Use of specific anti-Xa levels in acute kidney injury to transition patients from oral factor Xa inhibitors to i.v. heparin infusion.

PURPOSE: This case series presents 3 patients with acute kidney injury taking apixaban or rivaroxaban and transitioning to a heparin infusion. SUMMARY: Case 1 was a 78-year-old man admitted with respiratory failure, acute decompensated heart failure, and acute kidney injury. He was taking apixaban for atrial flutter. He was transitioned to an i.v. heparin infusion and had 2 consecutive heparin antifactor-Xa levels greater than 2 units/mL. Heparin was held and resumed about 36 hours later when the apixaban anti-Xa level was less than 50 ng/mL. Case 2 was a 55-year-old man admitted with acute kidney injury, taking apixaban for a recent deep vein thrombosis. Apixaban anti-Xa levels were monitored and i.v. heparin was initiated when the level was less than 100 ng/mL, about 56 hours after the last apixaban dose. Case 3 was a 64-year-old woman admitted with sepsis and acute kidney injury taking rivaroxaban for pulmonary embolism, which occurred 2 weeks prior to admission. Rivaroxaban anti-Xa levels were monitored and i.v. heparin was initiated about 36 hours after the last dose when the level was less than 100 ng/mL. The management strategy did not lead to any thrombotic outcomes; however, 1 patient experienced bleeding. CONCLUSION: Specific anti-Xa levels for rivaroxaban and apixaban appeared to be helpful in the transition of 3 patients to unfractionated heparin infusions in the setting of acute kidney injury. These levels provided enhanced, individualized care and likely helped avoid over and under anticoagulation.

Vaccinations in asplenic adults.

PURPOSE: The recommended immunizations for adult asplenic patients are reviewed. SUMMARY: Patients without a spleen are at risk of developing overwhelming postsplenectomy infections due to encapsulated organisms, mainly pneumococcal, meningococcal, and Haemophilus influenzae type b (Hib). Due to the high mortality rates associated with these infections, vaccinations are recommended as a preventive measure. It is challenging to ensure optimal immunizations in these high-risk patients due to the number of recommended vaccines, the availability of multiple formulations, and the inability to administer specific formulations at the same time, as well as differences in subsequent vaccine administration schedules. Pharmacists play a key role in recommending specific vaccines and timing for these patients in order to achieve the most robust immune response. This article reviews the specific recommendations for pneumococcal, meningococcal, Hib, and influenza vaccinations in asplenic patients. CONCLUSION: In order to prevent potentially life-threatening infections, asplenic individuals should be vaccinated against S. pneumoniae, N. meningitidis, Hib, and influenza. The optimal timing of vaccination in relation to splenectomy depends on the nature of the splenectomy.

High-dose argatroban for treatment of heparin-induced thrombocytopenia with thrombosis: a case report and review of laboratory considerations.

PURPOSE: A case report describing high-dose argatroban for the treatment of heparin-induced thrombocytopenia (HIT) with thrombosis and associated considerations in interpreting laboratory monitoring data are presented. SUMMARY: A 51-year-old woman with an extensive history of coronary artery disease arrived at the emergency department with complaints of chest pain. The patient was admitted, and coronary artery bypass graft surgery was ultimately performed. The patient had a baseline platelet count of 177,000 cells/µL. During hospitalization, the patient received heparin, and her platelet count dropped to 12,000 cells/µL 13 days after the initiation of heparin. The patient developed swelling around a peripherally inserted central catheter and later developed deep vein thrombosis. An argatroban infusion of 2 µg/kg/min was initiated, with a target activated partial thromboplastin time (aPTT) of 40-80 seconds. After 5 days of therapy, the patient had increased swelling in her right arm and an aPTT of 56 seconds. Her goal aPTT was subsequently increased. Six days later, the patient developed a left-lower-extremity DVT despite aPTTs within the goal range. A new aPTT target of >75 seconds was set. The infusion rate was increased to 15.5 µg/kg/min to attain the target aPTT. Results of an in vitro test led to an alternative interpretation of aPTT and International Normalized Ratio values that aided in the monitoring of argatroban during the high-dose infusion. CONCLUSION: A patient with HIT with thrombosis was successfully treated with unusually high dosages of argatroban and may have had serum argatroban concentrations exceeding what has commonly been thought to be the therapeutic range.

Susceptibility of Staphylococcus aureus to vancomycin: analysis of minimum inhibitory concentrations in two tertiary care hospitals in eastern South Dakota.

BACKGROUND: Vancomycin has been considered the accepted standard of therapy for methicillin-resistant Staphylococcus aureus (MRSA) and is commonly used as an alternative for methicillin-suceptible Staphylococcus aureus (MSSA) in cases of allergy or intolerance to other agents. MRSA strains exhibiting elevated vancomycin MICs (minimum inhibitory concentration) within the susceptible range have been associated with increased treatment failure and mortality. The aim of our study was to evaluate for evidence of elevated vancomycin MICs among S. aureus isolates associated with pneumonia or skin/soft tissue infection (SSTI) in our adult inpatient population. METHODS: S. aureus vancomycin MIC data was retrospectively reviewed for the period of July 1, 2008, to December 31, 2008. Adult inpatients were included in our analysis if treatment was initiated with an anti-staphylococcal agent for at least 48 hours for either pneumonia or SSTI. Patient demographics and susceptibilities to non-vancomycin antistaphylococcal agents were collected. RESULTS: A total of 272 patients met inclusion criteria. Only three patients were infected with S. aureus isolates found to have elevated vancomycin MICs within the susceptible range (> 1 mcg/mL to < or = 2 mcg/mL). This included two patients with pneumonia (one MRSA, one MSSA) and one patient with SSTI caused by MRSA. All S. aureus isolates were susceptible to linezolid and trimethoprim-sulfamethoxazole (TMP-SMX), with tetracycline susceptibility exceeding 90 percent in all subsets. CONCLUSIONS: Elevated vancomycin MICs were uncommon in our sample among adult inpatients with pneumonia or SSTI caused by S. aureus. Vancomycin appears to remain a viable option for the treatment of these infections in our patient population.

Potential interaction between valproic acid and doripenem.

A potential interaction between valproate (VPA) and doripenem leading to decreased valproic acid concentrations in two patients is described. In the first patient case, a 54-year-old female presented to the emergency department following a seizure episode after stopping her medications a few days prior. She was given a 1500 mg (23 mg/kg) intravenous (IV) bolus dose of valproate and restarted on her home regimen of divalproex sodium 750 mg daily which quickly resulted in valproic acid blood concentrations within the reference range. The patient was later started on doripenem 500 mg IV every 8 hours and subsequent valproic acid concentrations decreased by 62%. The second patient was a 54-year-old female transferred from an outlying facility following a motor vehicle accident. The patient was receiving valproate 1250 mg IV every 8 hours for seizure prophylaxis following a traumatic brain injury. She developed pneumonia and was started on doripenem 500mg IV every 8 hours. Valproic acid concentrations decreased by 69% within two days. This case report describes two patients receiving concomitant valproate and doripenem resulting in a 62% and 69% reduction in valproic acid concentration.

Withdrawal symptoms after gabapentin discontinuation.

PURPOSE: A case of apparent gabapentin withdrawal symptoms after discontinuation of gabapentin therapy is reported. SUMMARY: A 53-year-old woman had coffee ground emesis, a two-day history of black tarry stools, and abdominal pain. The patient did have an elevated ethanol concentration (323 mg/dL), with the last reported ingestion of ethanol about 12 hours before admission. Her medical history included liver cirrhosis secondary to ethanol abuse, ascites, portal hypertension, esophageal varices (with previous band ligation three weeks prior), anemia, gastroesophageal reflux disease, neuropathic pain, and depression. Her home medications included spironolactone, nadolol, lactulose, ursodiol, ferrous sulfate, omeprazole, gabapentin, citalopram, and trazodone. She was admitted to the intensive care unit, and upper gastrointestinal endoscopy was performed, with 12 band ligations applied. After the procedure, she ingested nothing orally, including home medications, for the first two days. On day 3 of hospitalization, she developed restlessness, disorientation, confusion, agitation, and anxiety. She was presumed to be suffering from ethanol withdrawal and was treated with benzodiazepines but had no improvement in symptoms. During days 4 and 5, the patient became increasingly confused, agitated, and anxious, with complaints of headache, light sensitivity, and increasing nervousness. On day 5, gabapentin was reinitiated, and the patient's confusion and agitation improved that evening. The next morning, the patient was calm, alert, and cooperative. Her symptoms resolved, and she was discharged on hospital day 7. CONCLUSION: A patient developed apparent withdrawal symptoms beginning two days after gabapentin therapy was discontinued. The symptoms were unresponsive to treatment with benzodiazepines but completely resolved with the reinitiation of gabapentin therapy.