US-Based Drug Cost Parameter Estimation for Economic Evaluations.

INTRODUCTION: In the United States, more than 10% of national health expenditures are for prescription drugs. Assessing drug costs in US economic evaluation studies is not consistent, as the true acquisition cost of a drug is not known by decision modelers. Current US practice focuses on identifying one reasonable drug cost and imposing some distributional assumption to assess uncertainty. METHODS: We propose a set of Rules based on current pharmacy practice that account for the heterogeneity of drug product costs. The set of products derived from our Rules, and their associated costs, form an empirical distribution that can be used for more realistic sensitivity analyses and create transparency in drug cost parameter computation. The Rules specify an algorithmic process to select clinically equivalent drug products that reduce pill burden, use an appropriate package size, and assume uniform weighting of substitutable products. Three diverse examples show derived empirical distributions and are compared with previously reported cost estimates. RESULTS: The shapes of the empirical distributions among the 3 drugs differ dramatically, including multiple modes and different variation. Previously published estimates differed from the means of the empirical distributions. Published ranges for sensitivity analyses did not cover the ranges of the empirical distributions. In one example using lisinopril, the empirical mean cost of substitutable products was $444 (range = $23-$953) as compared with a published estimate of $305 (range = $51-$523). CONCLUSIONS: Our Rules create a simple and transparent approach to creating cost estimates of drug products and assessing their variability. The approach is easily modified to include a subset of, or different weighting for, substitutable products. The derived empirical distribution is easily incorporated into 1-way or probabilistic sensitivity analyses.

[Medical mistakes due to generic substitution]. / Medicineringsfejl ved generisk substitution.

Generic substitution is a major cause of medical mistakes in the general population. Danish legislation obligates pharmacies to substitute prescribed medicine with the cheapest equivalent formulation, despite variations in product name, packaging, shape and colour. Consequently, medical mistakes occur. Scientific evidence on the consequences of generic substitution is sparse. Call upon fellow health workers to report medical mistakes to the national entities and scientific peers, in order to increase awareness and scientific evidence about the problem.

Does bargaining affect Medicare prescription drug plan reimbursements to independent pharmacies?

OBJECTIVE: To examine how pharmacy bargaining activities affect reimbursement rates in Medicare Part D prescription drug plan (PDP) contracts, controlling for pharmacy quality attributes, market structures, and area socioeconomic status. DESIGN: Cross-sectional study. SETTING: Six Medicare regions throughout the United States between October and December 2009. PARTICIPANTS: Random sample of 1,650 independent pharmacies; 321 returned surveys containing sufficient responses for analysis. INTERVENTION: Pharmacies were surveyed regarding PDP reimbursement rates, costs, and cash prices of two popular prescription drugs (atorvastatin calcium [Lipitor-Pfizer] and lisinopril, 1-month supply of a common strength), as well as pharmacy bargaining activities and quality attributes. Data also were used from the National Council for Prescription Drug Programs pharmacy database, the 2000 U. S. Census, and the 2006 Economic Census on local market structures and area socio-economic status. MAIN OUTCOME MEASURE: PDP reimbursement rates. RESULTS: For the brand-name drug atorvastatin calcium, the PDP reimbursement was positively related to a pharmacy's request for a contract change (ß = 0.887, P < 0.05), whereas other bargaining activities were not significantly related to PDP reimbursement. However, for the generic drug lisinopril, no bargaining activities were found to be significantly related to the PDP reimbursement. CONCLUSION: Pharmacy request for a contract change was associated with higher reimbursement rates for the brand-name drug atorvastatin calcium in PDP contracts, after controlling for pharmacy quality attributes, local market structures, and area socioeconomic status; this finding likely applies to other brand-name drugs because of the structure of the contracts. Our results suggest that independent pharmacies are more likely to acquire higher reimbursement rates by engaging in active bargaining with third-party payers.

Controlling hypertension and hypotension immediately post stroke (CHHIPS)--a randomised controlled trial.

OBJECTIVES: To assess the effects of acute pressor and depressor blood pressure (BP) manipulation on 2-week death and dependency following acute stroke and investigate the safety and efficacy of such treatments. DESIGN: A multicentre, prospective, randomised, double-blind, placebo-controlled titrated-dose trial. SETTING: Five hospitals in England. PARTICIPANTS: Patients over 18 years admitted to hospital with a clinical diagnosis of suspected stroke and either (1) symptom onset < 36 hours and hypertension, defined as systolic BP (SBP) < 160 mmHg (depressor arm), or (2) symptom onset < 12 hours and hypotension, defined as SBP < or = 140 mmHg (pressor arm). INTERVENTIONS: Patients were allocated to either the pressor or the depressor arm depending on blood pressure at randomisation. The ratio of allocation to active intervention versus matched placebo was 2:1 for the depressor arm and 1:1 for the pressor arm. MAIN OUTCOME MEASURES: The primary end point was death and dependency at 2 weeks, with dependency defined as a modified Rankin score < 3. Secondary end points were the safety of acute pressor (0-12 hours post stroke) and depressor (0-36 hours post stroke) BP manipulation in stroke patients; whether effects of BP reduction are influenced by stroke type (ischaemic versus haemorrhagic); whether alternative routes for administration of antihypertensive therapy (including sublingual and intravenous) are effective in dysphagic stroke patients; whether effects of BP manipulation are influenced by the time to treatment; and the short- and medium-term cost-effectiveness of such therapy in the acute post-stroke period on subsequent disability or death. RESULTS: 180 patients were recruited over the 36-month trial period, 179 in the depressor arm and one in the pressor arm (who received placebo). No significant difference was found in death or dependency at 2 weeks between those receiving active depressor treatment with lisinopril or labetalol and those receiving placebo, although numbers recruited to the trial were lower than projected. Active treatment was not associated with an increase in early neurological deterioration despite significantly greater reductions in BP at 24 hours and 2 weeks with active therapy compared with placebo. Active treatment was generally well tolerated and treatment discontinuation rates were similar in active and placebo groups. Survival analysis showed that the active treatment group had a lower mortality at 3 months than the placebo group (p = 0.05). The pressor arm was closed early because of problems with recruitment, so no conclusions can be drawn regarding this therapy. CONCLUSIONS: Oral and sublingual lisinopril and oral and intravenous labetalol are effective BP-lowering agents in acute cerebral infarction and haemorrhage and do not increase the likelihood of early neurological deterioration. The study was not sufficiently powered to detect a difference in disability or death at 2 weeks. However, the 3-month difference in mortality in favour of active treatment is of interest, although care must be taken in interpretation of the results. Further work is needed to confirm this and to assess whether there are differences in the effectiveness of labetalol compared with lisinopril in terms of reducing death or dependency after acute stroke, and whether the introduction of treatment post stroke earlier than was achieved here would be of greater benefit.

Cost-effectiveness of chlorthalidone, amlodipine, and lisinopril as first-step treatment for patients with hypertension: an analysis of the Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT).

OBJECTIVE: To evaluate the cost-effectiveness of first-line treatments for hypertension. BACKGROUND: The Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT) found that first-line treatment with lisinopril or amlodipine was not significantly superior to chlorthalidone in terms of the primary endpoint, so differences in costs may be critical for optimizing decision-making. METHODS: Cost-effectiveness analysis was performed using bootstrap resampling to evaluate uncertainty. RESULTS: Over a patient's lifetime, chlorthalidone was always least expensive (mean $4,802 less than amlodipine, $3,700 less than lisinopril). Amlodipine provided more life-years (LYs) than chlorthalidone in 84% of bootstrap samples (mean 37 days) at an incremental cost-effectiveness ratio of $48,400 per LY gained. Lisinopril provided fewer LYs than chlorthalidone in 55% of bootstrap samples (mean 7-day loss) despite a higher cost. At a threshold of $50,000 per LY gained, amlodipine was preferred in 50%, chlorthalidone in 40%, and lisinopril in 10% of bootstrap samples, but these findings were highly sensitive to the cost of amlodipine and the cost-effectiveness threshold chosen. Incorporating quality of life did not appreciably alter the results. Overall, no reasonable combination of assumptions led to 1 treatment being preferred in over 90% of bootstrap samples. CONCLUSIONS: Initial treatment with chlorthalidone is less expensive than lisinopril or amlodipine, but amlodipine provided a nonsignificantly greater survival benefit and may be a cost-effective alternative. A randomized trial with power to exclude "clinically important" differences in survival will often have inadequate power to determine the most cost-effective treatment.

[Combined therapy with amlodipin and lisinopril in arterial hypertension: efficacy of a low-dose combination].

AIM: To assess antihypertensive efficacy of a low-dose combination of amlodipin with lisinopril in the treatment of patients with arterial hypertension (AH) of the second degree. MATERIAL AND METHODS: A total of 42 patients with the second degree of AH (16 males, 26 females, mean age 55-9 +/- 1.9 years) entered an open, comparative and controlled trial. They were divided into three groups by the treatment. Group 1 (n = 14) received amlodipin (normodipin, Gedeon Richter) monotherapy in a mean dose 8.9 +/- 0.6 mg/day, group 2 (n = 12) - lisinopril (diroton, Gedeon Richter) in a mean dose 17.5 +/- 1.4 mg/day, group 3 (n = 16) was given combined therapy with amlodipin+lisinopril in a dose 6.8 +/- 0.7 and 8.7 +/- 0.6 mg/day, respectively. The drugs were given for 12 weeks. The efficacy of the treatment was assessed by the results of 24-h monitoring of blood pressure, echocardiography, endothelium-related vasodilatation of the brachial artery (ERVD), dopplerographic investigation of circulation in the middle cerebral artery (MCA), heart rate and cost-effect estimation. RESULTS: Combined low-dose treatment with amlodipin and lisinopril for 12 weeks allowed achievement of target blood pressure in more patients and lower systolic and diastolic blood pressure than monotherapy with each of the drugs. There was also a positive effect on E/A index, ERVD, MCA circulation. CONCLUSION: Low-dose combined treatment with lisinopril and amlodipin is more effective and cost-efficient. Moreover, lisinopril addition to amlodipin corrects side effects of amlodipin on central nervous system.

High- versus low-dose angiotensin converting enzyme inhibitor therapy in the treatment of heart failure: an economic analysis of the Assessment of Treatment with Lisinopril and Survival (ATLAS) trial.

BACKGROUND: Angiotensin-converting enzyme (ACE) inhibitors reduce heart failure death and hospitalization. Prescribed doses often are lower than randomized clinical trial (RCT) targets and practice guideline recommendations. OBJECTIVE: To assess the cost-effectiveness of high- versus low-dose ACE inhibitor therapy in the ATLAS trial. STUDY DESIGN: A 19-nation RCT of high-dose (32.5-35.0 mg/day) versus low-dose (2.5-5.0 mg/day) lisinopril in 3164 patients with class II-IV heart failure and left ventricular ejection fraction < or = 30%. METHODS: Data on clinical outcomes and major cost events (hospitalizations and drug utilization) were collected prospectively. Hospital costs were estimated using Medicare and representative managed care diagnosis-related group reimbursement rates. ACE inhibitor drug costs were estimated using US average wholesale prices. Costs were discounted at 3% annually. RESULTS: Patients in the high-dose lisinopril group had fewer hospitalizations (1.98 vs 2.22, P = .014) and hospital days (18.28 vs 22.22, P = .002), especially heart failure hospitalizations (0.64 vs 0.80, P = .006) and heart failure hospital days (6.02 vs 7.45, P = .028) compared with the low-dose group. The high-dose lisinopril group also had lower heart failure hospital costs (dollars 5114 vs dollars 6361, P = .006) but higher ACE inhibitor drug costs (dollars 1368 vs dollars 855, P = .0001). Total hospital and drug costs were similar between high- and low-dose lisinopril groups (mean difference dollars -875, 95% CI dollars -2613 to dollars 884). Sensitivity analyses confirmed these findings. CONCLUSIONS: Cost savings from fewer heart failure hospitalizations offset higher ACE inhibitor costs in the high-dose group. The improved clinical outcomes were achieved without increased treatment costs.

Major outcomes in high-risk hypertensive patients randomized to angiotensin-converting enzyme inhibitor or calcium channel blocker vs diuretic: The Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT).

CONTEXT: Antihypertensive therapy is well established to reduce hypertension-related morbidity and mortality, but the optimal first-step therapy is unknown. OBJECTIVE: To determine whether treatment with a calcium channel blocker or an angiotensin-converting enzyme inhibitor lowers the incidence of coronary heart disease (CHD) or other cardiovascular disease (CVD) events vs treatment with a diuretic. DESIGN: The Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT), a randomized, double-blind, active-controlled clinical trial conducted from February 1994 through March 2002. SETTING AND PARTICIPANTS: A total of 33 357 participants aged 55 years or older with hypertension and at least 1 other CHD risk factor from 623 North American centers. INTERVENTIONS: Participants were randomly assigned to receive chlorthalidone, 12.5 to 25 mg/d (n = 15 255); amlodipine, 2.5 to 10 mg/d (n = 9048); or lisinopril, 10 to 40 mg/d (n = 9054) for planned follow-up of approximately 4 to 8 years. MAIN OUTCOME MEASURES: The primary outcome was combined fatal CHD or nonfatal myocardial infarction, analyzed by intent-to-treat. Secondary outcomes were all-cause mortality, stroke, combined CHD (primary outcome, coronary revascularization, or angina with hospitalization), and combined CVD (combined CHD, stroke, treated angina without hospitalization, heart failure [HF], and peripheral arterial disease). RESULTS: Mean follow-up was 4.9 years. The primary outcome occurred in 2956 participants, with no difference between treatments. Compared with chlorthalidone (6-year rate, 11.5%), the relative risks (RRs) were 0.98 (95% CI, 0.90-1.07) for amlodipine (6-year rate, 11.3%) and 0.99 (95% CI, 0.91-1.08) for lisinopril (6-year rate, 11.4%). Likewise, all-cause mortality did not differ between groups. Five-year systolic blood pressures were significantly higher in the amlodipine (0.8 mm Hg, P =.03) and lisinopril (2 mm Hg, P<.001) groups compared with chlorthalidone, and 5-year diastolic blood pressure was significantly lower with amlodipine (0.8 mm Hg, P<.001). For amlodipine vs chlorthalidone, secondary outcomes were similar except for a higher 6-year rate of HF with amlodipine (10.2% vs 7.7%; RR, 1.38; 95% CI, 1.25-1.52). For lisinopril vs chlorthalidone, lisinopril had higher 6-year rates of combined CVD (33.3% vs 30.9%; RR, 1.10; 95% CI, 1.05-1.16); stroke (6.3% vs 5.6%; RR, 1.15; 95% CI, 1.02-1.30); and HF (8.7% vs 7.7%; RR, 1.19; 95% CI, 1.07-1.31). CONCLUSION: Thiazide-type diuretics are superior in preventing 1 or more major forms of CVD and are less expensive. They should be preferred for first-step antihypertensive therapy.

[Medicamentous kidney protection in type 2 diabetic patients--is cheaper also more economical? A model calculation for Swiss health care]. / Medikamentöse Nephroprotektion bei Typ 2-Diabetikern--ist billiger auch ökonomischer? Eine Modellrechnung für Schweizer Verhältnisse.

Impaired renal function occurs in about 50% of patients suffering from type 2 diabetes, and diabetic nephropathy has become the leading cause of endstage renal disease. Reduction of blood pressure to levels around 120/80 mmHg is one of the most effective way to slow progression of diabetic nephropathy. Recent meta-analyses, however, have emphasized on the fact that ACE inhibitors (ACEI) and non-dihydropyridine calcium channel blockers (NDHP-CCB) exert nephro-protective effects which go beyond the effect of blood pressure reduction. This has lately been confirmed by a prospective trial in comparison to the betablocker atenolol. Based on these data, demographics of the Swiss population, literature data on mortality rates of type 2 diabetics with impaired renal function and studies on true costs of antihypertensives, we calculated the costs of a longterm intervention (20 years) with antihypertensives in 3536 middle-aged Swiss patients with type 2 diabetes and macro-albuminuria whose antihypertensive regimen was based either on the ACEI lisinopril, or the ND-HP-CCB verapamil, or the betablocker atenolol. Under atenolol, acquisition costs were lowest, whereas faster loss of renal function over time increased mortality rate and thus reduced the number of patients to be treated. Nevertheless, due to the fact that patients reached uremia and had to be dialyzed, 20 years of atenolol-based regimen with costs of 316 millions of Swiss francs turned out to be much more expensive than the lisinopril- or the verapamil-based regimen with 121 and 38 millions of Swiss francs, respectively. Thus, low acquisition cost is not necessarily the only important determinant of overall costs of drug therapy.

High dose lisinopril in heart failure: economic considerations.

UNLABELLED: BACKGROUND AND OBJECTIVES. In Switzerland, heart failure (HF) is one of the ten most common causes of hospitalization in patients older than 65 and the second most common in those over 80 years. 17% of the population in Switzerland is in this age class. The expenditures associated with HF are thus considerable. High doses of the angiotensin-converting enzyme (ACE) inhibitor lisinopril in patients with heart failure have been shown to significantly reduce the risk of death or hospitalization for heart failure and for any reason. The objective of the present study was to analyze the economic implications of using high doses of lisinopril in the Swiss health care system setting, both from the societal perspective and from that of the Swiss health insurers. PATIENTS AND METHODS: Using published data from the ATLAS Trial, we computed the monthly probability of death and of hospital admission for heart failure, ischemic events, other cardiovascular causes and any reason per patient for both arms of the trial. Swiss resource use patterns and Swiss unit costs were used to calculate expected monthly expenditures per patient from the third party payer perspective and from the societal viewpoint. Extensive sensitivity analyses were performed to test the robustness of our results. RESULTS: Expected monthly expenditures from the third party payer perspective are 347 Euro per patient in the low dose group and 319 Euro in the high dose group. This represents expected savings of 28 Euro per patient monthly. Because the public sector pays more than 50% of hospital costs, the savings from the societal viewpoint are greater. Expected monthly costs from the societal perspective are 762 Euro in the low dose group and 670 Euro in the high dose group per patient. This results in expected monthly savings of 92 Euro. Sensitivity analysis shows that the use of high doses of ACE inhibitor lisinopril does not result in higher health care expenditures for the whole system or even savings through a wide variety of practice patterns and unit costs. CONCLUSIONS: Based on the results of the ATLAS study, high doses of lisinopril are associated with a reduction in the number of hospitalizations for HF and for any reason and with a statistically non-significant reduction in mortality. The additional expenditures incurred because of prescription of high doses are offset by the savings in hospital costs. These are important considerations, given the increasing number of people aged 65 and older in Switzerland, and the prevalence of heart failure in this age group.

Low doses vs. high doses of the angiotensin converting-enzyme inhibitor lisinopril in chronic heart failure: a cost-effectiveness analysis based on the Assessment of Treatment with Lisinopril and Survival (ATLAS) study. The ATLAS Study Group.

OBJECTIVE: A cost-effectiveness analysis of high and low doses of the angiotensin-converting enzyme (ACE) inhibitor lisinopril in the treatment of chronic heart failure. METHODS: A cost-effectiveness analysis using data from a randomized controlled trial, ATLAS, where 3164 patients with chronic heart failure were allocated to a high-dose (daily target dose 32.5-35 mg) or low-dose strategy (daily target dose 2.5-5.0 mg) of lisinopril. Differential costs were based on resource use data collected in the trial costed using UK unit costs. Cost-effectiveness analysis related differential costs to differential life-years during a 4-year trial follow-up. RESULTS: The mean total number of hospital in-patient days per patient was 18. 5 in the high dose group and 22.5 in the low dose group. Over the whole duration of the trial, the mean (S.D.) daily dose of lisinopril in the high-dose group was 22.5 mg (15.7 mg) compared to 3.2 mg (2.5 mg) in the low-dose group. The mean difference in cost per patient was pound sterling 397 lower in the high-dose group [95% CI (high-dose-low-dose) - pound sterling 1263 to pound sterling 436]. Mean life-years per patient were 0.085 years higher in the high-dose group [95% CI (high-dose-low-dose) -0.0074 to 0.1706). Based on mean costs and life-years, high-dose therapy dominates low-dose (less costly and more effective). Allowing for uncertainty in mean costs and life-years, the probability of high-dose therapy being less costly than low dose was 82%. If a decision maker is willing to pay at least pound sterling 3600 per life-year gained, the probability of high-dose being more cost-effective was 92%. CONCLUSIONS: The ATLAS Study showed that the treatment of heart failure with high-doses of lisinopril has a high probability of being more cost-effective than low-dose therapy.

Cost-effectiveness analysis of early lisinopril use in patients with acute myocardial infarction. Results from GISSI-3 trial.

The cost effectiveness of early treatment with lisinopril in acute myocardial infarction (MI) was estimated using survival and cost data gathered prospectively during the hospitalisation of the overall population of patients enrolled in the third study of the Gruppo Italiano per lo Studio della Sopravvivenza nell'Infarto (GISSI-3), which assessed the efficacy of early (within 24 hours) treatment with an angiotensin-converting enzyme (ACE) inhibitor (lisinopril) for 6 weeks in a group of 19,394 relatively unselected patients with acute MI. A statistically significant reduction in 6-week mortality was achieved among patients treated with lisinopril when compared with patients allocated to the control group (absolute reduction in mortality: 7.5 +/- 3.6 lives saved per 1000 treated patients). The comparative cost-effectiveness ratio for the use of lisinopril, expressed as cost per additional survivor among patients randomised to receive lisinopril, was $US2080 per life saved (1993 values). The sensitivity analysis conducted to examine the effects of varying the estimated absolute reduction in mortality throughout its 95% confidence interval, which ranged from 14.6 to 0.4 lives saved per 1000 treated patients, showed that the cost-effectiveness ratios consequently vary from $US1121 to $US40,910 per life saved. The cost effectiveness of early treatment with lisinopril of a relatively unselected population of patients with acute MI compares very favourably with that of other therapies judged to be worthwhile by the medical community.

Lisinopril. A review of its pharmacology and clinical efficacy in elderly patients.

Lisinopril, the lysine analogue of enalaprilat, is a long-acting angiotensin converting enzyme (ACE) inhibitor which is administered once daily by mouth. The efficacy of lisinopril in reducing blood pressure is well established in younger populations, and many trials now show it to be effective in lowering blood pressure in elderly patients with hypertension. In comparative and non-comparative clinical trials, 68.2 to 89.1% of elderly patients responded (diastolic pressure < or = 90 mm Hg) to > or = 8 weeks' lisinopril treatment. Age-related differences in antihypertensive efficacy do not appear to be clinically significant, and dosages effective in elderly patients tend to range from 2.5 to 40 mg/day. Dosages usually need to be lower in patients with significant renal impairment. In congestive heart failure, lisinopril 2.5 to 20 mg/day increases exercise duration, improves left ventricular ejection fraction and has no significant effect on ventricular ectopic beats. It is similar in efficacy to enalapril and digoxin and similar or superior to captopril on most end-points. Data from the GISSI-3 post-myocardial infarction trial show that lisinopril reduced mortality and left ventricular dysfunction when given for 42 days starting within 24 hours of the onset of infarction symptoms. Results at 6 weeks and 6 months were similar in elderly and younger patients. Elderly patients, however, among other subgroups, exhibited a strong reduction in risk of low ejection fraction after treatment (-25.5%). Economic studies suggest that lisinopril is cost saving compared with other ACE inhibitors in some markets. When given according to the GISSI-3 protocol, lisinopril appears to be one of the less expensive of the successful ACE inhibitor regimens for acute myocardial infarction. In other trials, patients with diabetic nephropathy and hypertension improved or did not deteriorate during lisinopril treatment. Blood pressure was controlled and reductions or trends towards reductions in albuminuria were observed. These reductions were similar to those in diltiazem, nifedipine and verapamil recipients, and greater than those in patients receiving atenolol. Lisinopril appears to reduce mortality in diabetic patients after myocardial infarction and may also improve neuropathy associated with diabetes. Lisinopril is well tolerated and the profile of adverse events seen is typical of ACE inhibitors as a class. There is a tendency for more elderly than younger patients to discontinue treatment, but this trend is not clearly related to the incidence of adverse events in these age groups. Drug interactions occur with few other agents and are usually clinically significant only between lisinopril and either diuretics or lithium. Lisinopril is, thus, an effective treatment for elderly patients with hypertension, congestive heart failure and acute myocardial infarction and has shown promising benefits in patients with diabetic nephropathy.

Conversions from captopril to lisinopril at a dosage ratio of 5:1 result in comparable control of hypertension.

OBJECTIVE: To provide clinical support that conversion from captopril to lisinopril at a daily oral dosage ratio of 5:1 maintains comparable therapeutic efficacy, and to estimate retrospectively cost savings because of conversion from captopril to lisinopril therapy at the study site and with the associated overall drug conversion program instituted by Kaiser Permanente. DESIGN: An open-label, randomized, prospective, parallel study was performed in 56 patients with mild-to-moderate hypertension. In a 4-week preroandomization period, oral maintenance dosages of captopril were established. Patients then were randomly assigned either to continue taking captopril or to change to lisinopril at an initial conversion ratio of captopril 5 mg to lisinopril 1 mg. Blood pressures were evaluated 2, 4, 8, and 12 weeks postrandomization. If necessary, dosages were adjusted to maintain adequate efficacy (i.e., systolic pressure < 160 mm Hg and diastolic pressure < 90 mm Hg in the prerandomization period; diastolic pressure < 90 mm Hg postrandomization). Cost savings for the study site and to the overall program with respect to conversion from captopril were defined as the difference between the estimated drug costs and the drug costs projected if the conversion had not been made. SETTING: Woodland Hills Medical Center of the Southern California Region of Kaiser Permanente Medical Care Program. MAIN OUTCOME MEASURES: The main outcome measures were systolic and diastolic blood pressure. The measure for the retrospective cost savings analysis was estimated cost savings based on the number of prescriptions written for captopril and lisinopril from December 1988 through December 1993, and the average wholesale price. PARTICIPANTS: Members of the Kaiser Permanente Medical Care Program who were diagnosed with mild-to-moderate hypertension and whose hypertension was controlled by captopril alone. Retrospectively, mild-to-moderate hypertension would have been classified as stages 1-3, based on the current guidelines of the Fifth Report of the Joint National Committee on Detection, Evaluation, and Treatment of High Blood Pressure. RESULTS: The blood pressures of patients in whom captopril therapy was switched to lisinopril therapy were maintained throughout the entire study within the defined acceptable limits of control when the conversion was initiated at a daily oral dosage ratio of 5:1. The final dosage conversion ratio was not significantly different statistically from the theoretical dosage conversion ratio of 5:1. CONCLUSIONS: The conversion from captopril (in equally divided daily doses) to lisinopril (once daily) at a dosage ratio of 5:1 maintained comparable control of mild-to-moderate hypertension with no increase in adverse effects. In addition, the cost savings associated with an overall drug conversion program were substantial, and the conversion provided a preferred once-daily dosing regimen.