Polypharmacy in chronic kidney disease: Health outcomes & pharmacy-based strategies to mitigate inappropriate polypharmacy

The rising prevalence of comorbidities in an increasingly aging population has sparked a reciprocal rise in polypharmacy. Patients with chronic kidney disease (CKD) have a greater burden of polypharmacy due to the comorbidities and complications associated with their disease. Polypharmacy in CKD patients has been linked to myriad direct and indirect costs for patients and the society at large. Pharmacists are uniquely positioned within the healthcare team to streamline polypharmacy management in the setting of CKD. In this article, we review the landscape of polypharmacy and examine its impacts through the lens of the ECHO model of Economic, Clinical, and Humanistic Outcomes. We also present strategies for healthcare teams to improve polypharmacy care through comprehensive medication management process that includes medication reconciliation during transitions of care, medication therapy management, and deprescribing. These pharmacist-led interventions have the potential to mitigate adverse outcomes associated with polypharmacy in CKD.

Evaluation of serum calcium differences in hypertensive crises and control patients: A randomly matched case-control study

The role of calcium in blood pressure has been widely studied among hypertensive patients; however, no study has explored the role of calcium in hypertensive crises. The primary objective of this study is to evaluate the differences in serum calcium levels between hypertensive crises patients and a 1:1 random matched controls (age‐, sex‐, race‐, diabetes, and body mass index matched). This study is a single‐center, retrospective, chart review, case‐control study of patients with hypertensive crises (case group) and patients without hypertensive crises (control group). Patients were included in the case group if they were 18 years of age or older with hypertensive crises and have a documented calcium level. The control group patients were required to be 18 years of age or older, have a documented calcium level, and have no diagnosis of hypertensive crises. The primary outcome of the study was to compare the mean serum calcium in patients with hypertensive crises vs patients without hypertensive crises. Five hundred and sixty‐six patients were included in the study: 283 patients in both the case group and control group. The primary outcome results showed that serum calcium concentration was not significantly different between the case group (8.99 ± 0.78 mg/dL) and control group (8.96 ± 0.75 mg/dL) (P = .606). This study found no significant difference in serum calcium levels in patients with hypertensive crises compared to a random matched control group. Larger observational or experimental studies may be useful to evaluate the effect of calcium on blood pressure in hypertensive crises.

Evaluation of serum magnesium differences in hypertensive crises and control patients: A randomly matched case-control study

Although the role of magnesium in blood pressure has been well studied among hypertensive patients, no study has explored the role of magnesium in hypertensive crises. The primary objective of this study is to evaluate the differences in serum magnesium levels between hypertensive crises patients and matched controls (age‐, sex‐, race‐, and diabetes‐matched) in a 1:1 random match. This study is a single‐center, retrospective, chart review, case‐control study of patients with hypertensive crises (case group) and patients without hypertensive crises (control group). Patients were included in the case group if they were 18 years of age or older with hypertensive crises and have a documented magnesium level. The control group patients were required to be 18 years of age or older, have no diagnosis of hypertensive crises, and have a documented magnesium level. The primary outcome of the study was to compare the mean serum magnesium in patients with hypertensive crises versus patients without hypertensive crises. Three hundred and fifty‐eight patients were included in the study: 179 patients in both the case group and control group. The primary outcome results showed that serum magnesium concentration was not significantly different between the case group (1.89 ± 0.29 mg/dl) and control group (1.90 ± 0.31 mg/dl) (p = .787). This study found no significant difference in serum magnesium levels in patients with hypertensive crises compared to a random matched control group. Larger observational or experimental studies may be useful to evaluate the effect of magnesium on blood pressure in hypertensive crises.

Concordance of Vancomycin Population-Predicted Pharmacokinetics with Patient-Specific Pharmacokinetics in Adult Hospitalized Patients: A Case Series

BACKGROUND

Vancomycin empiric therapy is commonly dosed using clinical algorithms adapted from population-predicted pharmacokinetic parameters. However, precise dosing of vancomycin can be designed using patient-specific pharmacokinetic calculations.

OBJECTIVE

The objective of this study is to assess the correlational fit between vancomycin population-predicted and patient-specific pharmacokinetic parameters [elimination rate constant (K_e) and half-life (t_1/2)] in a case series of adult hospitalized patients.

METHODS

This is a single-center case series of hospitalized adult patients who received vancomycin, had creatinine clearance calculation for derivation of population-predicted pharmacokinetic parameters, and had two vancomycin concentrations for calculation of patient-specific pharmacokinetic parameters. The primary objective of this case series is to evaluate the correlation between population-predicted and patient-specific pharmacokinetic parameters. The secondary objectives of this study are to evaluate the mean bias and precision between the population-predicted and patient-specific pharmacokinetic parameters and to assess the correlation between population-predicted and patient-specific pharmacokinetic parameters in special population subgroups (obese patients with body mass index ≥ 30 kg/m² and patients with renal dysfunction). All correlation analyses were performed on the population-predicted pharmacokinetics using diverse methods of estimating renal function (Salazar-Corcoran and Cockcroft-Gault methods using either ideal, actual, or adjusted body weights). All significance testing was set at an α of < 0.05. IBM SPSS Statistics version 25 and SAS version 9.4 were used to conduct all statistical analyses.

RESULTS

A total of 30 patients were included in the study; 33.3% (10/30) of the patients were obese and 56.7% (17/30) had renal dysfunction. In all patients in the study, the calculated population-predicted K_e and t_1/2 using all four creatinine clearance estimation methods were each significantly correlated with patient-specific K_e and t_1/2 (all Pearson correlation coefficients [r]: > + 0.7, p < 0.001). The population-predicted K_e and t_1/2 calculated using Cockcroft-Gault creatinine clearance using adjusted body weight showed the strongest association with patient-specific K_e and t_1/2. In the subgroup analyses, all the population-predicted K_e and t_1/2 using four creatinine clearance estimation methods were each significantly correlated with patient-specific K_e and t_1/2. The exception was the population-predicted t_1/2 derived from Cockcroft-Gault creatinine clearance using actual body weight that did not show a significant correlation with patient-specific t_1/2 in obese patients.

CONCLUSIONS

In this case series, population-predicted pharmacokinetic parameters were strongly correlated with patient-specific pharmacokinetic parameters. The vancomycin population-predicted pharmacokinetic formula can be used safely to predict a patient's vancomycin pharmacokinetic disposition and can be maintained as an empiric dosing strategy in various hospitalized adult patients.

Phenytoin-Induced Purple Glove Syndrome: A Case Report and Review of the Literature

OBJECTIVE

To present a case report and literature review of phenytoin-induced purple glove syndrome (PGS).

CASE SUMMARY

A 54-year-old African American male presented to our hospital's emergency department (ED) following a seizure episode, cardiac arrest, and loss of consciousness. On arrival to the ED, the patient's total phenytoin level was subtherapeutic at 4.1 mcg/mL and his corrected total phenytoin level was subtherapeutic at 5.1 mcg/mL. In the ED, the patient received a loading dose of intravenous (IV) phenytoin 1,000 mg once via the left cephalic vein, at a rate of 50 mg/min, and was admitted to the medicine service. A day following IV phenytoin administration, a nurse noticed an IV fluid infiltration on the skin tissue around the left cephalic vein. The area appeared dark blue and purple in color, swollen, erythematous, and warm to touch. An ultrasound of the left upper extremity was performed and revealed subcutaneous fluid collection without evidence of thrombosis.

DISCUSSION

The Naranjo Adverse Drug Reaction Probability Scale assigned a score of 7, indicating phenytoin as the probable cause of purple glove syndrome (PGS). The patient's PGS was managed with a combination of dry dressing material, left forearm elevation, collagenase topical cream, 0.1% IV bupivacaine, and IV fentanyl. The patient's injury was resolving at the time of discharge to a rehabilitation facility.

CONCLUSION

PGS is a rare complication of IV phenytoin therapy. The risk of PGS for this patient may have been abated by decreasing the phenytoin infusion rate from 50 mg/min to less than 25 mg/min.