Impact of Low-Dose Fluconazole on Tacrolimus Dosing in Renal Transplant

BACKGROUND

The interaction between azole antifungal therapy and immunosuppressant tacrolimus (TAC) is a barrier to use.

OBJECTIVE

This study quantified the drug interaction between low-dose fluconazole (LDF) and TAC to determine the appropriate TAC dose adjustment when used concurrently in renal transplant recipients.

METHODS

We conducted a single-center retrospective chart review of renal transplant patients >18 years who received LDF or nystatin (NYS), and TAC. The primary outcome was the difference in tacrolimus total daily dose (TAC TDD) for LDF versus NYS groups. Secondary outcomes included days with supratherapeutic, therapeutic and subtherapeutic tacrolimus levels, time to therapeutic level, incidence of adverse drug reactions and graft rejection.

RESULTS

We evaluated 94 patients and included 81. Low-dose fluconazole received a greater TAC TDD prior to post-operative day (POD) 10 (10.5 ± 4.7 mg vs. 7.1 ± 4.5 mg, p < 0.001), but a decreased TAC TDD POD 10 - 30 (8.6 ± 2.2 mg vs. 9.8 ± 0.8 mg, p < 0.001) and following LDF discontinuation (6.9 ± 0.1 mg vs. 9.0 ± 0.4 mg, p < 0.001). Low-dose fluconazole had more patient-days with supratherapeutic (17.9 ± 7.0 vs. 13.9 ± 8.5; p = 0.02) but fewer with subtherapeutic (6.7 ± 5.7 vs. 12.9 ± 7.2; p < 0.01) TAC levels. There was no difference in patient-days with therapeutic TAC levels (15.9 ± 5.8 vs. 14.4 ± 6.6, p = 0.28), meanwhile LDF required less patient-days to therapeutic TAC level (7.1 ± 2.7 vs. 11.5 ± 7.7; p < 0.01). There was no difference in adverse drug reactions between groups and no incidence of graft rejection.

CONCLUSION

A 20% reduction in TAC TDD is warranted in renal transplant patients when used concomitantly with LDF to achieve therapeutic levels.

Treatment of heparin-induced thrombocytopenia before and after the implementation of a hemostatic and antithrombotic stewardship program

In October 2013, we implemented a hemostatic and antithrombotic (HAT) stewardship program with the primary focus of ensuring appropriate use of intravenous direct thrombin inhibitors (DTI) in patients with heparin-induced thrombocytopenia (HIT). We sought to compare the duration and cost of DTI therapy for the management of HIT before and after implementation of the HAT stewardship program. Following institutional review board approval, we conducted a single center, retrospective chart review of all patients with a suspected diagnosis of HIT as assessed by an anti-heparin-PF4 enzyme-linked immunosorbent assay 6 months pre-HAT and post-HAT implementation. Patients were excluded if they were initiated on a DTI at an outside hospital, had a prior episode of HIT, or received mechanical circulatory support. Clinical characteristics, including demographics, comorbidities, medications, laboratory values, clinical and safety outcomes, length of stay, and mortality, were collected. A total of 592 patients were included; 333 patients were evaluated pre-HAT, while 259 patients were evaluated post-HAT. The mean duration of DTI treatment was significantly decreased in the post-HAT cohort (6.64 vs 5.17 days, p = 0.01), primarily driven by decreased duration of use for patients with suspected HIT (4.07 vs 2.86 days, p = 0.01). The HAT Stewardship program demonstrated a total decrease in annual costs associated with the diagnosis and management of HIT of $248,500. Our results indicate that the implementation of the HAT stewardship program had a significant impact on reducing the duration and costs of DTI therapy and the costs of laboratory evaluations in the management of HIT at our institution.

Direct Thrombin Inhibitor Resistance and Possible Mechanisms

Objective: To report 3 cases in which doses of bivalirudin higher than commonly used in clinical practice were required in order to achieve therapeutic anticoagulation as monitored by the activated partial thromboplastin time (aPTT). Case Summary: The medical records of 3 patients who required large doses of bivalirudin to remain therapeutic were thoroughly reviewed. In all 3 patients, bivalirudin was initiated at a rate appropriate for the patients' renal function and titrated using a nurse-driven protocol with recommended dose adjustments based on aPTT. Indications for bivalirudin were anticoagulation in intra-aortic balloon pump, treatment of deep vein thrombosis, and heparin-induced thrombocytopenia with thrombosis. Target aPTT was achieved between 25.5 and 134 hours after initiation despite appropriate titration intervals per protocol. Discussion: Bivalirudin is a direct thrombin inhibitor frequently used off-label for the medical management of heparin-induced thrombocytopenia. It typically exhibits predictable, dose-dependent anticoagulation. Heparin-induced thrombocytopenia was suspected in 2 of the 3 cases and confirmed in 1. In all 3 patients, target aPTT was initially achieved with doses between 0.456 and 1.0 mg/kg/h after a median of 30.7 hours; up to 1.8 mg/kg/h was required to maintain therapeutic aPTT. In 2 of the cases, the international normalized ratio also increased unexpectedly upon achievement of therapeutic aPTT values. Conclusion: Direct thrombin inhibitors may be subject to resistance mechanisms similar to those previously described in patients receiving heparin. The anticoagulation status of these patients remains unknown.

Evaluation of sedatives, analgesics, and neuromuscular blocking agents in adults receiving extracorporeal membrane oxygenation

PURPOSE

The objective of this study was to evaluate the use of sedative, analgesic, and neuromuscular blocking agents (NMBAs) in patients undergoing extracorporeal membrane oxygenation (ECMO) support.

MATERIALS AND METHODS

This was a 2-year, prospective, observational study of adult intensive care unit patients on ECMO support for more than 48hours.

RESULTS

We analyzed 32 patients, including 15 receiving VA (venoarterial) ECMO and 17 VV (venovenous) ECMO. The median daily dose of benzodiazepines (midazolam equivalents) was 24mg, and the median daily dose of opioids (fentanyl equivalents) was 3875 μg. There was a moderate negative correlation between the day of ECMO and the median daily benzodiazepine dose (r=-0.5515) and a very weak negative correlation for the median daily opioid dose (r=-0.0053). On average, patients were sedated to Richmond Agitation Sedation Scale scores between 0 and -1. Continuous infusions of opioids, benzodiazepines, propofol, dexmedetomidine, and NMBAs were administered on 404 (85.1%), 199 (41.9%), 95 (20%), 32 (6.7%), and 60 (12.6%) ECMO days, respectively. Patients in the VA arm received a continuous infusion opioid (96.4% vs 81.6% days; P<.001) and benzodiazepine (58.2% vs 37.0% days; P<.001) more frequently.

CONCLUSIONS

Patients received relatively low doses of sedatives and analgesics while at a light level of sedation on average. Patients rarely required neuromuscular blockade.

Pathophysiology, assessment, and management of pain in critically ill adults

PURPOSE

The pathophysiology of pain in critically ill patients, the role of pain assessment in optimal pain management, and pharmacologic and nonpharmacologic strategies for pain prevention and treatment are reviewed.

SUMMARY

There are many short- and long-term consequences of inadequately treated pain, including hyperglycemia, insulin resistance, an increased risk of infection, decreased patient comfort and satisfaction, and the development of chronic pain. Clinicians should have an understanding of the basic physiology of pain and the patient populations that are affected. Pain should be assessed using validated pain scales that are appropriate for the patient's communication status. Opioids are the cornerstone of pain treatment. The use of opioids, administered via bolus dosing or continuous infusion, should be guided by patient-specific goals of care in order to avoid adverse events. A multimodal approach to pain management, including the use of regional analgesia, may improve patient outcomes and decrease opioid-related adverse events, though there are limited relevant data in adult critically ill patient populations. Nonpharmacologic strategies have been shown to be effective adjuncts to pharmacologic regimens that can improve patient-reported pain intensity and reduce analgesic requirements. Analgesic regimens need to take into account patient-specific factors and be closely monitored for safety and efficacy.

CONCLUSION

Acute pain management in the critically ill is a largely underassessed and undertreated area of critical care. Opioids are the cornerstone of treatment, though a multimodal approach may improve patient outcomes and decrease opioid-related adverse events.

Early vasopressin reduces incidence of new onset arrhythmias

PURPOSE

The objective of this study was to determine the effect of early vs late vasopressin therapy on catecholamine dose and duration.

MATERIALS AND METHODS

We conducted a single-center, retrospective chart review of adult patients admitted to the medical intensive care unit between January 2010 and December 2011 with septic shock requiring catecholamine and vasopressin therapy. Patients were included in the early group if vasopressin was initiated within 6 hours and the late group if vasopressin was initiated between 6 and 48 hours of catecholamine(s).

RESULTS

Duration of catecholamine and vasopressin therapy was similar between the 35 patients in the early group and the 36 in the late group. Vasopressin therapy was associated with a decrease in catecholamine requirements in both groups. Early vasopressin was associated with fewer new onset arrhythmias (37.1% vs 62.9%, P<.001). There was no difference in mortality, hospital, or intensive care unit length of stay between the early and late group vasopressin groups (88.6% vs 88.9%, P=1; 14 vs 10 days, P=.48; 9 vs 7 days, P=.71, respectively).

CONCLUSIONS

Early initiation of vasopressin therapy in adult critically ill patients with septic shock was associated with no difference in total catecholamine requirements but decreased incidence of new onset arrhythmias.

Role of dexmedetomidine in adults in the intensive care unit: an update

PURPOSE

The role of dexmedetomidine for the management of pain, agitation, and delirium in adult patients in the intensive care unit (ICU) is reviewed and updated.

SUMMARY

Searches of MEDLINE (July 2006-March 2012) and an extensive manual review of journals were performed. Relevant literature with a focus on data published since our last review in 2007 was evaluated for topic relevance and clinical applicability. Optimal management of pain, agitation, and delirium in ICUs requires a systematic and multimodal approach aimed at providing comfort while maximizing outcomes. Dexmedetomidine is among multiple agents, including opioids, propofol, benzodiazepines, and antipsychotics, used to facilitate and increase patients' tolerability of mechanical ventilation. This article reviews the newest evidence available for dexmedetomidine use for sedation and analgesia in medical-surgical ICUs. Adverse effects associated with dexmedetomidine were similar among the studies examined herein. The most common adverse effects with dexmedetomidine were bradycardia and hypotension, in some cases severe enough to warrant the use of vasoactive support. Due to the adverse events associated with rapid dosage adjustment and bolus therapy, dexmedetomidine may not be the best agent for treating acute agitation.

CONCLUSION

In medical-surgical ICUs, dexmedetomidine may be a viable non-benzodiazepine option for patients with a need for light sedation. In cardiac surgery patients, dexmedetomidine appears to offer no advantage over propofol as the initial sedative. The role of dexmedetomidine in unique patient populations such as neurosurgical, trauma, and obstetrics is yet to be established.