Nimodipine systemic exposure and outcomes following aneurysmal subarachnoid hemorrhage: a pilot prospective observational study (ASH-1 study).

Background: Nimodipine improves outcomes following aneurysmal subarachnoid hemorrhage (aSAH). Guidelines recommend that all patients should receive a fixed-dose nimodipine for 21 days. However, studies reported variability of nimodipine concentrations in aSAH. It is not clear if reduced systemic exposure contributes to worsening outcomes. The aim of this study was to compare nimodipine systemic exposure in those who experienced poor outcomes to those who experienced favorable outcomes. Methods: This was a pilot prospective observational study in 30 adult patients admitted to the University of Alberta Hospital with aSAH. Data were collected from the electronic health records following enrollment. Blood samples were collected around one nimodipine 60 mg dose at a steady state, and nimodipine [total, (+)-R and (-)-S enantiomers] plasma concentrations were determined. The poor outcome was defined as a modified Rankin Scale (mRS) score at 90 days of 3-6, while the favorable outcome was an mRS score of 0-2. The correlation between nimodipine concentrations and percent changes in mean arterial pressure (MAP) before and after nimodipine administration was also determined. Furthermore, covariates potentially associated with nimodipine exposure were explored. Results: In total, 20 (69%) participants had favorable outcomes and 9 (31%) had poor outcomes. Following the exclusion of those with delayed presentation (>96 h from aSAH onset), among those presented with the World Federation of Neurological Surgeons (WFNS) grade 3-5, nimodipine median (interquartile range) area under the concentration time curve (AUC0-3h) in those with favorable outcomes were 4-fold higher than in those with poor outcomes [136 (52-192) vs. 33 (23-39) ng.h/mL, respectively, value of p = 0.2]. On the other hand, among those presented with WFNS grade 1-2, nimodipine AUC0-3h in those with favorable outcomes were significantly lower than in those with poor outcomes [30 (28-36) vs. 172 (117-308) ng.h/mL, respectively, value of p = 0.03)]. (+)-R-nimodipine AUC0-3h in those who did not develop vasospasm were 4-fold significantly higher than those who had vasospasm (value of p = 0.047). (-)-S-nimodipine was significantly correlated with percentage MAP reduction. Similar results were obtained when the whole cohort was analyzed. Conclusion: The study was the first to investigate the potential association between nimodipine exposure following oral dosing and outcomes. In addition, it suggests differential effects of nimodipine enantiomers, shedding light on the potential utility of nimodipine enantiomers. Larger studies are needed.

The impact of palliative care consults on deprescribing in palliative cancer patients.

PURPOSE: The transition from active cancer treatment to palliative care often results in a shift in drug risk-benefit assessment which requires the deprescribing of various medications. Deprescribing in palliative cancer patients can benefit patients by reducing their pill burden, decrease potential side effects, and potentially decrease healthcare costs. In addition, a change in patients' goals of care (GOC) necessitates the alteration of drug therapy which includes both deprescribing and the addition of medications intended to improve quality of life. Depending on a patient's GOC, a medication can be considered as inappropriate. OBJECTIVES: Primary: Comparison between potentially inappropriate medications (PIMs) prior to the palliative care consult (PCC) versus after the PCC. Secondary: Association between PIMs and GOC. METHODS: The study was a 1-year retrospective database review. The study included cancer patients seen by the PCC team at the University of Alberta Hospital. The OncPal guidelines were used to identify and determine the number of PIMs prior to the PCC and after the PCC. RESULTS: The reduction in PIMs prior to PCC versus after the PCC was statistically significant (p value < 0.001), demonstrating the PCC has a positive significant impact on deprescribing PIMs. For our secondary outcome, an overall decrease in PIMs was observed with the changes of GOC. The strength of the correlations was low (r < 0.1), and the p value was 0.056. CONCLUSION: This study shows the positive impact a PCC has on deprescribing and reveals the importance of using guidelines for deprescribing in palliative cancer patients.

Cytochrome P450 3A and P-glycoprotein drug-drug interactions with voclosporin.

AIMS: Voclosporin is a novel calcineurin inhibitor intended for prevention of organ graft rejection and treatment of lupus nephritis. Pharmacokinetic drug interactions between voclosporin and a CYP3A inhibitor, inducer and substrate and a P-glycoprotein inhibitor and substrate were evaluated. METHODS: Voclosporin 0.4 mg kg(-1) was administered to 24 subjects in each of five studies, as follows: every 12 h (Q12H) alone and concomitantly with ketoconazole 400 mg once daily (QD); single dose before and single dose after rifampin 600 mg QD; Q12H where midazolam 7.5 mg was administered as a single dose alone before voclosporin and with last the dose of voclosporin; Q12H alone and concomitantly with verapamil 80 mg every 8 h; and Q12H with digoxin 0.25 mg QD. The noncompartmental pharmacokinetic parameters maximal concentration (Cmax ) and area under the concentration-time curve (AUC) were obtained, and geometric least squares mean ratios and 90% confidence intervals were evaluated. RESULTS: Ketoconazole increased voclosporin Cmax (6.4-fold) and AUC (18-fold); rifampin reduced voclosporin AUC (0.9-fold); voclosporin did not change exposure of midazolam or α-hydroxy-midazolam; verapamil increased voclosporin Cmax (2.1-fold) and AUC (2.7-fold); and voclosporin increased digoxin Cmax (0.5-fold), AUC (0.25-fold) and urinary excretion (0.2-fold). CONCLUSIONS: Administration of voclosporin concomitantly with strong inhibitors and inducers of CYP3A resulted in increased and decreased exposures, respectively, and should be considered contraindicated. Drug-drug interactions involving voclosporin and CYP3A substrates are not expected. Administration of voclosporin concomitantly with inhibitors and substrates of P-glycoprotein resulted in increased voclosporin and substrate exposures, respectively. Appropriate concentration and safety monitoring is recommended with co-administration of voclosporin and P-glycoprotein substrates and inhibitors.

Voclosporin food effect and single oral ascending dose pharmacokinetic and pharmacodynamic studies in healthy human subjects.

Voclosporin (VCS) is a novel calcineurin (CN) inhibitor intended for prevention of organ graft rejection and treatment of lupus nephritis. These studies evaluated the single ascending dose pharmacokinetics (PK) and pharmacodynamics (PD, CN activity) of VCS and the effect of food. VCS was administered orally in single doses of 0.25 through 4.5 mg/kg in 62 subjects in the single ascending dose study and as a single oral 1.5 mg/kg dose to 18 subjects after fasting, consumption of a low-fat and high-fat meal. Non-compartmental PK, PD, and PKPD correlation were evaluated. Following single oral doses, systemic exposure increased in a linear manner and demonstrated 1:1 dose-proportional, first-order linear PK above 1.5 mg/kg. VCS inhibited CN activity in a dose-related fashion with maximal inhibition peaking at 3.0 mg/kg. PKPD correlation indicated an EC50 of 78.3 ± 6.8 ng/mL. Administration of VCS with a low-fat and high-fat meal decreased C(max) by 29% and 53%, respectively, and AUC(inf) by 15% and 25%, respectively. Following ascending single doses of VCS, exposure increased in a linear fashion. A food effect on exposure was demonstrated, with a more pronounced effect following a high-fat meal. VCS concentrations were also found to correlate with CN activity.

The effect of infliximab on hepatic cytochrome P450 and pharmacokinetics of verapamil in rats with pre-adjuvant arthritis: a drug-disease and drug-drug interaction.

Inflammatory conditions result in increased concentration but reduced potency of some cardiovascular drugs. This is associated with increased levels of pro-inflammatory mediators. Infliximab reduces pro-inflammatory mediators and reverses the diminishing effect of inflammation on response in the rat. We suggested that infliximab treatment would also reverse the effects of inflammation on drug metabolism and clearance. We examined hepatic cytochrome P450 content and the pharmacokinetics of verapamil in pre-adjuvant arthritic rats treated with infliximab. Pre-adjuvant arthritis was induced in male Sprague-Dawley rats with a tail base injection of Mycobacterium butyricum. Animals were monitored for symptoms of arthritis, serum nitrite and C-reactive protein. On day 6, rats were administered with single s.c. doses of infliximab (10 mg/kg). On day 14, a single i.v. dose of racemic verapamil (2 mg/kg) was administered, and S- and R-verapamil concentrations were determined by high performance liquid chromatography. Hepatic cytochrome P450 content and verapamil protein binding were also measured. Serum nitrite levels were significantly elevated in pre-adjuvant arthritis. Infliximab did not affect mean nitrite concentrations but there was a significant correlation between nitrite and S-verapamil concentrations as well as cytochrome P450, CYP3A, and CYP1A contents. Infliximab increased cytochrome P450 enzymes content that had been diminished by pre-adjuvant arthritis but had no significant effect on verapamil protein binding. Infliximab partially restores hepatic cytochrome P450 enzyme contents. The effect of infliximab on the mean verapamil clearance was not significantly affected due, likely, to the lack of effect on plasma protein binding.

Influence of controlled rheumatoid arthritis on the action and disposition of verapamil: focus on infliximab.

Active rheumatoid arthritis (RA), obesity, and old age are associated with reduced responsiveness to the calcium channel antagonist verapamil despite increased drug concentrations. The diminishing effect appears to be associated with the severity of inflammation. We examined pharmacodynamics and pharmacokinetics of verapamil in patients with controlled RA. Volunteers included RA patients in remission: 12 on infliximab, 8 on other antirheumatic therapy, and 12 healthy subjects. Verapamil plasma concentrations and selected inflammatory mediators as well as blood pressure and electrocardiographic parameters were recorded after a single 80-mg dose of verapamil. Inflammatory mediators were all below what is reported for active RA, confirming that RA was controlled. The tumor necrosis factor-alpha concentration, however, was significantly higher in the infliximab group compared with other groups and the literature value for active RA. No significant difference was observed between groups in terms of percentage prolongation of PR interval despite a trend toward a lower response in the RA groups, the mean plasma concentrations, and the total and unbound area under the curve of verapamil. However, the slope of the S-verapamil concentration-effect curve was steeper for controls compared with the RA patients. Remission from active disease appears to restore plasma protein levels and hepatic drug metabolism activity in patients with RA, resulting in relatively normal verapamil pharmacokinetics.

Effect of early phase adjuvant arthritis on hepatic P450 enzymes and pharmacokinetics of verapamil: an alternative approach to the use of an animal model of inflammation for pharmacokinetic studies.

The objective of this study was to evaluate the suitability of the early phase of adjuvant arthritis (pre-AA) as a model of inflammation for pharmacokinetic studies. Pre-AA is associated with little or no pain and discomfort as compared with fully developed adjuvant arthritis. Pre-AA was induced in male Sprague-Dawley rats with a tail base injection of Mycobacterium butyricum. Animals were monitored for symptoms of arthritis and levels of the proinflammatory mediators, serum nitrite, C-reactive protein (CRP), and tumor necrosis factor alpha (TNFalpha). On day 6, rats were administered single i.v. (2 mg/kg) or oral (20 mg/kg) doses of racemic verapamil, and S- and R-verapamil concentrations were determined by high-performance liquid chromatography. Hepatic cytochrome P450 (P450) content and verapamil protein binding were also measured. All experiments were carried out in both pre-AA and control rats. Serum nitrite, CRP, and TNFalpha levels were significantly elevated in pre-AA rats while signs of pain and arthritis were absent. Pre-AA also significantly elevated plasma concentrations of S- and R-verapamil after both i.v. and oral doses, due, likely, to decreased drug clearance. This was accompanied by a significant reduction in hepatic cytochrome P450, CYP3A, and CYP1A content as well as significantly reduced verapamil free fraction in pre-AA. The early phase of AA is marked by increased proinflammatory mediators and reduced verapamil clearance, as well as decreased hepatic P450 enzymes. Hence, pre-AA is a suitable model of inflammation for pharmacokinetic studies that avoids unnecessary exposure of animals to the pain and distress of fully developed adjuvant arthritis.

Effect of cannulation surgery and restraint stress on the plasma corticosterone concentration in the rat: application of an improved corticosterone HPLC assay.

PURPOSE: Stress increases plasma corticosterone concentration in rats. We studied the time-course of plasma corticosterone post jugular vein cannulation, a potential stress producing process, and after 1 h restraint stress using an improved assay. Current HPLC methods for corticosterone analysis require long extraction times with large volumes of solvent. METHODS: Adult male, Sprague-Dawley rats were used. Tail vein blood samples were collected from uncannulated rats (n=4). Other rats were cannulated in the right jugular vein, allowed to recover overnight and assigned to days 1, 2, 3 or 4 groups (n=4-6/group). Blood was sampled before and after exposure to 1 h of restraint stress. Plasma was separated and extracted with 5 mL ethyl acetate (betamethasone as internal standard), and then the extract was washed with sodium hydroxide (0.1 M) and water. After evaporation of ethyl acetate, the residue was dissolved in mobile phase (acetonitrile-water-acetic acid-TEA, 22:78:0.1:0.03, v/v) and injected into an isocratic HPLC consisting of a 10 cm C18 column, and UV detector at 254 nm. RESULTS: The minimum quantifiable concentration was 10 ng/mL of corticosterone based on 0.5 mL plasma. The standard curve was linear over the concentration range of 10-500 ng/mL. The extraction efficiency was 84-87%. The coefficient of variation for intra-day and inter-day precision was <10% with <8% error. Plasma corticosterone before cannulation (74 +/- 17 ng/mL) and those measured daily before restraint stress were not significantly different from one day to another (day 1, 60 +/- 21; day 2, 59 +/- 39, day 3, 45 +/- 23, and day 4, 41 +/- 8 ng/mL). Exposure to restraint stress elevated corticosterone (day 1, 122 +/- 33; day 2, 82 +/- 23; day 3, 148 +/- 33; and day 4, 134 +/- 20 ng/mL). Except on day 2, all concentrations were significantly elevated as compared to the pre-stress levels. CONCLUSIONS: Corticosterone concentrations were stable after jugular vein cannulation, and were increased by restraint stress. The present assay is a more convenient method as compared to those previously reported.