Enhanced Renal Clearance in Patients With Hemorrhagic Stroke.

OBJECTIVES: To evaluate enhanced renal clearance over time in patients with aneurysmal subarachnoid hemorrhage or intracerebral hemorrhage via measured creatinine clearance and to compare measured creatinine clearance to creatinine clearance calculated by the Cockcroft-Gault equation and estimated glomerular filtration rate calculated by the Modification of Diet in Renal Diseases equation. DESIGN: Prospective, observational study. SETTING: Neurosciences ICU in a tertiary care academic medical center. PATIENTS: Study participants had an admission diagnosis of aneurysmal subarachnoid hemorrhage or intracerebral hemorrhage, an expected neurosciences ICU length of stay greater than 48 hours, no evidence of renal dysfunction (admission serum creatinine < 1.5 mg/dL), and no history of chronic kidney disease. INTERVENTIONS: Eight-hour urine collections to measure creatinine clearance were collected daily as the primary method of measuring renal function. Creatinine clearance was also calculated using the Cockcroft-Gault equation and estimated glomerular filtration rate was calculated using the Modification of Diet in Renal Disease equation. Enhanced renal clearance was defined as a measured creatinine clearance greater than the calculated creatinine clearance via Cockcroft-Gault and estimated glomerular filtration rate via Modification of Diet in Renal Disease. Augmented renal clearance was defined by a measured creatinine clearance greater than or equal to 130 mL/min/1.73 m. Relevant demographic, clinical, and outcome data were recorded. MEASUREMENTS AND MAIN RESULTS: Fifty aneurysmal subarachnoid hemorrhage patients and 30 intracerebral hemorrhage patients were enrolled, contributing 590 individual measurements. Patients with aneurysmal subarachnoid hemorrhage had a higher mean measured creatinine clearance compared with the mean calculated creatinine clearance based on the Cockcroft-Gault equation (147.9 ± 50.2 vs 109.1 ± 32.7 mL/min/1.73 m; p < 0.0001) and higher mean measured creatinine clearance compared with the mean calculated estimated glomerular filtration rate based on the Modification of Diet in Renal Disease equation (147.9 ± 50.2 vs 126.0 ± 41.9 mL/min/1.73 m; p = 0.04). Ninety-four percent of participants with aneurysmal subarachnoid hemorrhage experienced augmented renal clearance on at least 1 day. In patients with intracerebral hemorrhage, there was a higher mean measured creatinine clearance over the study period compared with the mean calculated creatinine clearance (119.5 ± 57.2 vs 77.8 ± 27.6 mL/min/1.73 m; p < 0.0001) and higher mean measured creatinine clearance compared with the mean calculated estimated glomerular filtration rate based on the Modification of Diet in Renal Disease equation (119.5 ± 57.2 vs 93.0.0 ± 32.8 mL/min/1.73 m; p = 0.02). Fifty percent of participants with intracerebral hemorrhage experienced augmented renal clearance on at least 1 day. CONCLUSIONS: A substantial group of patients with aneurysmal subarachnoid hemorrhage or intracerebral hemorrhage experienced enhanced renal clearance, which may be otherwise unknown to clinicians. Enhanced renal clearance may lead to increased renal solute elimination over what is expected, resulting in subtherapeutic renally eliminated drug concentrations. This may result in underexposure to critical medications, leading to treatment failure and other medical complications.

Vancomycin Pharmacokinetic Parameters in Patients with Hemorrhagic Stroke.

BACKGROUND: Infections are a common medical complication in hemorrhagic stroke patients, with vancomycin commonly used as empiric therapy. The purpose of this study was to evaluate the pharmacokinetic parameters of vancomycin in hemorrhagic stroke patients. METHODS: This was a retrospective study of adult patients with aneurysmal subarachnoid hemorrhage (aSAH) or intracerebral hemorrhage (ICH) admitted between May 2010 and February 2015 who received vancomycin. Predicted pharmacokinetic parameters based on population data were compared with calculated pharmacokinetic parameters based on serum trough concentrations. RESULTS: Eighty aSAH patients and 66 ICH patients met inclusion criteria. In the aSAH group, the mean dosing regimen was 17.6 ± 4 mg/kg every 12 (8-12) h. The mean measured trough concentration was lower than the predicted trough concentration (9.9 ± 4.1 vs. 19 ± 8.7 µg/mL; p < 0.001). The mean calculated elimination rate constant was higher than the predicted value (0.135 ± 0.04 vs. 0.092 ± 0.03 h(-1); p < 0.001), and the mean calculated half-life was lower than predicted (5.7 ± 1.8 vs. 8.3 ± 2.9 h; p < 0.001). In the ICH group, the mean dosing regimen was 15.9 ± 4.3 mg/kg every 12 (8-12) h. Similarly, the mean measured trough concentration was lower than the predicted trough concentration (10.7 ± 4.6 vs. 17.5 ± 8.5 µg/mL; p < 0.001). The mean calculated elimination rate constant was higher than the predicted value (0.106 ± 0.03 vs. 0.079 ± 0.02 h(-1); p < 0.001), and the mean calculated half-life was lower than predicted (7.2 ± 2.3 vs. 9.6 ± 3.2 h; p < 0.001). CONCLUSIONS: Patients with hemorrhagic stroke exhibited pharmacokinetic alterations favoring increased elimination of vancomycin when compared to predicted pharmacokinetic parameters based on population data. This may result in underexposure to vancomycin, leading to treatment failure and other medical complications.

A double-blind placebo-controlled trial of bupropion sustained-release for smoking cessation in schizophrenia.

The objective of this study was to examine the efficacy of bupropion for smoking cessation in patients with schizophrenia. Adults with schizophrenia who smoked more than 10 cigarettes per day and wished to try to quit smoking were recruited from community mental health centers, enrolled in a 12-week group cognitive behavioral therapy intervention, and randomly assigned to receive either bupropion sustained-release 300 mg/d or identical placebo. Fifty-three adults, 25 on bupropion and 28 on placebo, were randomized, completed at least 1 postbaseline assessment and were included in the analysis. The primary outcome measures were 7-day point prevalence abstinence in the week after the quit date (week 4) and at the end of the intervention (week 12). Subjects in the bupropion group were significantly more likely to be abstinent for the week after the quit date (36% [9/25] vs. 7% [2/28], P = 0.016) and at end of the intervention (16% [4/25] vs. 0%, P = 0.043). Subjects in the bupropion group also had a higher rate of 4-week continuous abstinence (weeks 8-12) (16% [4/25] vs. 0%, P = 0.043) and a longer duration of abstinence (4.2 [3.2] weeks vs. 1.8 [0.96] weeks, t = 2.30, P = 0.037). The effect of bupropion did not persist after discontinuation of treatment. Subjects in the bupropion group had no worsening of clinical symptoms and had a trend toward improvement in depressive and negative symptoms. We conclude that bupropion does not worsen clinical symptoms of schizophrenia and is modestly effective for smoking cessation in patients with schizophrenia. The relapse rate is high after treatment discontinuation.

Two-year follow-up of a smoking cessation trial in patients with schizophrenia: increased rates of smoking cessation and reduction.

BACKGROUND: Long-term success rates of smoking cessation programs for patients with schizophrenia are unknown. This study, conducted between June 2001 and November 2002, evaluated the rate of smoking cessation and reduction in patients with schizophrenia (DSM-IV) 2 years after they had participated in a smoking cessation study in order to determine whether subjects who significantly reduced smoking during the original trial resumed their previous level of smoking at 2 years. METHOD: Two years following a double-blind placebo-controlled trial of bupropion sustained release, 150 mg/day, added to cognitive-behavioral therapy for smoking cessation in patients with schizophrenia, subjects were interviewed, medical charts were reviewed, and carbon monoxide in expired air was measured. RESULTS: Seventeen of 18 subjects completed the follow-up assessment. More subjects were abstinent (22% [N = 4]) at the 2-year follow-up than were abstinent at the end of the trial (6% [N = 1]). Subjects who achieved significant smoking reduction during the trial were more likely to be abstinent at 2 years (4/7) than those who did not significantly reduce smoking during the trial (0/11) (chi(2) = 8.1, p <.005). Most subjects who achieved > or = 50% reduction in smoking at the end of the trial maintained at least that level of reduction at 2 years. Smoking reduction during the treatment intervention was correlated with smoking reduction at follow-up (r = 0.60, p =.01). CONCLUSION: The results from this naturalistic study suggest that behavior changes achieved in smoking cessation programs for patients with schizophrenia may be durable and may predict future smoking behavior. We conclude that further investigation into the relationship between smoking reduction and future smoking cessation in special populations is indicated.