High incidence of vancomycin-associated leucopenia and neutropenia in a cardiothoracic surgical unit

Vancomycin-Induced Neutropenia With Subsequent Perioperative Readministration: A Case Report

Vancomycin (VCM), an essential antibiotic for antimicrobial-resistant Gram-positive cocci, can lead to complications such as neutropenia. Here, we present a case of a 25-year-old male with noncommunicating hydrocephalus due to an intraventricular tumor who developed neutropenia during VCM therapy. Despite the suspected VCM-induced neutropenia, short-term readministration was deemed necessary for perioperative infection prophylaxis. This patient was readministered without neutropenia. A review of the literature revealed an earlier onset of VCM-induced neutropenia than that previously reported, emphasizing the importance of vigilant monitoring. Although readministration of VCM in patients with neutropenia is uncommon, it may be feasible with careful risk assessment, particularly in cases of mild neutropenia and short-term therapy. However, the mechanisms underlying VCM-induced neutropenia remain unclear, necessitating further research on the optimal management strategies.

Clinical Outcomes of Culture-Negative and Culture-Positive Periprosthetic Joint Infection: Similar Success Rate, Different Incidence of Complications

OBJECTIVE

To compare the clinical outcomes of culture-negative periprosthetic joint infection (CN PJI) with those of culture-positive periprosthetic joint infection (CP PJI).

METHODS

This study retrospectively examined data from 77 patients who underwent revision surgery due to periprosthetic joint infection (PJI) after hip and knee arthroplasty at our center from January 2012 to June 2017. There were 37 males and 40 females, with an average age of 63.6 year. All patients were classified by Tsukayama type, according to the bacterial culture results of synovial fluid and pre- and intraoperative tissues, 24 cases were included in the CN PJI group, and 53 cases were included in the CP PJI group. All patients underwent routine blood tests, liver, renal function tests, erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) measurements. The remission rates of CN PJI and CP PJI were compared. The effects of the culture results on the curative effect were further compared by survival analysis.

RESULTS

The patients were followed regularly with an average of 29.2 months (range, 12-76 months). In total, there were 24 cases of CN PJI, with an incidence of 29.63%. The overall success rate of CN PJI group was 86.4% (19/22), and overall success rate of CP PJI group was 87.5% (42/48). The relative efficacy of various surgical options was: one-stage revision 100% (7/7), two-stage revision 96.3% (26/27), debridement and implant retention 64.3% (9/14), respectively. There was no significant difference in the success rate between the CN PJI group and the CP PJI group. The incidence of antibiotic-related complications for the CN PJI group was significantly higher than that of the CP PJI group, with 58.3% for CN PJI and 11.3% for CP PJI, respectively.

CONCLUSION

When CN PJI was treated according to the strict standards for the diagnosis and treatment, the success rate of treatment for the CN PJI group was similar to that for the CP PJI group. The incidence of antibiotic-related complications from the CN PJI group was higher than that from the CP PJI group.

Clinical and Pharmacokinetic Outcomes of Peak-Trough-Based Versus Trough-Based Vancomycin Therapeutic Drug Monitoring Approaches: A Pragmatic Randomized Controlled Trial

BACKGROUND

Vancomycin therapeutic drug monitoring (TDM) is based on achieving 24-h area under the concentration-time curve to minimum inhibitory concentration cure breakpoints (AUC24/MIC). Approaches to vancomycin TDM vary, with no head-to-head randomized controlled trial (RCT) comparisons to date.

OBJECTIVES

We aimed to compare clinical and pharmacokinetic outcomes between peak-trough-based and trough-only-based vancomycin TDM approaches and to determine the relationship between vancomycin AUC24/MIC and cure rates.

METHODS

A multicentered pragmatic parallel-group RCT was conducted in Hamad Medical Corporation hospitals in Qatar. Adult non-dialysis patients initiated on vancomycin were randomized to peak-trough-based or trough-only-based vancomycin TDM. Primary endpoints included vancomycin AUC24/MIC ratio breakpoint for cure and clinical effectiveness (therapeutic cure vs therapeutic failure). Descriptive, inferential, and classification and regression tree (CART) statistical analyses were applied. NONMEM.v.7.3 was used to conduct population pharmacokinetic analyses and AUC24 calculations.

RESULTS

Sixty-five patients were enrolled [trough-only-based-TDM (n = 35) and peak-trough-based-TDM (n = 30)]. Peak-trough-based TDM was significantly associated with higher therapeutic cure rates compared to trough-only-based TDM [76.7% vs 48.6%; p value = 0.02]. No statistically significant differences were observed for all-cause mortality, neutropenia, or nephrotoxicity between the two groups. Compared to trough-only-based TDM, peak-trough-based TDM was associated with less vancomycin total daily doses by 12.05 mg/kg/day (p value = 0.027). CART identified creatinine clearance (CLCR), AUC24/MIC, and TDM approach as significant determinants of therapeutic outcomes. All patients [n = 19,100%] with CLCR ≤ 7.85 L/h, AUC24/MIC ≤ 1256, who received peak-trough-based TDM achieved therapeutic cure. AUC24/MIC > 565 was identified to be correlated with cure in trough-only-based TDM recipients [n = 11,84.6%]. No minimum AUC24/MIC breakpoint was detected by CART in the peak-trough-based group.

CONCLUSION

Maintenance of target vancomycin exposures and implementation of peak-trough-based vancomycin TDM may improve vancomycin-associated cure rates. Larger scale RCTs are warranted to confirm these findings.

Comparative analysis of neutropenia in patients receiving prolonged treatment with ceftaroline

Objectives

Ceftaroline is often used in durations greater than that studied in clinical trials. Several retrospective, non-comparative studies have suggested a higher than anticipated incidence of neutropenia in patients receiving prolonged treatment with ceftaroline. We sought to determine if ceftaroline was associated with neutropenia by comparing the incidence with ceftaroline treatment with treatment with several comparative antibiotics.

Methods

Patients receiving 14 or more consecutive days of treatment with ceftaroline were compared with patients receiving cefazolin, daptomycin, linezolid, nafcillin or vancomycin (control group). The primary outcome was the development of neutropenia. Multivariate logistic regression and propensity score weighting using inverse probability weights with regression adjustment were used to control for confounding variables.

Results

A total of 753 patients were included (53 that received ceftaroline and 700 that received a comparative antibiotic). Ceftaroline was associated with a greater incidence of neutropenia as compared with the control group (17.0% versus 3.9%, P < 0.001). Several covariates were also associated with neutropenia and included younger age, lower baseline absolute neutrophil count, liver disease and bone and joint infections. After controlling for these confounders, receipt of ceftaroline continued to be associated with the development of neutropenia (adjusted OR 3.97, P = 0.003). Analysis after propensity score weighting confirmed this finding.

Conclusions

The results of this study suggest that prolonged treatment with ceftaroline is associated with a greater incidence of neutropenia as compared with other antibiotics that are often used for treatment of staphylococcal infections. Careful monitoring of absolute neutrophil count is recommended in patients receiving >14 days of ceftaroline.

Non-chemotherapy drug-induced neutropenia: key points to manage the challenges

Non-chemotherapy idiosyncratic drug-induced neutropenia (IDIN) is a relatively rare but potentially fatal disorder that occurs in susceptible individuals, with an incidence of 2.4 to 15.4 cases per million population. Affected patients typically experience severe neutropenia within several weeks to several months after first exposure to a drug, and mortality is ∼5%. The drugs most frequently associated with IDIN include metamizole, clozapine, sulfasalazine, thiamazole, carbimazole, amoxicillin, cotrimoxazole, ticlopidine, and valganciclovir. The idiosyncratic nature of IDIN, the lack of mouse models and diagnostic testing, and its low overall incidence make rigorous studies to elucidate possible mechanisms exceptionally difficult. An immune mechanism for IDIN involving neutrophil destruction by hapten (drug)-specific antibodies and drug-induced autoantibodies is frequently suggested, but strong supporting evidence is lacking. Although laboratory testing for neutrophil drug-dependent antibodies is rarely performed because of the complexity and low sensitivity of tests currently in use, these assays could possibly be enhanced by using reactive drug metabolites in place of the parent drug. Patients typically experience acute, severe neutropenia, or agranulocytosis (<0.5 × 10⁹ neutrophils/L) and symptoms of fever, chills, sore throat, and muscle and joint pain. Diagnosis can be difficult, but timely recognition is critical because if left untreated, there is an increase in mortality. Expanded studies of the production and mechanistic role of reactive drug metabolites, genetic associations, and improved animal models of IDIN are essential to further our understanding of this important disorder.

Glycopeptide-Induced Neutropenia: Cross-Reactivity Between Vancomycin and Teicoplanin

Objective:

To report teicoplanin-related neutropenia that developed after an episode of neutropenia induced by vancomycin therapy.

Case Summary:

A 57-year-old female suffered from osteomyelitis of the left humerus, with a white blood cell (WBC) count of 2.8 × 103/mm3 and absolute neutrophil count (ANC) of 0.28 × 103/mm3, occurring after 24 days of vancomycin therapy. Vancomycin was changed to teicoplanin and the agranulocytosis resolved 4 days later. However, a new episode of neutropenia, with a WBC count of 2.8 × 103/mm3 and ANC of 0.448 × 103/mm3, occurred 11 days after teicoplanin initiation. Agranulocytosis resolved 4 days following withdrawal of teicoplanin.

Discussion:

Because of the close time relationship between drug administration and the development of symptoms and signs, as well as between drug withdrawal and changes in WBC count and ANC, the episodes of neutropenia were suspected to be drug related. Teicoplanin-induced agranulocytosis that followed vancomycin-induced agranulocytosis suggests a possible cross-reactivity between the 2 drugs. Both reactions were categorized as probable according to the Naranjo probability scale.

Conclusions:

For all patients with vancomycin-induced neutropenia, possible cross-reactivity of teicoplanin should be monitored.

Daptomycin Use After Vancomycin-Induced Neutropenia in a Patient with Left-Sided Endocarditis

Objective:

To report a positive outcome in a patient treated with daptomycin for left-sided endocarditis associated with methicillin-resistant Staphylococcus aureus (MRSA) subsequent to vancomycin-induced neutropenia.

Case Summary:

A 55-year-old African American male was diagnosed with left-sided endocarditis, brain abscesses, and septic arthritis due to community-acquired MRSA. He began treatment with intravenous vancomycin to achieve a trough concentration of 15–20 μg/mL and oral rifampin 600 mg/day. A repair and resection of the mitral valve was completed on day 15 of hospitalization. Vancomycin was discontinued on day 36 secondary to drug-induced neutropenia (absolute neutrophil count nadir 162 cells/μL). Intravenous therapy with daptomycin 6 mg/kg every 24 hours was then initiated and the neutropenia resolved. The patient was discharged from the hospital on day 56.

Discussion:

Upon discontinuation of vancomycin, treatment options were limited to a small number of alternatives. Documented clinical experience and relevant studies are limited regarding the use of quinupristin/dalfopristin (Q/D), linezolid, trimethoprim/sulfamethoxazole (TMP/SMX), and daptomycin for the treatment of MRSA left-sided endocarditis. Daptomycin was selected because of its bactericidal qualities and its recent approval for this indication. The prognostic outlook for use of daptomycin in this treatment was uncertain; however, Q/D, linezolid, and TMP/SMX posed greater risks of failure.

Conclusions:

Treatment of MRSA left-sided endocarditis in patients intolerant to vancomycin is challenging. The positive outcome in our patient is likely attributable to aggressive vancomycin dosing and extended duration of treatment prior to the initiation of daptomycin. The use of daptomycin in this case enabled successful management of left-sided endocarditis.

Epidemiology of Vancomycin-Induced Neutropenia In Patients Receiving Home Intravenous Infusion Therapy

Background:

Vancomycin is frequently used to manage serious resistant gram-positive Infections. Neutropenia, whose epidemiology has not been well characterized, is a potentially serious adverse event associated with the use of vancomycin.

Objective:

To characterize the incidence and risk factors for development of vancomycin-induced neutropenia in patients treated with home intravenous vancomycin therapy.

Methods:

A retrospective chart review was conducted of adult patients receiving vancomycin therapy through the University of New Mexico Home Intravenous Infusion Clinic between January 1998 and December 2004. Data collection included demographics, comorbid conditions, dose and duration of vancomycin therapy, indications for vancomycin use, vancomycin concentrations, all concurrent medications, laboratory data, culture and susceptibility data, reasons for antibiotic alteration or discontinuations, all other recorded adverse events, management of adverse events, and outcomes of adverse events.

Results:

A total of 372 charts of patients managed through the clinic were reviewed and 114 patients treated with vancomycin were identified. Fourteen (12%) cases of vancomycin-induced neutropenia were identified; 4 (3.5%) cases included a reduction in absolute neutrophil count to 500 cells/mm3 or less. The mean ± SD duration of vancomycin therapy and time to neutropenia were 32 ± 29 and 26 ± 15 days, respectively. Laboratory monitoring was performed on a weekly basis and resolution of vancomycin-induced neutropenia occurred promptly after discontinuation. Total vancomycin doses used and serum concentrations were not associated with the development of neutropenia.

Conclusions:

Vancomycin-induced neutropenia may occur at a higher frequency than previously reported. Clinicians should monitor hematologic parameters at least weekly in patients receiving home intravenous vancomycin therapy.

A Case of Teicoplanin-Induced Pancytopenia Caused by Excessive Dosing

Teicoplanin is reported to be as effective as vancomycin but with minimal side effects. We report a case of teicoplanin-induced pancytopenia, which has not been demonstrated previously. A 44-year-old man with tetraplegia was treated with a diagnosis of urinary tract infection and pneumonia, and a high-dose of teicoplanin (400 mg every 12 hours) was administered for 4 days inadvertently. Although the infection rapidly improved, the patient developed pancytopenia by the fourth day of teicoplanin therapy, which was improved after reducing the dose of teicoplanin (200 mg/d). Our patient represents a probable case of teicoplanin-induced pancytopenia with adverse drug reaction probability score of 6.

Teicoplanin-induced neutropenic sepsis mimicking endocarditis

Teicoplanin is a less toxic replacement for vancomycin in most situations where resistant organisms are encountered, and is therefore the drug of choice. As a commonly used drug in cardiac surgery, we treated a case of presumptive endocarditis with teicoplanin that caused neutropenic sepsis, unmasked on withdrawal of treatment.

Management of gram-positive bacterial infections in patients with cancer

Bacterial infections, particularly those due to gram-positive bacteria, continue to predominate in patients with cancer. Coagulase-negative and coagulase-positive staphylococci and enterococci remain as common pathogenic microorganisms. Clostridium difficile has emerged as a significant pathogen. Major clinical syndromes include vascular catheter-related infection, febrile neutropenia, diarrhea and colitis. Rising antimicrobial resistance among gram-positive bacteria is of serious concern. The clinical utility of penicillin against streptococci and vancomycin against coagulase-negative and coagulase-positive staphylococci and enterococci may be rapidly diminishing. Liberal empiric use of vancomycin during neutropenic fever needs careful reconsideration. Newer promising anti-gram-positive bacterial drugs with activity against methicillin-resistant staphylococci include daptomycin, linezolid, tigecycline and telavancin. However, toxicity concerns, limited data in immunocompromised populations and high cost prevent the widespread use of these drugs among patients with cancer.

Vancomycin-induced neutropenia: is it dose- or duration-related?

OBJECTIVE

To systematically evaluate the literature to determine whether vancomycin-induced neutropenia is dose- or duration-related and provide clinicians with feasible treatment alternatives.

DATA SOURCES

A literature search of PubMed (1949-November 2010), MEDLINE (1950-November 2010), EMBASE (1980-November 2010), and International Pharmaceutical Abstracts (1970-November 2010) was performed using the terms vancomycin, neutropenia, and leukopenia. Citations from publications were reviewed for additional references.

STUDY SELECTION AND DATA EXTRACTION

Studies and case reports were included if they reported neutropenia with vancomycin administration and excluded if they did not describe vancomycin dosages and/or concentrations, or if neutropenia resolved while the patient was still receiving vancomycin. Cases with significant confounders and those in which authors provided minimal information about patients were also excluded.

DATA SYNTHESIS

Seven retrospective chart reviews (ie, case series) and 33 case reports were identified. Of these, 3 retrospective reviews and 26 case reports met inclusion criteria. To our knowledge, no prospective studies have assessed this clinical complication. Data suggest that vancomycin-induced neutropenia may not be completely related to daily dosages, total cumulative dosage, or supratherapeutic vancomycin concentrations. Furthermore, evidence suggests that neutropenia is more likely associated with therapy longer than 7 days, with the majority of episodes occurring beyond 20 days of therapy. Given these findings, a practical approach is to monitor white blood cell (WBC) count with a differential (including absolute neutrophil count) once a week in patients who are receiving vancomycin for more than 7 days.

CONCLUSIONS

Vancomycin-induced neutropenia is most likely associated with prolonged vancomycin exposure. Patients receiving vancomycin for longer than 7 days should have WBC count, differential, monitored weekly. Vancomycin should be discontinued if there is a high clinical suspicion of it causing neutropenia, and an alternative agent should be initiated. Prospective case-controlled studies are needed to better characterize this adverse event.

Tolerability of teicoplanin in 117 hospitalized adults with previous vancomycin-induced fever, rash, or neutropenia: a retrospective chart review

BACKGROUND

Vancomycin has reliable antibacterial activity against many gram-positive pathogens but is associated with many adverse events. Teicoplanin, another glycopeptide, is associated with fewer adverse events, but its use in patients with previous vancomycin-induced adverse reactions remains controversial.

OBJECTIVES

The aims of this work were to evaluate the clinical characteristics of hospitalized patients with vancomycin-induced fever (ie, drug fever), rash, or neutropenia and to examine the tolerability of teicoplanin in these patients.

METHODS

This was a retrospective review of the medical charts of patients aged >or=18 years who were hospitalized between January 2002 and October 2007 at National Cheng Kung University Hospital in Tainan, Taiwan. Patients were included if they experienced drug-induced fever (ie, "drug fever"), rash, or neutropenia during vancomycin treatment. Their antimicrobial therapy was subsequently switched to teicoplanin. Clinical information and the development of drug fever, rash, or neutropenia with teicoplanin were determined from the charts.

RESULTS

Antibiotic therapy was switched to teicoplanin in 117 patients with vancomycin-induced fever alone (n = 24), rash alone (n = 77), both drug fever and rash (n = 8), or neutropenia (n = 8). The mean (SD) age of these patients was 53.1 (22.8) years, and 65 (56%) were male. The major clinical indications for vancomycin therapy among these patients were wound infections (21%), respiratory tract infections (14%), and bacteremia (13%). The dosages for vancomycin ranged from 1 g every 5 days to 1 g BID, and for teicoplanin ranged from 400 mg daily to 400 mg q72h, adjusted by the degree of renal dysfunction. Overall, 12 patients with vancomycin-induced fever (n = 2), rash (n = 6), or neutropenia (n = 4) subsequently developed teicoplanin-induced fever (n = 3), rash (n = 3), or neutropenia (n = 6). Specifically, of 8 patients with vancomycin-induced neutropenia, 4 (50%) subsequently developed neutropenia after switching to teicoplanin. Vancomycin- and teicoplanin-induced neutropenia was often noted after 1 week of treatment. Among patients with vancomycin-induced fever, rash, or neutropenia, there were no differences between patients with or without teicoplanin-induced fever, rash, or neutropenia in terms of age, sex, weight, dosage or duration of vancomycin therapy, dosage of teicoplanin, or underlying disease. There was no difference in mortality rates between patients with or without teicoplanin-induced fever, rash, or neutropenia. The cause of all deaths was progression of infectious or underlying disease, unrelated to vancomycin or teicoplanin use.

CONCLUSIONS

Based on this retrospective chart review of hospitalized patients with vancomycin-induced fever, rash, or neutropenia, only 10% experienced subsequent teicoplanin-induced fever, rash, or neutropenia. However, it should be noted that half of the patients with vancomycin-induced neutropenia developed teicoplanin-induced neutropenia.

Vancomycin-induced immune thrombocytopenia

BACKGROUND

Vancomycin has only rarely been implicated as a cause of thrombocytopenia, and there is only limited evidence that this complication is caused by immune mechanisms. We conducted a study to determine whether thrombocytopenia is caused by vancomycin-dependent antibodies in patients being treated with vancomycin.

METHODS

We identified and characterized vancomycin-dependent, platelet-reactive antibodies in patients who had been referred for testing during a 5-year period because of a clinical suspicion of vancomycin-induced thrombocytopenia. We obtained clinical information about the patients from their referring physicians.

RESULTS

Drug-dependent, platelet-reactive antibodies of the IgG class, the IgM class, or both were identified in 34 patients, and clinical follow-up information was obtained from 29 of these patients. The mean nadir platelet count in these patients was 13,600 per cubic millimeter, and severe bleeding occurred in 10 patients (34%). Platelet levels returned to baseline in all 26 surviving patients after vancomycin was stopped. In 15 patients, the drug was continued for 1 to 14 days while other possible causes of thrombocytopenia were investigated. Vancomycin-dependent antibodies were not found in 25 patients who had been given vancomycin and in whom thrombocytopenia did not develop.

CONCLUSIONS

Severe bleeding can occur in patients with vancomycin-induced immune thrombocytopenia. The detection of vancomycin-dependent antiplatelet antibodies in patients receiving the antibiotic in whom thrombocytopenia develops, and the absence of antibodies in patients given the drug in whom platelet counts remain stable, indicate that these antibodies are the cause of the thrombocytopenia.

Thiopental-Induced Neutropenia in Two Patients with Severe Head Trauma

Thiopental has been used for decades in the treatment of refractory intracranial hypertension in patients with traumatic and nontraumatic head injuries. Commonly reported adverse effects include hypotension, hypokalemia, respiratory complications, and hepatic dysfunction. Neutropenia has rarely been reported as an adverse effect of thiopental. We witnessed probable thiopental-induced neutropenia in two patients with traumatic brain injuries who developed increased intracranial hypertension that was refractory to standard therapy. Based on a MEDLINE search of published case reports and literature, we propose two mechanisms by which thiopental-related neutropenia might be explained. The first is inhibition of inflammatory mediator nuclear factor-kappa B (NF-kappa B), leading to granulocyte apoptosis. The second mechanism involves inhibition of calcineurin. Although the precise link between these two mechanisms has not been elucidated, calcineurin is known to regulate NF-kappa B activity. Development of neutropenia does not appear to be correlated with time but may correlate with plasma concentrations of thiopental. The optimum management of drug-induced neutropenia is unclear. The decision to discontinue thiopental in patients who develop neutropenia should be made by weighing the risks versus benefits. Broad-spectrum antibiotics may be required in the presence of fever. The role of hematopoietic growth factors such as granulocyte colony-stimulating factor is not yet defined. Given the adverse infectious consequences of neutropenia, it is essential to closely monitor neutrophil counts in patients receiving thiopental.

Vancomycin-induced neutropenia in a patient positive for an antineutrophil antibody

A 48-year-old man, hospitalized after experiencing subarachnoid hemorrhage secondary to a basilar aneurysm, received vancomycin for methicillin-resistant Staphylococcus aureus sepsis. He developed neutropenia 16 days after the start of vancomycin therapy, and his white blood cell count decreased to a nadir of 1200 cells/mm3. Vancomycin was discontinued, and granulocyte-colony stimulating factor (G-CSF) therapy was begun. The patient was rechallenged with a single dose of vancomycin 1 g in preparation for intraarterial aneurysm coiling. His white blood cell count dropped to 600 cells/mm3 but returned to normal with continued G-CSF therapy. A diagnosis of vancomycin-induced neutropenia was considered. Subsequent testing by granulocyte agglutination and granulocyte immunofluorescence assays revealed that his serum was positive for an antigranulocyte antibody. A test for HLA antibody reactivity was negative. Monoclonal antibody immobilization of granulocyte antigens assay failed to determine the antigen specificity of his granulocyte antibody.

[Severe agranulocytosis induced by carbamazepine (Tegretol)]

We describe a case of severe drug-induced agranulocytosis, with the risk of a lethal outcome in a patient with a posttraumatic tetraplegia. Intercurrent complications required numerous medicaments. One month after admission, the neutrophil count decreased for ten days until a nadir of 70.mm-3, associated with an infectious syndrome. The bone marrow biopsy showed a severe granulocyte hypoplasia with absence of final differentiation. Administration of ienograstime (granulocyte stimulating factor) was efficient. In this patient, carbamazepine was the most probable causal factor for agranulocytosis. However, other medicaments, mainly antibiotics, could have been contributing factors.

Vancomycin-induced neutropenia associated with fever: similarities between two immune-mediated drug reactions

A 39-year-old woman being treated for osteomyelitis with vancomycin developed severe neutropenia and drug fever. After she discontinued therapy, both disorders quickly resolved. These adverse reactions have rarely been reported with vancomycin, and share many similarities with regard to clinical features and postulated mechanisms of induction. To our knowledge this is the first case documenting drug fever as a principal component of vancomycin-induced neutropenia, and provides further evidence in support of an immune-mediated mechanism.

Comparative safety of teicoplanin and vancomycin

Teicoplanin have different safety profiles which can affect choice. Nephrotoxicity is significantly less likely to occur during treatment with teicoplanin than vancomycin when an aminoglycoside is being given concurrently. 'Red man' syndrome is a troublesome effect of vancomycin infusion which is extremely uncommon with teicoplanin use. Rash and fever can be dose-related phenomena but patients reacting to one glycopeptide may not react to both. Although thrombocytopenia is more frequent with teicoplanin, it is reversible and seldom seen at standard doses.

Agranulocytosis induced by vancomycin or ticarcillin/clavulanate

OBJECTIVE

To reacquaint clinicians with a reportedly rare adverse event of agranulocytosis occurring after long-term administration of vancomycin and ticarcillin/clavulanate, with a subsequent review of other reported cases in the literature.

CASE SUMMARY

A 45-year-old white woman with spina bifida developed agranulocytosis (2.7 x 10(3)/mm3 white blood cells with only 3% polymorphonuclear leukocytes and no reported eosinophils or basophils) after long-term administration of vancomycin and ticarcillin/clavulanate for decubitus ulcers and chronic osteomyelitis. Consequently, the cell counts rebounded rapidly on discontinuation of both medications and returned to normal within 1 week.

DISCUSSION

The incidence of vancomycin-associated neutropenia is presumably rare, but the increased use of vancomycin may disclose a more frequent occurrence. It is suggested that the mechanism for the reaction is immunologically mediated, yet this remains unclear. Although it is difficult to determine the causative agent in this case, vancomycin was most suspect clinically. Ticarcillin/clavulanate is less likely because our patient has since been readmitted and treated with oxacillin, imipenem/cilastatin, and amoxicillin/clavulanate without affecting the white blood cell count. In that regard, it could be reasoned that an immunologic reaction to ticarcillin would have resulted in a similar outcome with other penicillins.

CONCLUSIONS

This case serves as a reminder to clinicians that patients receiving long-term treatment with vancomycin should have their white blood cell count monitored at least weekly.

Drug-induced immune neutropenia

Drug-induced immune-mediated neutropenia is a serious complication of therapy with many different drugs. Its clinical presentation and outcome are highly variable. In addition to the drugs listed in this review it is likely that many other drugs also cause immune-mediated neutropenia but drug-dependent neutrophil antibodies were not reported because of the lack of widespread availability of testing. With the exception of quinine-dependent antibodies in three patients, the neutrophil antigens recognized by the drug-dependent antibodies are not known; however, the recent development of MAIGA assays will likely help identify the antigens other drug-dependent neutrophil antibodies recognize.