Pharmacoeconomic evaluation of a pharmacist-managed hypertension clinic

STUDY OBJECTIVE

To measure clinical, economic, and humanistic outcomes associated with a pharmacist-managed hypertension clinic compared with physician-managed clinics.

DESIGN

Prospective, randomized, comparative study.

SETTING

Managed care organization.

PATIENTS

A total of 330 patients with mild-to-moderate essential hypertension.

INTERVENTION

Hypertension care provided by either the pharmacist-managed hypertension clinic or physician-managed general medical clinics.

MEASUREMENTS AND MAIN RESULTS

Baseline and 6-month evaluations consisted of systolic and diastolic blood pressure measurements, a short-form health survey, and collection of health care utilization information. After treatment, blood pressure measurements were significantly lower (p<0.001) in the pharmacist-managed hypertension clinic group than in the physician-managed clinic group. Patient satisfaction was significantly higher in the hypertension clinic group. Total costs for the hypertension clinic group were not different from those of the physician-managed clinic group ($242.46 vs $233.20, p=0.71), but cost:effectiveness ratios were lower in the hypertension clinic group ($27 vs $193/mm Hg for systolic blood pressure readings, and $48 vs $151/mm Hg for diastolic blood pressure readings).

CONCLUSION

In a hypertension clinic, pharmacists can be a cost-effective alternative to physicians in management of patients, and they can improve clinical outcomes and patient satisfaction.

Cefepime: a new fourth-generation cephalosporin

The chemistry, pharmacology, antimicrobial spectrum, pharmacokinetics, clinical efficacy, adverse effects, and dosage of cefepime are reviewed. Fourth-generation cephalosporins, such as cefepime, have a quaternary nitrogen that is positively charged at the 3-position, providing the properties of a zwitterion. A 2-aminothiazolyl-acetamido group in the side chain at the 7-position with an alpha-oxyimino substitution may enhance stability against beta-lactamases by preventing the enzymes' approach to the main nucleus. Cefepime may exert its antimicrobial effect by attaching to specific penicillin-binding proteins, disrupting cell-wall synthesis. Cefepime has good activity against gram-positive organisms, such as Staphylococcus aureus, and gram-negative organisms, such as Pseudomonas aeruginosa. Cefepime is not active in vitro against Enterococcus faecalis, Clostridium difficile, and methicillin- and cefazolin-resistant Staph. aureus. Cefepime's activity against gram-negative organisms is similar to that of most third-generation cephalosporins. The agent has poor activity against Bacteroides species. The most common mechanism of resistance to cefepime is the excess production of beta-lactamases. Maximum peak plasma concentrations are two to three times higher after i.v. administration than after intramuscular administration. In healthy adults, the volume of distribution is 13-22 L and the elimination half-life is 2-2.3 hours. Clinical studies show that cefepime is as effective as cefotaxime or ceftazidime in patients with infections of the lower respiratory tract, skin and skin structures, urinary tract, or female reproductive system. Cefepime reduces fever as effectively as ceftazidime or piperacillin plus gentamicin in neutropenic patients. The most common adverse effects of cefepime are headache (2.4%), nausea (1.8%), rash (1.8%), and diarrhea (1.7%). Depending on creatinine clearance, the dosage of cefepime is 1000-2000 mg i.v. every 8-24 hours for life-threatening infections and 500-2000 mg i.v. every 12-24 hours for severe infections. Cefepime's clinical efficacy is comparable to that of ceftazidime and cefotaxime.

Pharmacokinetics of meropenem in patients with intra-abdominal infections

Noncompartmental and compartmental analyses of meropenem disposition in patients receiving 1-g intravenous intermittent infusions every 8 h were performed. Twelve patients (one woman and 11 men) participated in the meropenem pharmacokinetic analysis. Operative findings included perforated appendicitis (five patients), gangrenous appendicitis (five patients), peri-appendical abscess (one patient), and gunshot wound to the abdomen (one patient). The most common associated adverse drug reactions to meropenem were diarrhea and increased liver enzymes. The estimated noncompartmental pharmacokinetic parameters, mean +/- standard deviation, are as follows: maximum drug concentration in plasma, 47.58 +/- 17.59 micrograms/ml; half-life, 1.04 +/- 0.19 h; elimination rate constant, 0.68 +/- 0.12 h-1; area under the concentration-time curve from 0 h to infinity, 57.5 +/- 20.12 micrograms x ml/h; total plasma clearance, 315.40 +/- 71.94 ml/min; renal clearance, 136.7 +/- 89.20 ml/min; volume of distribution at steady state, 26.68 +/- 6.88 liters; and mean residence time, 1.47 +/- 0.28 h. The two-compartment model best described meropenem disposition in our patients. Our findings differed from estimates for healthy volunteers possibly because of the physiologic changes as a result of surgery. Our findings suggest that meropenem (1,000 mg) administered intravenously every 8 h provides adequate concentrations for most intra-abdominal infections.

Effect of antihypertensive formulation on health service expenditures

A major barrier to the management of hypertension is the extent to which patients comply with the treatment regimen. Herein we report the findings of a retrospective analysis designed to discern the relationship between antihypertensive formulation, regimen compliance and the utilization of health care services. Data for this analysis were derived from the state of South Carolina's Medicaid computer archive. The study population consisted of 1,000 randomly selected beneficiaries initially prescribed one of the following antihypertensive regimens as monotherapy: atenolol (daily); captopril (twice daily); oral clonidine (twice daily); transdermal clonidine (once a week); diltiazem (twice daily); enalapril (twice daily); metoprolol (twice daily); prazosin (twice daily); terazosin (daily); and verapamil-SR (daily). Multivariate regression analysis was used to determine the incremental influence of selected demographic characteristics, utilization of medical services prior to diagnosis for hypertension, initial antihypertensive medication, medication possession ratio for antihypertensive therapy, and the number of maintenance medications for disease state processes other than hypertension on post-period health care expenditure. Results indicate that patients initially prescribed antihypertensive medication requiring daily or weekly administration experience infrequent changes in their therapeutic regimen, far less use of concomitant therapy for blood pressure control, an increased utilization of antihypertensive medication, and a decrease in the use and cost of physician, hospital and laboratory services.

Cefepime clinical pharmacokinetics

Cefepime is a new parenteral cephalosporin with antimicrobial activity similar to third-generation cephalosporins. It acts against the Enterobacteriaceae family, and Pseudomonas aeruginosa, but maintains Gram-positive activity similar to that of first- or second-generation cephalosporins. Cefepime has in vitro activity against many bacterial isolates resistant to ceftazidime and cefotaxime, is stable against chromosomally mediated beta-lactamases, demonstrates lower affinity for these enzymes and shows a high resistance to enzymatic hydrolysis. Clinical uses thus far include treatment of lower respiratory tract, intra-abdominal and urinary tract infections, skin and soft tissue infections and for prophylaxis in biliary tract and prostate surgery. Pharmacokinetic studies indicate that cefepime exhibits linear pharmacokinetic behaviour. Pharmacokinetic variables are not significantly different between single- and multiple-dose administration, indicating a lack of drug accumulation in patients with normal renal function. Cefepime is not highly bound to plasma proteins, with binding values of approximately 16 to 19%. The drug is widely distributed in various biological tissues and fluids. The primary route of elimination is from the kidneys, with over 80% of the drug recovered in the urine as unchanged drug in patients with normal renal function. Total drug clearance and renal clearance are similar to creatinine clearance, and glomerular filtration is thought to be the primary mechanism of renal excretion. The elimination half-life is approximately 2 to 2.5 h in patients. Cefepime is removed by haemodialysis (over 3h) and peritoneal dialysis (over 72h) to an appreciable extent, with 40 to 68% and 26% of the drug removed, respectively. Overall, cefepime is well tolerated by patients and no significant drug interactions have been reported to date.

Effect of pharmaceutical formulation for antihypertensive therapy on health service utilization

A significant factor in the management of hypertension is the extent to which patients comply with the treatment regimen. A retrospective analysis was undertaken to determine the relationship between antihypertensive formulation, regimen compliance, and the utilization of health care services. Data for this analysis were derived from the state of South Carolina's Medicaid computer archive. The study population consisted of 1000 randomly selected patients initially prescribed one of the following antihypertensive regimens as monotherapy: atenolol once daily, captopril BID, oral clonidine BID, transdermal clonidine once weekly, diltiazem BID, enalapril BID, metoprolol BID, prazosin BID, terazosin once daily, and sustained-release verapamil once daily. Multivariate regression analysis was used to determine the incremental influence of selected demographic characteristics, use of medical services before diagnosis of hypertension, initial antihypertensive medication, medication possession ratio for antihypertensive therapy, and number of maintenance medications for diseases other than hypertension on post-period health care expenditures. The results indicated that patients initially prescribed antihypertensive medication requiring once-daily or once-weekly administration experienced an increased utilization of antihypertensive medication, needed fewer changes in their therapeutic regimen, and far less need for concomitant therapy for blood pressure control compared with those prescribed a BID regimen. Patients in the once-daily or once-weekly groups also used significantly fewer physician, hospital, and laboratory services (P < or = 0.05).

Tissue concentrations of cefepime in acute cholecystitis patients

Cefepime is a new broad-spectrum cephalosporin with activity against Staphylococcus, Streptococcus, Pseudomonas, and the Enterobacteriaceae. The purpose of this study was to measure cefepime concentrations in plasma, peritoneal fluid, bile fluid and appendix tissue in patients undergoing elective cholecystectomy. Patients were randomly assigned to receive either cefepime, 2 g intravenously in phosphate buffer (IVPB) q 12 h or gentamicin 1.5 mg/kg IVPB q 8 h plus mezlocillin 4 g IVPB q 6 h. During surgery, gall bladder tissue, plasma, peritoneal fluid, and bile fluid samples were obtained at approximately the same time. Thirty-three patients had data acceptable for analysis. Values are given as mean +/- standard deviation. The mean delta time (defined as the time between the administration of cefepime and the time the samples were obtained) was 8.58 +/- 3.53 h. The values for plasma, peritoneal fluid, bile fluid, and gall bladder tissue concentrations were 7.63 +/- 14.17 micrograms/ml, 5.66 +/- 6.80 micrograms/ml, 15.51 +/- 16.94 micrograms/ml, and 5.36 +/- 6.57 micrograms/gm, respectively. The peritoneal fluid/plasma ratio was 2.10 +/- 2.33, the bile fluid/plasma ratio was 14.44 +/- 31.99, and the gall bladder tissue/plasma ratio was 1.44 +/- 1.82. There was a significant correlation between peritoneal fluid and plasma concentration (r = 0.91, p less than 0.0005), and gall bladder tissue and plasma concentration (r = 0.90, p less than 0.0005). There was no correlation between bile fluid and plasma cefepime concentrations. The minimum inhibitory concentration (MIC) data from previous in vitro studies indicate that cefepime concentrations achieved in this patient population would be adequate against typical biliary tract pathogens.(ABSTRACT TRUNCATED AT 250 WORDS)

Pharmacokinetic population parameters for aminoglycosides in cholecystitis patients

We report the use of a new method to determine patient population pharmacokinetic parameters (nonparametric expected maximum or NPEM). Our purpose was to develop and then analyze the utility of these parameters, compared to a more traditional approach. Nineteen patients with acute cholecystitis made up the control group for defining the parameters via NPEM. The standard of practice was to use a model created from a different intraabdominal infection group (appendicitis), referred to as "surgical patient model." These two models were compared with a group of 23 patients receiving gentamicin for acute cholecystitis. We concluded that the NPEM model was superior to the surgical patient model in predicting gentamicin trough and peak levels with less bias and better precision.

Effect of health education in promoting prescription refill compliance among patients with hypertension

A multifactorial health-education program designed to enhance compliance with a once-daily regimen of atenolol was evaluated among 453 patients enrolled in health maintenance organizations (HMOs). The initiation of the 180-day study period was used to classify patients as either new or existing cases of hypertension. In turn, patients in these two categories were randomly assigned to a control or an experimental group. Patients assigned to the experimental groups received an enrollment kit upon exercising their initial prescription (new patients) or their first refill request (existing patients). The kit contained: a 30-day supply of atenolol; an educational newsletter about hypertension; information on nutrition and life-style changes; and an explanation of the intent and content of the program. Before the next scheduled prescription-refill date, each patient was contacted by telephone to inquire about his or her experience with the therapy and to stress the importance of adherence to the regimen. Each month thereafter, the newsletter and an enclosed prescription-refill reminder were mailed to each patient. The medication possession ratio, defined as the number of days' supply of atenolol obtained by a patient during the 180-day study period, was significantly (P less than or equal to 0.001) enhanced for the new and existing experimental groups relative to the control groups. Multiple regression analyses revealed that enrollment in the health-education program increased the number of days' supply of atenolol obtained by existing patients by 27 (P less than or equal to 0.001), and by new patients by 40 (P less than or equal to 0.001).

Effectiveness of the C Cap in promoting prescription refill compliance among patients with glaucoma

In an attempt to increase patient compliance with a dosing regimen, prescriptions for topical solutions of glaucoma medication were refilled using the C Cap, a memory aid designed to help patients to remember to instill the medication as prescribed. A comparison of the number of prescription refills requested by 121 patients with glaucoma showed that patients who received the C Cap requested significantly more refills in the six months after receiving the C Cap than before and requested significantly more refills than did patients who did not receive the C Cap.