Gentamicin ototoxicity in continuous ambulatory peritoneal dialysis

Pharmacokinetics of Intraperitoneal Vancomycin and Amikacin in Automated Peritoneal Dialysis Patients With Peritonitis

Objective: The study aimed to evaluate the vancomycin and amikacin concentrations in serum and dialysate for automatic peritoneal dialysis (APD) patients.

Methods: A total of 558 serum and dialysate samples of 12 episodes of gram-positive and 18 episodes of gram-negative peritonitis were included to investigate the relationship between vancomycin and amikacin concentrations in serum and dialysate on the first and third days of treatment. Samples were analysed 30, 120 min, and 48 h after intraperitoneal administration of vancomycin in peritonitis caused by gram-positive agents and 30, 120 min, and 24 h after intraperitoneal administration of amikacin in peritonitis caused by gram-negative agents. Vancomycin was administered every 72 h and amikacin once a day. The target therapeutic concentration of amikacin was 25–35 mg/l at the peak moment and 4–8 mg/l at the trough moment; and after 48 h for vancomycin, 15–20 mg/l at the trough moment.

Results: For peritonitis caused by gram-negative agents, at the peak moment, therapeutic levels of amikacin were reached in dialysate in 80.7% of patients with evolution to cure and in 50% of patients evaluated as non-cure (p = 0.05). At the trough moment, only 38% were in therapeutic concentrations in the dialysate in the cure group and 42.8% in the non-cure group (p = 1). Peak plasma concentrations were subtherapeutic in 98.4% of the samples in the cure group and in 100% of the non-cure group. At the trough moment, therapeutic concentrations were present in 74.4% of the cure group and 71.4% of the non-cure group (p = 1). Regarding vancomycin and among gram-positive agents, therapeutic levels were reached at the peak moment in 94% of the cure group and 6% of the non-cure group (p = 0.007). After 48 h, 56.8% of the cure group had a therapeutic serum concentration whereas for the non-cure group it was only 33.3% (p = 0.39).

Conclusion: Despite a small sample size, we demonstrated peak dialysate amikacin level and peak serum vancomycin level correlates well with Gram-negative and Gram positve peritonitis cure, respectively. It is suggested to study the antibiotics pharmacodynamics for a better understanding of therapeutic success in a larger sample.

Pharmacokinetics of Once-Daily Ip Gentamicin in Capd Patients

Objective

This study aimed to investigate the pharmacokinetic characteristics of once-daily intraperitoneal (IP) gentamicin in continuous ambulatory peritoneal dialysis (CAPD) patients.

Design

Prospective, nonrandomized, open study.

Setting

CAPD outpatient clinic in a teaching hospital.

Patients

Ten volunteer CAPD patients without peritonitis.

Interventions

Each patient received a single IP dose of 0.6 mg/kg of gentamicin. Blood and dialysate samples were collected at 0,0.5,1, 2, 3,6 (end of first dwell), and 24 hours after the administration of IP gentamicin. Any urine produced over the 24hour study period was also collected. The dialysate concentration/time data were fitted to a monoexponential curve for all patients.

Results

The bioavailability was 56±11% over a six hour dwell. The mean serum elimination half-life (t1/2) was 35.8 hours. The volume of distribution was 0.23±0.08 L/kg. Equilibration of gentamicin across the peritoneal membrane was rapid, with a t½ equilibration of 4.5 hours. The peritoneal clearance was 5.74±1.5 mL/min. Patients with residual renal function had significantly higher systemic gentamicin clearances (7.36±1.46 mL/min) than those of anuric patients (4.76±1.08 mL/min, p < 0.024).

Conclusion

Currently recommended doses of oncedaily IP gentamicin for the treatment of peritonitis may not produce the desired therapeutic serum and dialysate concentrations over 24 hours for effective treatment of peritonitis.

Review of Antibiotic Dosing with Peritonitis in APD

Peritonitis is the leading cause of transfer from peritoneal dialysis (PD) to hemodialysis (HD). It is also the leading cause of hospitalization of PD patients. The usual treatment of peritonitis for automated PD (APD) patients consists of antibiotics given once daily in the long dwell. However, the once-daily antibiotic dosing recommendations are based primarily on studies with continuous ambulatory PD (CAPD) regimens. Published studies on antibiotic dosing in APD are very limited. We will review the scant literature on this topic. It is possible that extrapolating once-daily dosing from CAPD to APD may lead to underdosing. There is a need for further pharmacokinetic studies of antibiotic dosing in APD.

Long-Term Protective Effect of N-Acetylcysteine against Amikacin-Induced Ototoxicity in End-Stage Renal Disease: A Randomized Trial

BACKGROUND

The aim of the study is to evaluate the long-term protective effect of N-acetylcysteine (NAC), an antioxidant agent, against aminoglycoside (AG)-induced ototoxicity.

METHODS

A total of 40 patients receiving continuous ambulatory peritoneal dialysis (CAPD) and having their first peritonitis attacks and planned to be treated with AGs were enrolled in the study. They were randomized into 2 groups: 1 group received additional NAC and the other did not. All patients underwent hearing tests with pure tone audiometry (PTA) after the diagnosis, at 1 month and 12 months and at the same time the tumor necrosis factor (TNF)-α and interleukin (IL)-6 levels were measured.

RESULTS

Patients taking NAC had better hearing test results in both ears at 1 month except 2,000 Hz for the left ear, which wasn't significantly different between the 2 groups. Although patients taking NAC had generally better PTA results at 12 months, differences between the 2 groups were not statistically significant. Baseline IL-6 level was significantly higher in the NAC group than the control group. Both TNF-α and IL-6 levels at 1 month were significantly lower in the NAC group than in the control group. On the other hand, there was no significant difference between the 2 groups in terms of TNF-α and IL-6 levels at 12 months.

CONCLUSIONS

The results of the current study showed that NAC, a potent anti-inflamatory drug, may be otoprotective, but that the effect is not long-lasting.

The role of monitoring gentamicin levels in patients with gram-negative peritoneal dialysis-associated peritonitis

BACKGROUND

There is limited available evidence regarding the role of monitoring serum gentamicin concentrations in peritoneal dialysis (PD) patients receiving this antimicrobial agent in gram-negative PD-associated peritonitis.

METHODS

Using data collected in all patients receiving PD at a single center who experienced a gram-negative peritonitis episode between 1 January 2005 and 31 December 2011, we investigated the relationship between measured serum gentamicin levels on day 2 following initial empiric antibiotic therapy and subsequent clinical outcomes of confirmed gram-negative peritonitis.

RESULTS

Serum gentamicin levels were performed on day 2 in 51 (77%) of 66 first gram-negative peritonitis episodes. Average serum gentamicin levels on day 2 were 1.83 ± 0.84 mg/L with levels exceeding 2 mg/L in 22 (43%) cases. The overall cure rate was 64%. No cases of ototoxicity were observed. Day-2 gentamicin levels were not significantly different between patients who did and did not have a complication or cure. Using multivariable logistic regression analysis, failure to cure peritonitis was not associated with either day-2 gentamicin level (adjusted odds ratio (OR) 0.96, 95% confidence interval (CI) 0.25 - 3.73) or continuation of gentamicin therapy beyond day 2 (OR 0.28, 0.02 - 3.56). The only exception was polymicrobial peritonitis, where day-2 gentamicin levels were significantly higher in episodes that were cured (2.06 ± 0.41 vs 1.29 ± 0.71, p = 0.01). In 17 (26%) patients receiving extended gentamicin therapy, day-5 gentamicin levels were not significantly related to peritonitis cure.

CONCLUSION

Day-2 gentamicin levels did not predict gentamicin-related harm or efficacy during short-course gentamicin therapy for gram-negative PD-related peritonitis, except in cases of polymicrobial peritonitis, where higher levels were associated with cure.

Correlation between hearing loss and peritonitis frequency and administration of ototoxic intraperitoneal antibiotics in patients with CAPD

AIM

Aminoglycosides have been used in the treatment of CAPD peritonitis despite their potential risk for ototoxicity. The ototoxicity risk of intraperitoneally administered aminoglycosides has been investigated by a number of studies. However, their results are somewhat conflicting. The aim of the present study was to examine the frequency of hearing loss and the correlation between the repeated doses of aminoglycosides and hearing loss in CAPD peritonitis therapy.

METHODS

Hearing functions of the CAPD patients who had developed peritonitis and had been treated with various antibiotics including aminoglycosides were compared with those CAPD patients who had never developed peritonitis. Threshold values for hearing were determined through "pure tone audiometry" measurements.

RESULTS

Hearing threshold levels of the patients with history of peritonitis were found to be significantly higher in both lower [pure tone averages - 1 (PTA-1)] and higher [pure tone averages - 2 (PTA-2)] frequencies, when compared to the ones with no history of peritonitis (p values were 0.001 and 0.007, respectively).

CONCLUSION

The present study showed that intraperitoneal aminoglycoside administration in CAPD patients is associated with the development of hearing loss. The severity of hearing loss may range from mild hearing loss to profound deafness. A remarkable correlation exists between the severity of the hearing loss and the repeated and total aminoglycoside dose received.

Aminoglycoside-Induced Vestibular Injury: Maintaining a Sense of Balance

Objective

To describe the mechanism and risk factors for the development of aminoglycoside-induced vestibular injury and discuss their implications for therapeutic monitoring of aminoglycoside antibiotics.

Data Sources:

A MEDLINE search (1975–January 2008) was performed to identify literature on aminoglycoside-induced vestibular injury and risk factors associated with this outcome and their impact on therapeutic drug monitoring. Additional references were identified through review of bibliographies of identified articles.

Study Selection And Data Extraction:

Data on the mechanisms of vestibular toxicity and its development in association with aminoglycoside exposure were extracted from identified references.

Data Synthesis:

The mechanism leading to the development of irreversible vestibular injury from exposure to aminoglycosides appears to be through the excessive production of oxidative free radicals. This production and subsequent toxicity appears to be a time-dependent process and is unrelated to dose or serum concentration. For similarly designed studies, the pooled incidence of vestibular toxicity is 10.9% for gentamicin, 7.4% for amikacin, 3.5% for tobramycin, and 1.1% for netilmicin. Current evidence suggests that this form of drug toxicity is not restricted to traditionally dosed systemic therapy, since intraperitoneal administration, high-dose once-daily administration, topical inhalation, and eardrop administration have all been associated with the development of this adverse outcome.

Conclusions:

Given the lack of association between serum concentrations and vestibulotoxicity, it is imperative for the pharmacist to interview the patient and not focus solely on maintaining target range drug concentrations. Minimizing the duration of exposure to aminoglycosides is recommended to reduce the risk from this form of drug toxicity.

Peritoneal dialysis catheter replacement: "save the patient and not the catheter"

A 63-year-old man on ambulatory peritoneal dialysis (APD) developed peritonitis with Enterococcus faecalis, treated with 2 g intraperitoneal (IP) vancomycin, with rapid clearing of the effluent white blood cells, but persistence of positive cultures. Vancomycin was redosed on day 8 (2 g IP), and then weekly. Gentamicin 140 mg IP loading dose, followed by 40 mg IP once a day was added after cultures were still positive at 2 weeks. The two drugs were continued for six additional weeks. Although the patient was asymptomatic, the effluent cultures continued to grow E. faecalis and the catheter was replaced 2 months after the onset of peritonitis. There was no evidence of either tunnel infection or intra-abdominal abscess. Refractory peritonitis is defined as continuation of peritonitis after 5 days of appropriate therapy. This patient had persistently positive cultures but quickly became asymptomatic and signs of inflammation resolved readily. The most likely etiology appears to have been colonization of the slime layer of the intra-abdominal portion of the catheter with the organism. The vancomycin dosing schedule may have played a role in the persistently positive cultures. A recent pharmacokinetic study suggested that patients on APD require 35 mg/kg IP of vancomycin as a loading dose, followed by 15 mg/kg IP once a day, given in a long day exchange. Simultaneous placement and removal as a single procedure was successful in this patient and can be done safely in patients whose effluent white blood cell count (WBC) is less than 100/mm3. Most patients can then be subsequently managed by doing supine dialysis (using a cycler) with decreased exchange volumes and a dry abdomen until healing occurs (usually 1-2 weeks). In this way hemodialysis can be avoided. By minimizing the effect on the patient's lifestyle, the patient is more likely to agree to a catheter exchange.

Protection from ototoxicity of intraperitoneal gentamicin in guinea pig

BACKGROUND

Aminoglycoside antibiotics are common to treat peritonitis and exit-site infections in patients on peritoneal dialysis. Ototoxicity (loss of hearing or balance) is a well-documented adverse effect of aminoglycosides, and severe ototoxic reactions have been noted in patients receiving these drugs by intraperitoneal lavage. We have proposed a free-radical hypothesis for the mechanism of aminoglycoside ototoxicity and suggested a therapeutic prevention by the concomitant administration of antioxidants or iron chelators. Here we investigate whether 2, 3-dihydroxybenzoate can prevent the ototoxicity of intraperitoneal gentamicin.

METHODS

Two strains of pigmented guinea pigs received daily intraperitoneal injections of gentamicin. Both strains developed ototoxicity, although different dosages were needed to produce similar auditory deficits (120 mg gentamicin base/kg body weight daily for 19 days vs. 135 mg/kg for 14 days). Dihydroxybenzoate was administered intraperitoneally once or twice daily. Auditory thresholds were measured by evoked brain stem response. Pathology was assessed as a loss of sensory cells in surface preparations of the organ of Corti.

RESULTS

The auditory threshold shifts and hair cell loss were similar to the pathology observed following subcutaneous injections of gentamicin. Animals sustained almost complete loss of outer hair cells in the basal cochlea and a progressive hearing loss with threshold shifts of 60 dB at 18 kHz. The concomitant administration of dihydroxybenzoate significantly attenuated the threshold shift to less than 30 dB and reduced the loss of hair cells. The treatment with dihydroxybenzoate did not affect serum gentamicin levels.

CONCLUSIONS

Antioxidant therapy is a promising approach to prevent aminoglycoside-induced hearing loss following intraperitoneal application.