.

METHOD

A literature review was performed, using PubMed, Ovid, and Google Scholar, focusing on drugs (sulfadiazine, acyclovir, indinavir, triamterene, methotrexate (MTX), orlistat, oral sodium phosphate preparation, ciprofloxacin) that cause crystal nephropathy.

RESULTS/CONCLUSION

Sulfadiazine, acyclovir, indinavir, triamterene, and MTX are known to cause crystal nephropathy. Recently, several medications, including orlistat, ciprofloxacin, and oral sodium phosphate solution, along with underlying risk factors have been described as causing crystal nephropathy.

Les insuffisances rénales aiguës aux quinolones. Revue générale à propos d'une observation avec cristallisation liée à la ciprofloxacine

A 58 year-old woman developed an acute renal failure very quickly after ingestion of two 500 mg tablets of ciprofloxacin, without any other identifiable risk factor. Renal biopsy was performed. No sign of acute interstitial nephritis was observed but tubular lesions were found, accompanied by deposits of a brown-yellowish substance identified by infrared microscopy as a ciprofloxacin salt. The outcome was favourable. This observation gives the opportunity to remind the different forms of quinolone-induced renal injury and to discuss the possible ways for preventing renal side-effects related to the quinolone use.

Drug-Induced Renal Calculi

Drug-induced calculi represent 1-2% of all renal calculi. The drugs reported to produce calculi formation may be divided into two groups. The first one includes poorly soluble drugs with high urine excretion that favours crystallisation in the urine. Among poorly soluble molecules, triamterene was the leading cause of drug-containing urinary calculi in the 1970s, and it is still currently responsible for a significant number of calculi. In the last decade, drugs used for the treatment of HIV-infected patients, namely indinavir and sulfadiazine, have become the most frequent cause of drug-containing urinary calculi. Besides these drugs, about twenty other molecules may induce nephrolithiasis in patients receiving long-term treatment or high doses. Calculi analysis by physical methods, including infrared spectroscopy or x-ray diffraction, is needed to demonstrate the presence of the drug or its metabolites within the calculi. The second group includes drugs that provoke urinary calculi as a consequence of their metabolic effects. Here, diagnosis relies on careful clinical inquiry because physical methods are ineffective to differentiate between urinary calculi induced by the metabolic effects of a drug and common metabolic calculi. The incidence of such calculi, especially those resulting from calcium/vitamin D supplementation, is probably underestimated. Although drug-induced urinary calculi most often complicate high-dose, long-duration drug treatments, there also exist specific patient risk factors in relation to urine pH, urine output and other parameters, which provide a basis for preventive or curative treatment of calculi. Better awareness of the possible occurrence of lithogenic complications, preventive measures based on drug solubility characteristics and close surveillance of patients on long-term treatment with drugs with lithogenic potential, especially those with a history of urolithiasis, should reduce the incidence of drug-induced nephrolithiasis.

Nephrotoxicity and purpura associated with levofloxacin

OBJECTIVE

To report a patient with lung cancer and idiopathic myelofibrosis with myeloid metaplasia who developed purpura and acute renal failure while receiving levofloxacin, and review the existing literature on quinolone nephrotoxicity.

CASE SUMMARY

A 73-year-old white man, with a medical history of non-small-cell lung cancer and idiopathic myelofibrosis with myeloid metaplasia, was prescribed levofloxacin because of a lower urinary tract infection. Three days later, he presented with palpable purpura and erythematous skin lesions over the lower limbs and trunk, with a markedly reduced urinary output. Serum creatinine and urea nitrogen were 6.4 and 190 mg/dL, respectively. Levofloxacin was discontinued, and prednisone, furosemide, and intravenous fluids were given. The patient fully recovered over the ensuing 4 weeks.

CONCLUSIONS

Nephrotoxicity associated with levofloxacin is uncommon. Allergic interstitial nephritis or vasculitis is believed to be the underlying pathologic process. Definitive diagnosis requires performance of renal biopsy, although this is not always feasible. In this case, a return of renal function to normal, with the disappearance of purpura following the discontinuation of levofloxacin and corticosteroid treatment, supports the presumptive diagnosis of a hypersensitivity reaction to levofloxacin.

Multiple-dose pharmacokinetics and tolerability of gemifloxacin administered orally to healthy volunteers

Gemifloxacin mesylate (SB-265805-S, LB-20304a) is a potent, novel fluoroquinolone agent with a broad spectrum of antibacterial activity. The pharmacokinetics and tolerability of oral gemifloxacin were characterized in two parallel group studies in healthy male volunteers after doses of 160, 320, 480, and 640 mg once daily for 7 days. Multiple serum or plasma and urine samples were collected on days 1 and 7 and were analyzed for gemifloxacin by high-performance liquid chromatography (HPLC)-fluorescence (study 1) or HPLC-mass spectrometry (study 2). Safety assessments included vital signs, 12-lead electrocardiogram (ECG) readings, hematology, clinical chemistry, urinalysis, and adverse experience monitoring. Gemifloxacin was rapidly absorbed, with a time to maximum concentration of approximately 1 h after dosing followed by a biexponential decline in concentration. Generally, maximum concentration and area under the concentration-time curve (AUC) increased linearly with dose after either single or repeat doses. Mean +/- standard deviation values of AUC(0-tau) on day 7 were 4.92 +/- 1.08, 9.06 +/- 2.20, 12.2 +/- 3.69, and 20.1 +/- 3.67 microg x h/ml following 160-, 320-, 480-, and 640-mg doses, respectively. The terminal-phase half-life was approximately 7 to 8 h, independent of dose, and was similar following single and repeated administrations. There was minimal accumulation of gemifloxacin after multiple dosing. Approximately 20 to 30% of the administered dose was excreted unchanged in the urine. The renal clearance was 160 ml/min on average after single and multiple doses, which was slightly greater than the accepted glomerular filtration rate (approximately 120 ml/min). These data show that the pharmacokinetics of gemifloxacin are linear and independent of dose. Gemifloxacin was generally well tolerated, although one subject was withdrawn from the study after 6 days at 640 mg for mild, transient elevations of alanine aminotransferase and aspartate aminotransferase not associated with any clinical signs or symptoms. There were no other significant changes in clinical chemistry, hematology or urinalysis parameters, vital signs, or ECG readings. In conclusion, the results of these studies, combined with the antibacterial spectrum and potency, support the further investigation of once-daily administration of gemifloxacin for indications such as respiratory tract and urinary tract infections.

Fluoroquinolones in pediatrics and their nephrotoxicity in adults: minireview

In recent years there is increasing pressure to use fluoroquinolones in pediatric patients but relatively few data have been published in the literature. Therefore this paper reviews the available information about the pharmacokinetics of fluoroquinolones in children and their use in pediatric urinary tract infections, taking into account their potential as nephrotoxic agents. From the available data it seems reasonable to suggest that there is no risk of quinolone-induced nephrotoxicity and that this class of antibiotics may therefore be considered as potential candidates in urinary tract infections in children. Nevertheless adequate pharmacokinetic investigations and further studies on long-term monitoring for potential toxicity need to be conducted in pediatric populations.

Fluoroquinolone-induced renal failure

Fluoroquinolones are generally well tolerated, clinically useful antimicrobials. This paper highlights rare, but potentially serious, adverse effects involving the kidney. Other antimicrobials have long been known to cause various forms of nephrotoxicity occurring as allergic interstitial nephritis, granulomatous interstitial nephritis, necrotising vasculitis, allergic tubular nephritis or a tubular necrosis. A Medline search (1985 to May 1999) of ciprofloxacin, norfloxacin, levofloxacin, ofloxacin, trovafloxacin, enoxacin, sparfloxacin, grepafloxacin, gatifloxacin, clinafloxacin and moxifloxacin was conducted to ascertain the incidence and features of fluoroquinolone nephrotoxicity. Unfortunately, the data primarily consist of case reports and temporally related events. The incidence of these adverse effects is hard to estimate, and the cause may be multifactorial. While the use of ciprofloxacin appears to increase the risk, this may be due to its longer and more widespread use when compared with the newer agents.

Single- and multiple-dose pharmacokinetics of AM-1155, a new 6-fluoro-8-methoxy quinolone, in humans

The pharmacokinetics of AM-1155, a new 6-fluoro-8-methoxy quinolone, was examined in healthy male volunteers after the oral administration of a single dose of 100, 200, 400, or 600 mg and multiple doses of 300 mg twice daily for 6.5 days (13 total doses). Throughout the whole study period, AM-1155 was well tolerated in every subject. In the single-dose study, the concentrations in serum reached a peak between 1 and 2 h, and the peak concentrations were 0.873, 1.71, 3.35, and 5.41 micrograms/ml at the doses of 100, 200, 400, and 600 mg, respectively. The elimination half-life was 7 to 8 h, independently of the doses. The unchanged drug was excreted mainly in the urine, with 82 to 88% of the doses appearing for 72 h. The fecal recovery of the unchanged drug amounted to 5.7% for 72 h after a single oral administration of a 400-mg dose. Urinary excretion of metabolites was minimal. The serum protein binding was 20%, independently of the concentrations in serum. The concentrations in saliva were approximately 80% of those in serum. The intake of food had no effect on the pharmacokinetic parameters and urinary excretion of AM-1155 except the slight decrease in area under the concentration-time curve. The concurrent administration of probenecid prolonged the elimination half-life, increased the area under the concentration-time curve, and decreased the apparent total body clearance, renal clearance, urinary recovery of unchanged drug, and the excretion ratio (intrinsic renal clearance of AM-1155/creatinine clearance). This indicated that the tubular secretion contributed to the renal excretion of AM-1155. In the multiple-dose study, the concentrations of AM-1155 in serum and urine reached a steady state within 2 to 3 days. The measured concentrations in serum fitted well the simulation curve, which reflected the persistence of linear pharmacokinetics of AM-1155. In conclusion, AM-1155 is expected to be clinically useful because of its potent antibacterial activity and favorable pharmacokinetics.

Pharmacokinetics and tolerance of a new fluoroquinolone antimicrobial drug after single oral doses in healthy volunteers

1. The pharmacokinetics and tolerance of DV-7751a were investigated in healthy male Caucasian volunteers after single oral doses (100, 200, 400 and 800 mg). 2. DV-7751a was rapidly absorbed in the fasted state. The mean maximum concentration in plasma (Cmax) ranged from 0.27 to 1.98 micrograms/ml for the 100-800-mg dose and the mean time to reach Cmax (tmax) ranged from 1.1 to 1.9 h. The terminal half-life ranged from 8.75 to 10.0 h. A good linear correlation (r = 0.974) was found between doses from 100 to 800 mg and the resulting area under the concentration-time curve (AUC). The plasma protein binding of the drug was in the range of 57-65%. 3. Within 48 h, the cumulative urinary excretion of unchanged drug amounted to 22.0-26.8% of the dose administered. Faecal recovery of the drug up to 72 h after the 400-mg dose was about 12% of the dose given. 4. Adverse events thought to be possibly related to the drug included headache, rash, leg cramp, diarrhoea, abdominal pain, CNS depression and dizziness. DV-7751a, however, was well tolerated with no serious adverse events at any doses and all subjects completed the study. No drug crystals were observed in the urine.

Pharmacokinetics and tolerance of DU-6859a, a new fluoroquinolone, after single and multiple oral doses in healthy volunteers

The pharmacokinetics and tolerance of DU-6859a, 7-[(7S)-7-amino-5-azaspiro[2,4]heptan-5-yl]-8-chloro-6-fluor o-1-[(1R, 2S)-2-fluoro-1-cyclopropyl]-1,4-dihydro-4-oxo-3-quinolinecarboxylic acid sesquihydrate, were investigated in healthy male Japanese volunteers after single (25, 50, 100, and 200 mg) and multiple (100 mg three times a day for 6 days plus once a day on the 7th day and 50 mg every 12 h for 13 doses) oral doses. DU-6859a was well tolerated at all doses, and all 36 subjects completed the study; mild transient soft stool in five volunteers and mild transient diarrhea in one volunteer on the multiple-dose (100 mg three times a day) study were the only side effects reported. No drug crystals were observed in the urine after the single 200-mg dose and the 100-mg three times a day regimen. DU-6859a was rapidly absorbed in the fasted state. The mean maximum concentration in serum (Cmax) ranged from 0.29 to 1.86 micrograms/ml for the 25- to 200-mg dose, and the mean time to reach Cmax ranged from 1.0 to 1.3 h. The terminal half-life ranged from 4.4 to 5.0 h. The area under the curve increased dose dependently. The serum protein binding of the drug was approximately 50%. The apparent volume of distribution clearly exceeded 1 liter/kg, suggesting good tissue penetration. Within 48 h, the cumulative urinary recovery of unchanged drug amounted to 69 to 74% of the dose administered, while fecal excretion up to 48 h after the 200-mg dose accounted for ca. 3% of the dose. Food intake did not affect the rate and extend of absorption of DU-6859a to a clinically significant extent. During multiple oral dosing, the accumulation of the drug in serum was close to the theoretically predicted values, which indicated that there was virtually no drug accumulation.

Pharmacokinetics and tolerance of DU-6859a, a new fluoroquinolone, after single and multiple oral doses in healthy volunteers

The pharmacokinetics and tolerance of DU-6859a, 7-[(7S)-7-amino-5-azaspiro[2,4]heptan-5-yl]-8-chloro-6-fluor o-1-[(1R, 2S)-2-fluoro-1-cyclopropyl]-1,4-dihydro-4-oxo-3-quinolinecarboxylic acid sesquihydrate, were investigated in healthy male Japanese volunteers after single (25, 50, 100, and 200 mg) and multiple (100 mg three times a day for 6 days plus once a day on the 7th day and 50 mg every 12 h for 13 doses) oral doses. DU-6859a was well tolerated at all doses, and all 36 subjects completed the study; mild transient soft stool in five volunteers and mild transient diarrhea in one volunteer on the multiple-dose (100 mg three times a day) study were the only side effects reported. No drug crystals were observed in the urine after the single 200-mg dose and the 100-mg three times a day regimen. DU-6859a was rapidly absorbed in the fasted state. The mean maximum concentration in serum (Cmax) ranged from 0.29 to 1.86 micrograms/ml for the 25- to 200-mg dose, and the mean time to reach Cmax ranged from 1.0 to 1.3 h. The terminal half-life ranged from 4.4 to 5.0 h. The area under the curve increased dose dependently. The serum protein binding of the drug was approximately 50%. The apparent volume of distribution clearly exceeded 1 liter/kg, suggesting good tissue penetration. Within 48 h, the cumulative urinary recovery of unchanged drug amounted to 69 to 74% of the dose administered, while fecal excretion up to 48 h after the 200-mg dose accounted for ca. 3% of the dose. Food intake did not affect the rate and extend of absorption of DU-6859a to a clinically significant extent. During multiple oral dosing, the accumulation of the drug in serum was close to the theoretically predicted values, which indicated that there was virtually no drug accumulation.

Ciprofloxacin-induced granulomatous interstitial nephritis and localized elastolysis

Ciprofloxacin is known to cause acute interstitial nephritis. We report the first case of ciprofloxacin-induced granulomatous interstitial nephritis and localized elastolysis. The patient presented with acute renal failure and skin lesions following a 14-day course of ciprofloxacin administered for cellulitis. The patient had symmetric, palm-sized, tender violaceous plaques on both axillae. The renal biopsy revealed granulomatous interstitial disease. A skin biopsy revealed an elastolytic process with histocytic infiltration and calcification. After discontinuing ciprofloxacin and starting a short course of steroid therapy, the skin lesion and renal function improved promptly. The nephritis relapsed after prednisone was discontinued and responded to a second course of steroid therapy. Ciprofloxacin, like penicillin, can cause granulomatous interstitial nephritis and elastolysis. A prolonged course of steroid therapy may be indicated in patients with ciprofloxacin-induced granulomatous interstitial nephritis to avoid early relapse.

The U.S. clinical experience with lomefloxacin, a new once-daily fluoroquinolone

Lomefloxacin is a new fluoroquinolone antimicrobial agent that has undergone extensive worldwide clinical evaluation. This report summarizes the safety and efficacy of lomefloxacin in the treatment of uncomplicated urinary tract infections, complicated urinary tract infections, acute exacerbations of chronic bronchitis, and for prophylaxis during urinary tract surgery. The clinical data presented are an overview of all clinical studies conducted in the United States to date. The results have been derived from multiple studies in which patients received lomefloxacin or a comparative agent in either blinded or open-label studies. During the course of the clinical program in the United States, lomefloxacin has been compared with oral norfloxacin, ciprofloxacin, and cefaclor, as well as parenteral cefotaxime. In all instances, the once-daily oral administration of lomefloxacin was either equally effective or statistically significantly superior in clinical and/or bacteriologic efficacy to these comparative agents. In addition, the comparators were administered either two or three times per day, except in the surgical prophylaxis studies, in which single doses of each antibiotic were administered preoperatively. These results attest to the value of the convenience and simplicity of the oral dosing regimen for lomefloxacin. During the course of the clinical program, lomefloxacin was well tolerated, with most adverse events of mild to moderate severity. In general, the incidence of adverse events for patients and subjects receiving lomefloxacin was comparable to that observed in patients treated with comparator drugs. The most common adverse events were related to the gastrointestinal tract (nausea and diarrhea), the skin and appendages (photosensitivity), and the central nervous system (dizziness and headache). A sub-analysis of adverse events in the respiratory studies demonstrated that concomitant administration of lomefloxacin and theophylline does not increase the incidence of adverse events when compared to lomefloxacin alone. An additional sub-analysis also showed that the incidence of adverse events in elderly patients was similar to that in younger patients. The results of the U.S. clinical program indicate that lomefloxacin administered orally once daily is effective and well tolerated in a variety of infections of bacterial origin.

Overview of fluoroquinolone safety

The safety of the fluoroquinolone antimicrobial agents is reviewed, discussing documented and potential clinical and laboratory adverse effects and drug-drug interactions. In prospective, randomized, double-blind clinical trials comparing fluoroquinolones to nonquinolone drugs or placebo, the fluoroquinolones were not significantly different (22 studies) or were superior (5 studies) to comparison agents but were only rarely more toxic (2 studies). Adverse effects included mild gastrointestinal toxicities and less common but more problematic central nervous system toxicities. Clinically important interactions occurred with coadministration of antacids and all fluoroquinolones and with theophylline and enoxacin and to a lesser extent ciprofloxacin and pefloxacin but not other fluoroquinolones. Potential adverse effects such as cartilage damage, DNA damage, teratogenicity, and crystalluria, while of concern, have not as yet been shown to be of clinical importance. Therapy of bacterial infections in children and adolescents is relatively contraindicated, but growing clinical experience with treatment of these patients has not so far revealed serious bone or cartilage toxicity. The fluoroquinolones thus far have exhibited a favorable safety profile, but our clinical experience is still limited, and monitoring for as yet unappreciated toxicities is warranted.

Ciprofloxacin in patients with mycobacterial infections: experience in 15 patients

In vitro and animal investigations have demonstrated the antimycobacterial activity of some fluoroquinolones, including ciprofloxacin, but information regarding their clinical usefulness in mycobacterial infections is sparse. This article presents treatment results of 11 patients with tuberculosis and 4 with atypical mycobacterial infections. They were treated with combinations of ciprofloxacin and one or two other antituberculosis agents. Susceptibility of the infecting organisms to ciprofloxacin was determined in 14 of the 15 patients: in 12 of them, minimum inhibitory concentrations ranged between 0.31 and 1.25 micrograms/mL, suggesting a good level of activity. Serum concentrations of ciprofloxacin, sampled one hour after dosing and measured by a specific HPLC assay, revealed considerable variability (range 0.22-8.41 micrograms/mL). Serial plasma samples taken under controlled conditions suggested that a decreased rate of absorption was responsible for low one-hour concentrations in one of the subjects. Adverse reactions to ciprofloxacin were few and included nausea in four patients, crystalluria in one, and febrile reaction in another. A satisfactory response in terms of clinical and radiologic improvement, bacteriologic conversion, and absence of relapse was seen in 13 of the 14 patients who completed an adequate course of therapy. A controlled clinical trial of this promising antimycobacterial agent is needed.

[Comparison of the adverse effect profile of different substances such as penicillins, tetracyclines, sulfonamides and quinolones]

The penicillins, the tetracyclines and the sulfonamides have often been used in the last few decades in spite of their well-known side effects. Hypersensitivity reactions to penicillins are among the most important adverse reactions in these antibiotics; in every case a careful medical history has to be taken before a new course of penicillin treatment. The use of tetracyclines in women during the last six months of pregnancy or in children under the age of eight years is contraindicated. Patients with severe blood, kidney or liver disease should not be treated with sulfonamides. Toxic reactions to penicillin even with convulsions may occur in patients with renal insufficiency if the dosage is not adapted. The fluoroquinolones do not seem to have greater risks regarding adverse reactions than the historical compounds mentioned. Neurotoxicity is an important problem. Mild reactions are reported with incidences under 2%; severe neurotoxic side effects that require interruption of therapy are rare. Psychotic reactions, hallucinations, depressions and grand mal convulsions also belong to this category. Other side effects (skin, GI-tract) are no more frequent than with the classical antibiotics. In patients with renal insufficiency the dosage of ofloxacin has to be adapted. The cartilage lesions which are seen in juvenile rats and dogs raise the question whether or not the cases of arthralgia during therapy with older quinolones as well as under treatment with fluoroquinolones have a causal relationship. Up to date quinolones should not be prescribed in children and young adults except in cases with cystic fibrosis. The development of resistance has not been a significant problem so far.(ABSTRACT TRUNCATED AT 250 WORDS)

Pharmacokinetics and safety of single oral doses of lomefloxacin

The pharmacokinetics of 100 mg, 200 mg, 400 mg, 600 mg, and 800 mg of lomefloxacin, a quinolone antimicrobial, were examined in a single sequential rising dose, placebo-controlled, crossover study. Each of 30 healthy male subjects (6 per group) received placebo and one dose of lomefloxacin, separated by 5 days. Test results (physical examinations, laboratory and hematology panels, vital signs, neurological and ophthalmological examinations, EEG or urinalysis) revealed no clinically significant differences compared to baseline. Mean Cmax values (0.92 micrograms ml-1 to 6.99 micrograms ml-1) increased linearly with dose. Mean tmax averaged 1.13 +/- 0.5 h and mean t1/2, 7.8 +/- 1.0 h over all doses. There was a small influence of dose on the AUC0-48. Mean urinary concentrations during the first 4 h postdosing ranged from 79 to 454 micrograms ml-1. Urine concentrations remained greater than or equal to 15 micrograms ml-1 over 24 h at the lowest dose. Maximum urinary excretion rate, Rmax, ranged from 5.84 mg h-1 to 34.90 mg h-1. Dose normalized Rmax and XU96 (per cent of dose) were unaffected by dose. Mean renal clearance decreased at higher doses. In conclusion, lomefloxacin was well tolerated in doses up to 800 mg. Lomefloxacin is rapidly absorbed with an elimination half-life of approximately 8 h. The data suggest that the drug can be effectively administered once daily.