Therapeutic approach to hypertension during pregnancy

QuestionQuite a few of my pregnant patients have hypertensive disorders. What is the threshold for treating hypertension during pregnancy? Which of the various antihypertensive agents are considered safe during pregnancy?AnswerPharmacologic therapy could benefit mother and baby when diastolic pressure exceeds 110 mm Hg. Preeclampsia must be followed closely. Methyldopa (eg, Aldomet) and hydralazine (eg, Apresoline) are still the drugs of choice during pregnancy, although the safety and efficacy of calcium channel blockers and Beta-blockers appear well established.

Use of calcium channel blockers in hypertension

During the past 20 years the number of subclasses of calcium channel blockers has increased from one to four. Three classes have only a single clinically approved compound: verapamil, diltiazem, and mibefradil. The fourth class, dihydropyridines, contains numerous compounds. All agents are effective in lowering blood pressure in short-term studies, and side effects that trouble the patient are infrequent. Long-term studies in hypertensive patients are limited. Short-acting agents such as nifedipine have been associated with an increased cardiovascular risk in some, but not all studies. These agents also probably create a compliance problem for hypertensive patients because of the need for multiple daily doses and their unpleasant side effects, e.g., ankle edema, palpitations, and flushing. Therefore, they are not useful or indicated for the treatment of hypertensive patients. No data have suggested that long-acting dihydropyridines or nondihydropyridine calcium channel blockers share the same fate. Indeed, several lines of evidence suggest the opposite: they have a cardioprotective effect. However, definitive information will require the completion of several long-term trials, including ALLHAT, CONVINCE, HOT, INSIGHT and NORDIL. Finally, it is important to reflect on the lessons learned from the controversy associated with the potential risks of calcium channel blockers. First, disagreements are common when one uses case-controlled studies and are reflective of the poor precision of the methods used. What is statistically relevant in one study may not hold true for another and may have no clinical relevance, particularly if the relative risk is less than 2. Investigators need to temper their enthusiasm to reflect this reality. Second, at the cutting edge of science there is probably relatively little agreement about what is correct among equally competent scientists. All have bias in their positions and should both recognize and admit so to themselves and their colleagues. Inferring that those who disagree have an unstated secondary agenda that will bring personal financial rewards or government accolades is inappropriate and counterproductive. Third, the randomized clinical trial, despite all its imperfections, is still the best tool to establish common ground on controversial issues. Finally, what may seem best from the public health perspective may not be in the best interest of the individual patient--a possibility that physicians have to constantly consider. For example, no public health benefit occurs if patients remain hypertensive because they fail to take their medications, no matter what the medication.

[Drugs used in the treatment of arterial hypertension in dialysis patients in the Piedmont. What correlations between personal and clinical data can be made from the registry data?]

The therapeutical approach to arterial hypertension in the general population is now relatively well classified, whereas it remains a controversial problem in dialytic patients. The aim of this study was to evaluate the antihypertensive drugs used in dialytic patients in Piedmont and to identify correlations with other personal and clinical data. The authors analysed the data in the Piedmont Dialysis and Transplant Register concerning new patients admitted to dialysis during the period 1990-1995 (2,664 patients at 31/12/1995) and 1,373 patients who began dialysis during the period 1990-1993. A study of the antihypertensive drugs using in single and combined therapy over the five-year period shows major variations in the 45-65 year-old age bracket (increased ACE-inhibitors in single therapy, 15.5-25.6%, increased vasodilators in combined therapy, 15.3-21%). In patients aged > or = 65 years old a slight increase was found in the use of beta-blockers in monotherapy. Antihypertensive drugs at the 1st control (1990-1995 entries) appeared to be stable over the five-year period. From the 1,373 patients who started dialysis in the period 1990-1993, with at least three subsequent controls, the authors selected those hypertensive or normotensive patients receiving ACE-inhibitor therapy (best survival in general population) and compared their survival with that of patients receiving alternative antihypertensive treatment. No significant differences were found. The stability of the antihypertensive drugs taken by these patients over the past 5 years backs the hypothesis of a greater attention paid by nephrologists to the introduction of new drugs, both because of the frequent onset of collateral effects and owing to the special pharmacokinetics present in dialytic patients.

Protocol for prospective collaborative overviews of major randomized trials of blood-pressure-lowering treatments. World Health Organization-International Society of Hypertension Blood Pressure Lowering Treatment Trialists' Collaboration

OBJECTIVE

To conduct prospectively planned overviews (meta-analyses) of the ongoing randomized trials of blood-pressure-lowering drugs. These overviews should provide reliable data about the effects of newer classes of blood-pressure-lowering drugs (such as angiotensin converting enzyme inhibitors and calcium antagonists) on major causes of cardiovascular mortality and morbidity for a variety of patient groups.

METHODS

A registry of major ongoing or planned randomized trials (with more than 1000 patient-years of follow-up for each randomized group) of blood-pressure-lowering agents has been established. The principal investigators of each of these studies have been invited to collaborate in the project and to provide, upon completion of the study, a limited data set for inclusion in the overview analyses. The principal comparisons will be of newer versus older classes of blood-pressure-lowering drugs in treating patients with hypertension and of newer blood-pressure-lowering treatments versus untreated or less treated control conditions for a variety of other groups of patients with a high risk of cardiovascular events. Separate analyses will be conducted for the main drug classes and for major subgroups of patients defined by characteristics such as age, gender, blood pressure, diabetes, and history of renal disease, coronary heart disease or cerebrovascular disease. The principal study outcomes are stroke, major coronary heart disease events, heart failure, total cardiovascular deaths, total cardiovascular events and total mortality.

RESULTS

In total 36 trials of blood-pressure-lowering treatments potentially eligible for inclusion in this project have been identified and agreement to collaborate has been confirmed by the investigators in 30 trials, with collaboration pending for six recently identified studies. The first round of analyses will be conducted in 1999 and will be based on total cardiovascular events observed among a total of about 64,000 patients, involving about 240,000 patient-years of follow-up. The second round of analyses will be conducted in 2003 on data from at least 195,000 patients and 899,000 patient-years of follow-up. By that time it is estimated that a total of about 8000 strokes, 12,000 coronary heart disease events and 23,000 cardiovascular events in total will have occurred. This should provide good statistical power to detect even modest cause-specific differences in the incidence of the main study outcomes.

CONCLUSIONS

The combination of trial results in prospectively planned, systematic overviews both reduces random errors and avoids biases. As a consequence, this project should provide more reliable information about the effects of newer blood-pressure-lowering drugs than would any one study alone. The use of data from individual patients in these overviews will facilitate investigation of the separate effects of various drug regimens in treating members of major patient subgroups.

[Treatment patterns of hypertension in 1996. Data from the Quebec Family Practice, University of Sherbrooke registry]

OBJECTIVE

To describe the treatment of hypertension, alone or in combination with associated conditions, by a group of general practitioners in the FAMUS network and to compare these treatment patterns to the recommendations of the Canadian Hypertension Society Consensus.

DESIGN

Descriptive study based on data collected by 233 physicians in the FAMUS provincial register on hypertensive patients treated in 1996.

PARTICIPANTS

Developed between 1992 and 1996, the register contains 52,505 patients, 9,094 of whom have high blood pressure. These patients consulted their general practitioners for a complete examination. The data concern the risk factors for cardiovascular disease and include the list of medications prescribed.

MAIN OUTCOME MEASURES

Evaluation of the proportions in which various classes of medications were prescribed, and the most common combinations in relation to the presence or absence of associated conditions.

RESULTS

Of the 4,049 hypertensive patients seen in 1996, 50.2% were treated with one medication; 32.9% were treated with more than one medication; and 16.9% received no antihypertensive medication. The most frequently prescribed medications were calcium channel blockers (26.1%), followed by diuretics (25.3%), angiotensin-converting enzyme inhibitors (24.3%), and beta-blockers (20.0%). Other agents made up the remaining 4.3% of prescriptions. The proportions were similar for patients without complications who received one medication.

CONCLUSIONS

Results of this study suggest that the new molecules are widely used and that treatment patterns differ from the recommendations of the Canadian Hypertension Society Consensus, particularly in the absence of associated conditions.

[How to choose and adequate antihypertensive drug depending on the type of the existing heart damage?]

The main goal of the treatment for hypertensive vascular disease is to reduce the morbidity and mortality that follow the disease. In the patient with heart disease, the choice of antihypertensive treatment will depend on several factors, all of which must be considered prior to it: type of cardiopathy and complications, pharmacokinetics of the drug-selected and its side effects, interactions with specific treatment for the main heart disease, positive or negative interactions with risk factors and, finally, its prognostic benefits. In the present study we briefly analyze this considerations in relation to different diseases such as ischemic heart disease, ventricular dysfunction (hypertrophy, systolic and diastolic dysfunction), heart rhythm disorders (sinus node dysfunction, supraventricular and ventricular ectopies), vascular pathology (cerebral and peripheral vasculopathy) and risk factors (diabetes, dyslipemia, obesity). Based on this considerations, several recommendations are done in order to choose the best antihypertensive drug in such cardiovascular diseases.

[The advent of a new class of antihypertensive agents: angiotensin II receptor antagonists]

The objective of this article is to give more information about the pharmacology of and recent clinical data on the angiotensin II receptors antagonists. The angiotensin II receptors antagonists, of which Losartan will be the first representative on the Belgian market, constitute a new therapeutic class in the treatment of hypertension and even heart failure. They are non peptic and orally active and their long mechanism of action allows one daily administration to improve therapeutic compliance. These agents block all known effects of the angiotensin II through binding to the AT1 receptors. Thanks to this unique mechanism of action they reduce blood pressure with a lower incidence of the adverse effects commonly associated with other antihypertensives. In controlled clinical trials, overall incidence of adverse experiences was comparable to placebo. Addition of thiazide-type diuretics provides additive efficacy.

Stepped care for hypertension: are the assumptions valid?

OBJECTIVE

To examine whether the choice of initial antihypertensive medication is associated with patient withdrawal from therapy among a large cohort of newly diagnosed hypertensive individuals receiving medical care in actual practice.

DESIGN

The records of the outpatient prescription drug plan of Saskatchewan, Canada, were searched for individuals with a diagnosis of essential hypertension who were receiving at least one antihypertensive drug between January 1989 and December 1994. Persistence was defined, and records were classified by class of initial antihypertensive agent prescribed.

SUBJECTS

In all, the records of over 79,000 individuals with a diagnosis of hypertension and an antihypertensive drug prescribed between 1990 and 1994 were evaluated. Persistence with therapy was considered in a subset of newly diagnosed patients, observed for at least 6 months, and receiving an initial prescription from one of four major categories of antihypertensive agents.

RESULTS

Among newly diagnosed patients, diuretics and angiotensin converting enzyme (ACE) inhibitors were the most common initial medication. ACE inhibitors were associated with the highest persistence rates after 1 year of follow-up (83%), followed by calcium antagonists (81%), diuretics (78%) and beta-blockers (74%) (P < 0.001). These results were unchanged in a Cox proportional hazards model which controlled for confounding by age, sex and proxy measures for prior health status.

CONCLUSIONS

A significant proportion of newly diagnosed patients withdraw from therapy within the first year, and this withdrawal seems to be related to the choice of initial antihypertensive agent. These results suggest that recommendations for using stepped care in hypertension management may not be optimal if the initial agent prescribed is associated with decreased levels of persistence with therapy.

Hypertension: the rediscovery of combination therapy

Awareness and treatment of hypertension in the United States has been improving for older patients, but hypertension continues in many cases to be poorly controlled. Three options exist if initial therapy fails to achieve target blood pressure: upward drug titration, substituting another drug, or combination drug therapy. Combination therapy is the attempt to optimize blood pressure control by using two or more agents with additive or synergistic effects. Problems with this approach include noncompliance due to complicated regimens, adverse drug reactions, and the added expense of multiple medications. However, the newer fixed-dose combination products have been shown to offer improved blood pressure control, simplification of drug regimens, decreased adverse reactions, improved compliance, and cost-effectiveness.

[Role of calcium antagonists in the treatment of arterial hypertension]

We have reviewed the cardiovascular actions of calcioantagonists. These drugs act through L and T channels, inhibiting calcium ions entry at the alpha 1 subunit. The union sites for dihydropiridines (DHPs) are surfacely located (N site) compared to those of diltiazem and verapamil (D and V sites). The administration of calcioantagonists induces peripheral vasodilation with decrease of blood pressure and peripheral resistance; they also act on myocardium inhibiting AV conduction and cardiac contractility. DHPs act more specifically on vascular smooth muscle than myocardium; however, no DHPs (diltiazem and verapamil) act more specifically on myocardium than peripheral vessels. Among drugs of first generation we can mention: nifedipine, diltiazem and verapamil. Among drugs of second generation we have: lacidipine and amlodipine with better tissue selectivity and longer biological half-lives. A recently introduced compound, mibefradil, acts selectively on T channels. The use of calcioantagonists is wide: coronary disease, hypertension, cardiac arrhythmias, ischemic cerebrovascular disease, cardiac failure, primary pulmonary hypertension. World Health Organization has recommended calcium antagonists as first line drugs in hypertension as done with other compounds: diuretics, betablockers, and converting enzyme inhibitors. Recent controversial studies on calcioantogonists should be assessed adequately in order to take a definitive decision.

Report of the Canadian Hypertension Society Consensus Conference: 3. Pharmacologic treatment of hypertensive disorders in pregnancy

OBJECTIVE

To provide Canadian physicians with evidence-based guidelines for the pharmacologic treatment of hypertensive disorders in pregnancy.

OPTIONS

No medication, or treatment with antihypertensive or anticonvulsant drugs.

OUTCOMES

Prevention of maternal complications, and prevention of perinatal complications and death.

EVIDENCE

Pertinent articles published from 1962 to September 1996 retrieved from the Pregnancy and Childbirth Module of the Cochrane Database of Systematic Reviews and from MEDLINE; additional articles retrieved through a manual search of bibliographies; and expert opinion. Recommendations were graded according to levels of evidence.

VALUES

Maternal and fetal well-being were equally valued, with the belief that treatment side effects should be minimized.

BENEFITS, HARMS AND COSTS

Reduction in the rate of adverse perinatal outcomes, including death. Potential side effects of antihypertensive drugs include placental hypoperfusion, intrauterine growth retardation and long-term effects on the infant.

RECOMMENDATIONS

A systolic blood pressure greater than 169 mm Hg or a diastolic pressure greater than 109 mm Hg in a pregnant woman should be considered an emergency and pharmacologic treatment with hydralazine, labetalol or nifedipine started. Otherwise, the thresholds at which to start antihypertensive treatment are a systolic pressure of 140 mm Hg or a diastolic pressure of 90 mm Hg in women with gestational hypertension without proteinuria or pre-existing hypertension before 28 weeks' gestation, those with gestational hypertension and proteinuria or symptoms at any time during the pregnancy, those with pre-existing hypertension and underlying conditions or target-organ damage, and those with pre-existing hypertension and superimposed gestational hypertension. The thresholds in other circumstances are a systolic pressure of 150 mm Hg or a diastolic pressure of 95 mm Hg. For nonsevere hypertension, methyldopa is the first-line drug; labetalol, pindolol, oxprenolol and nifedipine are second-line drugs. Fetal distress attributed to placental hypoperfusion is rare, and long-term effects on the infant are unknown. Magnesium sulfate is recommended for the prevention and treatment of seizures.

VALIDATION

The guidelines are more precise but compatible with those from the US and Australia.

How should we treat hypertensive women with cardiac and renal impairment?

Arterial hypertension is the most common chronic medical condition requiring office visits to physicians and is a major contributing factor to the development of myocardial infarction and stroke. Its importance as a cardiovascular risk factor is at least as significant in women as in men; however, the ever-growing literature on hypertension shows surprisingly little data concerning sex differences. Large clinical trials of antihypertensive treatment have not clearly demonstrated gender differences in blood pressure response and outcome, but the majority of patients in these trials were men. Even so, some evidence indicates that white women treated for hypertension obtain less benefit than men. The pathophysiology of hypertension in men and women is similar in many aspects, but important gender differences are now emerging. Studies designed to clarify these differences are required, as a better knowledge of the underlying mechanisms will allow for a more precise stratification of risk and a more accurate approach to both nonpharmacologic and pharmacologic treatment.

A survey of management practices for isolated systolic hypertension

OBJECTIVE

To determine the management practices of clinicians for patients with isolated systolic hypertension, with particular attention to treatment thresholds, medication choices, and target blood pressures.

DESIGN

Self-administered questionnaire.

SETTING

Edmonton, Alberta, a large Canadian city.

PARTICIPANTS

A random sample of 348 family physicians and 125 internists.

MEASUREMENTS

Demographics of the respondents, first and second choice of antihypertensives, treatment thresholds, and target blood pressures for patients with isolated systolic hypertension.

RESULTS

Excluding 54 nondeliverable questionnaires, a response rate of 67% (281 surveys) was obtained. The responding clinicians reported treatment thresholds and target blood pressures consistent with the evidence from randomized clinical trials and the recommendations of the Canadian Hypertension Society and the Fifth Report of the Joint National Committee on Detection, Evaluation, and Treatment of High Blood Pressure. Thiazide diuretics were recommended as first line therapy by 74% of internists and 58% of family physicians. Angiotensin converting enzyme inhibitors were the most frequently chosen second line drug (27% of internists and 45% of family physicians).

CONCLUSIONS

The reported management practices of this group of clinicians are consistent with the evidence from randomized clinical trials and the recommendations of national consensus guidelines.

Baseline correlates with quality of life among men and women with medication-controlled hypertension. The trial of nonpharmacologic interventions in the elderly (TONE)

OBJECTIVES

To examine Quality of Life (QOL) and its correlates among older adults with medication-controlled hypertension.

DESIGN

Baseline data from the TONE clinical trial.

MEASUREMENTS

Demographic variables (age, race, income), hypertension treatment (medication class, years treated), health status (obesity, physical symptoms), and QOL status (MOS-Short-Form 36, Jenkins Sleep Disturbance, and CES-D Depression).

PARTICIPANTS

A total of 975 men and women, aged 60 to 81 years and free of major diseases and disability, with a screening blood pressure (BP) of < or = 145/85 mm Hg, treated medically for hypertension with antihypertensive medication.

RESULTS

On average, TONE participants reported a QOL level on the SF-36 that was similar to or better than that reported by older adults in the general population. However, there was a strikingly high prevalence of physical complaints or symptoms: 90.3% of men and 93.3% of women experienced one or more physical symptoms or complaints, and nearly 50% reported that such symptoms had disrupted their daily functioning. Among variables-considered, only the physical symptoms index score, number of severe symptoms, and obesity status were correlated consistently with QOL among TONE men and women. Lower QOL scores were associated with higher symptom scores and with obesity. Neither medication class nor age were appreciably associated with QOL status.

CONCLUSIONS

Physical symptoms, rather than medication class and age, were the strongest correlates of QOL in TONE. This underscores the importance of identifying the etiology of symptoms as a means to improve the QOL of order hypertensive persons rather than substituting medication. The association of poorer physical well-being with obesity suggests that weight reduction to manage BP may also improve QOL for some individuals.

Which one of the following antihypertensive medications is the least appropriate choice for patients with diabetic nephropathy. Nifedipine (e.g., Adalat) is the least appropriate choice for patients with diabetic nephropathy

Images

New or developing antihypertensive agents

Although significant pharmacologic and nonpharmacologic advances in treating hypertension during the last decade have reduced mortality and morbidity, hypertension continues to be a major health concern worldwide. Therefore, the search continues for newer specific pharmacologic treatment of this disorder. This review focuses on pharmacologic agents or classes of agents either recently approved or under clinical development for the treatment of hypertension.

[Arterial hypertension: current large therapeutic trials]

In this review, the design and objectives of ongoing clinical trials in essential hypertension are discussed along with the main results obtained from previously published therapeutic trials. In a meta-analysis of 14 of the major primary prevention trials in hypertension, the difference in diastolic blood pressure between the intervention groups and the control groups was only 5-6 mmHg. This difference was associated with significant reductions in all stroke events (42 per cent), all coronary heart disease events (14 per cent) and in cardiovascular mortality (21 per cent). In elderly hypertensive patients, available studies have shown that antihypertensive treatment reduces the incidence of non-fatal cardiovascular events without significantly modifying cardiovascular mortality. Most of these results were obtained with beta-blockers or diuretics. Despite official recommendation as first line monotherapy, none of the three new antihypertensive classes has been shown to have beneficial effects on hard primary endpoints such as cardiovascular morbidity and mortality. Several ongoing large scale randomized controlled trials vs. beta-blockers or diuretics are addressing this important issue. Moreover, other effects of antihypertensive treatment such as the 'J-curve phenomenon', the rate of change in the carotid wall thickness or the exact beneficial effects in elderly patients are being investigated in some of these studies.

Nocturnal blood pressure in treated hypertensive African Americans Compared to treated hypertensive European Americans

Previous studies have shown that African Americans (blacks) tend to have higher nocturnal blood pressure than European Americans (whites). The study presented here was undertaken to determine whether treatment of hypertension influences nocturnal blood pressure differently in blacks than in whites. To answer this question, this study measured nocturnal blood pressure by ambulatory blood pressure monitoring (ABPM) in treated hypertensive blacks and whites whose daytime blood pressures were comparable. Inclusion criteria for this study were: diagnosis of essential hypertension, absence of renal failure, and documentation of antihypertensive therapy, diabetic status, proteinuria status, and body weight. All of the black patients in our programs who underwent ABPM and met the above criteria were included in this study. White patients were included on the basis of having the same inclusion criteria as blacks and showing, by ABPM, daytime mean arterial pressure (MAP) in the same range as that of the blacks selected for this study. The results of nocturnal blood pressure were unknown to the investigators when the patients were selected for this study. In the blacks (N = 62) and whites (N = 72) selected for study, the mean daytime (0600 to 2200 h) MAP was 107 +/- 1 SE mm Hg for both the black and white cohorts. To assess nocturnal blood pressure, the period from 0100 to 0500 h was chosen because it likely encompassed an interval of sleep, which is associated with the nadir of nocturnal blood pressure. This interval was termed 0100 to 0500 h, "middle night." Mean middle night MAP was 97 +/- 12 mm Hg in blacks versus 90 +/- 14 mm Hg in whites (P < 0.006, unpaired t test). The greater middle night MAP in blacks compared with whites was a result of the higher diastolic pressure in blacks (80 +/- 11 mm Hg) versus whites (75 +/- 11 mm Hg) (P = 0.003). Mean middle night systolic blood pressure was numerically higher in blacks than whites (131 +/- 18 mm Hg versus 128 +/- 17 mm Hg), but this difference did not achieve statistical significance. The higher middle night blood pressure in blacks versus whites could not be explained by differences between the groups in daytime MAP, age, gender, body weight, serum creatinine level, proteinuria, diabetic status, or greater use of short-acting antihypertensive agents in blacks versus whites. It was concluded that when treated hypertensive blacks and whites are matched for the same daytime blood pressure, blacks tend to have significantly higher nocturnal blood pressure than whites. The magnitude of this difference suggests that it could contribute importantly to the greater target-organ damage that is seen in hypertensive blacks compared with hypertensive whites.

Antihypertensive medication use among recruits for the Trial of Nonpharmacologic Interventions in the Elderly (TONE)

OBJECTIVES

To examine the distribution and correlates of the classes of antihypertensive medications taken by persons aged 60 to 80.

DESIGN

Cross-sectional screening.

SETTING

Four academic medical centers in the southern and eastern United States.

PARTICIPANTS

Volunteers (N = 2601) entering a clinical trial testing the value of nonpharmacologic approaches to control blood pressure who were either taking one or two (single or combined) medications for the treatment of hypertension and expressed willingness to be withdrawn from these medications according to a standardized protocol.

MEASUREMENTS

Medication use, blood pressure, and data from self-administered questionnaires collected during standardized clinic visits.

RESULTS

Calcium channel blockers (23.9%) were the most frequent single agent antihypertensive medications used by cohort members, followed by diuretics (17.9%) and angiotension-converting enzyme (ACE) inhibitors (17.5%). The most common combination agents were composed of diuretics with either calcium channel blockers (5.4%), ACE inhibitors (4.0%), or beta-blockers (3.7%). Women were twice as likely to be taking diuretics, and less likely to be taking ACE inhibitors and beta-blockers, than men. Blacks were more likely to be taking diuretics and calcium channel blockers, and less likely to be taking beta-blockers and ACE inhibitors, than others. These relationships could not be attributed to differences in geographical area, other demographic factors, age, or medical history.

CONCLUSIONS

These usage patterns appear to mirror those in the population of the United States as a whole, which has trended toward greater usage of calcium channel blockers and ACE inhibitors with declining use of diuretics. The distribution of antihypertensive medications among older hypertensives is markedly different between women and men and between black Americans and others.

Dynamic competition as an exploratory model of healthcare policy for the antihypertensive market

Dynamic competition based on innovation, rather than classical competition based on price, may better explain the research-intensive pharmaceutical market. In an exploratory comparison of these models, economic indicators of annual change in price and price elasticity of demand were tested in a repeated-measures design by analysis of variance. Between 1990 and 1992, updated US prescribing guidelines for hypertension provided a framework in which the contrast between 2 newer classes and 2 older classes of first-line therapies served as a marker for innovation. The principal hypothesis was that newer classes would be less elastic than older classes, but with such innovation-based differences eroding over time. Although temporarily greater inelasticities for newer classes supported dynamic competition, initially extreme inelasticities for newer classes indicated a market distortion or a shifting demand curve. These exploratory results, although requiring substantiation, point toward using dynamic competition in crafting healthcare policy for the pharmaceutical market.

Review: the effects of antihypertensive agents on serum lipids

Because various antihypertensive drugs adversely affect lipid metabolism, these drugs may increase associated risks for coronary artery disease and thus offset some of the beneficial effects of blood pressure reduction. In this paper the current literature regarding the effects of antihypertensive agents on serum lipids is reviewed. Differing effects of various classes of antihypertensives are assessed to further our understanding of this very important subject.