Hypertension in blacks

The major differences that have been recognized between black and white hypertensives are primarily epidemiologic, with hypertension being more prevalent, having an earlier onset, and having more severe sequelae in the black population. The cause of the problem in both black and white people remains obscure, but it appears that a difference in sodium handling may contribute to the particular hemodynamic and hormonal profile of black hypertensives. Salt sensitivity, expanded plasma volume and low renin levels have been the hallmark of the black hypertensive. Complications such as stroke and left ventricular hypertrophy remain the major sequelae of this disease in blacks. Finally, a current study confirmed the improved efficacy of antihypertensive therapy in blacks to diuretics and calcium channel blockers and a somewhat lower efficacy profile to angiotensin converting enzyme inhibitors and beta blockers, although the latter classes of agents have shown better response in blacks than previously thought.

[Development of antihypertensive drug consumption in the Toulouse University Regional Hospital Center from 1981 to 1989]

Eighties were characterized by the introduction of two new pharmacological class of antihypertensive drugs [converting enzyme inhibitors (CEI) and calcium channel blockers] and the publication of several large scale antihypertensive trials. The consumption of antihypertensive drugs at the Toulouse Universitary Hospital was evaluated during the ten last years. Total consumption remained stable until 1985 (560,000 pinch units) and raised to 650,000 in 1988. This number decreased to 580,000 in 1989. Consumption of diuretics remained stable during these years whereas beta-blocking agents slightly decreased. The global increase of prescription was explained by the introduction of CEI and a marked rise in calcium channel blockers from 1986. In contrast, consumption of central antihypertensive drugs crushed from 1982 to equal vasodilators (direct + alpha-blocking agents) in 1989.

Randomized trials in the study of antihypertensive drugs

Heterogeneity in response to antihypertensive drugs can be addressed by randomized trials in individual subjects. In such a trial a patient receives pairs of treatment periods (one period of each pair active drug, one matched placebo, in random order); patient and clinician are blinded to allocation, and treatment targets are monitored. These trials can optimize antihypertensive therapy in clinical practice and facilitate the investigation of new drugs and the study of pathophysiology. Such trials also have potential in helping decide whether common, nonspecific symptoms reported by patients are really drug related.

Characteristics of participants at baseline in the Treatment of Mild Hypertension Study (TOMHS)

The Treatment of Mild Hypertension Study (TOMHS) is a randomized, double-blind clinical trial currently being conducted to compare the effects of nonpharmacologic therapy alone with those of 1 of 5 active drug regimens combined with nonpharmacologic therapy, for long-term management of patients with mild hypertension. Six classes of drugs were studied: (1) acebutolol (beta blocker), (2) amlodipine (calcium antagonist), (3) chlorthalidone (diuretic), (4) doxazosin (alpha 1 antagonist), (5) enalapril (angiotensin-converting enzyme inhibitor) and (6) placebo. All participants received nutritional-hygienic advice to reduce weight and sodium and alcohol intakes and to increase physical activity. End points include blood pressure change, side effects and quality-of-life indices; incidence of electrocardiographic and echocardiographic abnormalities; and incidence of cardiovascular clinical events, including death, among participants receiving drugs as first-step treatment as well as nonpharmacologic treatment compared with incidence among those participants randomized to nonpharmacologic treatment only as the initial step.

Treatment of high blood pressure--the effect on coronary morbidity and mortality

Established drugs used in the treatment of hypertension have reduced stroke but have had disappointingly little impact on coronary artery disease and its complications. This could be due to inadequate falls in blood pressure (or excessive falls). It is possible that the role of blood pressure in ischaemic heart disease has been over-estimated compared to other risk factors. Alternatively, the drugs used previously may have adversely affected other factors. Mortality in treated hypertensives remains higher than normotensives but so does their blood pressure. The blood pressure on treatment is a much better predictor of outcome than initial blood pressure. This suggests that improved blood pressure control may be desirable. In our hospital-based hypertension clinic many patients have more than one risk factor. In spite of intensive efforts between 1980 and 1988, smoking habits changed little and serum cholesterol and random blood glucose actually rose. Cholesterol is high in our population of hypertensive patients and the mean (+/- SD) rose from 6.4 +/- 1.3 to 6.6 +/- 1.3 (n = 127; P less than 0.01). These observations highlight the importance of a multiple risk factor approach. The benefits of alternative drugs which can lower total cholesterol and/or low-density lipoprotein (LDL) and/or raise high-density lipoprotein (HDL) deserve study in this population. A final possibility is that the widely observed association between hypertension and ischaemic heart disease is not causal (or is weak compared to other risk factors). If a common underlying mechanism caused both atheroma and hypertension then reduction of blood pressure would not be expected to reverse atheroma and its complications. At present this possibility cannot be excluded.

Establishing the effect of antihypertensive treatment on coronary morbidity and mortality

The results of the major antihypertensive trials are reviewed. Most of them were too small to detect significant differences on coronary heart disease (CHD) incidence. The pooled result was not significant for the effect on CHD; for stroke it was significant in some of the individual trials and significant when the data were pooled. The results of treatment in a general population sample and the 'J'-shaped curve relation between achieved blood pressure and CHD incidence are discussed. Reasons for the stronger effect on stroke compared with CHD, may be: A longer treatment period needed to affect CHD. --Effects on other risk factors such as lipid levels and smoking are needed to influence CHD incidence. Negative metabolic effects from treatment may be counteractive. More basic mechanisms in the process leading to hypertension and CHD may have to be affected.

Behavioural consequences of hypertension: effects of age and type of antihypertensive agent

In order to investigate the effects on behaviour of hypertension, age, and the types of antihypertensive agents, we have conducted a retrospective analysis in 100 hypertensive patients receiving chronic treatment in our Hypertension Clinic. A group of 80 normotensive subjects, matched for age, were included in the study. Half of the hypertensive patients were under the age of 50 (young group) and half were over the age of 50 yrs (old group). The antihypertensive agents had not been administered according to any specific protocol, but represented the choice of the individual clinicians treating the patients in the clinic. All patients had received treatment for at least one year, and usually for two years. The behavioural tests performed were designed to measure sensory-perceptive ability, cognitive ability and psychomotor function and were those employed and described in our previous studies. The results achieved were varied, but indicated that older age was associated with an impairment in performance as was blood pressure. Test performances in the young hypertensives were similar to those achieved by older normotensives. These results were more prominent in cognitive and psychomotor functions than in the sensory-perceptive tests. The antihypertensive drugs used also affected these results; the worst behavioural performances tended to be in patients receiving the central nervous system agonists (methyl-dopa and clonidine) and better performances in patients receiving beta-blockers alone when compared with the other groups. Surprisingly, patients receiving diuretics showed poorer performance levels, but these were better in patients who received a beta-blocker in combination with their diuretic.(ABSTRACT TRUNCATED AT 250 WORDS)

Patterns in the drug treatment of hypertension in Auckland, 1982-7

This paper examines the pattern of drug treatment of hypertension in Auckland in the period 1982 to 1987 using data from a representative sample of the adult population interviewed in 1982 and followed up in 1987. In 1982 the age standardised prevalence of antihypertensive treatment for people aged 40-64 years was 12.2% (95%Cl 10.4, 14.0) and in 1987 it was 10.2% (95%Cl 8.5, 11.8). Over the five year period of this study, 6% of the sample untreated in 1982 began treatment with antihypertensive medication, while 24% of those on drugs in 1982 had stopped treatment by 1987. The most common medications used in both 1982 and 1987 for hypertension were diuretics and beta blockers. Over the five year period diuretic use fell and beta blocker use remained constant. In 1982 3% of hypertensives were taking a calcium antagonist but in 1987 13% were on these drugs and a further 13% were using ACE inhibitors. This study suggests that the prevalence of drug treatment for hypertension has plateaued in New Zealand; coincidentally there is a trend towards use of more expensive drugs.

Variability in antihypertensive drug therapy in general practice: results from a random national survey

A random national survey of 50 general practitioners was undertaken to ascertain current trends in the pharmacological management of hypertension. Forty general practitioners entered the study, and scripts written by them over a two month period in 1988 were collected and recorded by the pharmaceutical pricing offices of the health department. The general practitioners provided details on whether the script had been written for hypertension, as well as the age and sex of the patients. Information from 37 general practitioners was available for study, involving 2675 scripts written for hypertension for 1858 patients. Sixty point two percent of the treated hypertensives were female, and 58.9% were aged over 60 years. The most commonly prescribed antihypertensives were the diuretics (47.1% of patients) and beta blockers (47.9%). They were followed by angiotensin converting enzyme inhibitors (18.2%) and calcium antagonists (9.7%). There was substantial variability in the prescription of antihypertensives with respect to the age and sex of the patients treated; the mean costs and duration of supply of different generic drug types; and the prescribing habits of general practitioners. By generic type, the mean monthly costs of therapy ranged from $3.77 (diuretics) to $48.19 (calcium antagonists). The age and sex adjusted geometric mean script costs ranged from $17.78 to $49.11 per month (median: $29.30). It seems unlikely that the observed degree of variability is explained by differences in the severity of hypertension between general practice populations.

Hypertension in elderly patients

PURPOSE

To synthesize and analyze new information on the epidemiology, pathophysiology, and management of hypertension in the elderly to guide physicians making treatment decisions.

DATA IDENTIFICATION

An English-language literature search using MEDLINE (1972-1988) and bibliographic reviews of textbooks and review articles.

STUDY SELECTION

Primary research articles on the epidemiology, pathophysiology, and management of hypertension in the elderly were reviewed. Particular emphasis was placed on large randomized clinical trials.

DATA EXTRACTION

Study design and quality were assessed, with particular attention to subject selection, sample size, definition of outcome variables, and applicability of the results to management of the elderly hypertensive patient.

RESULTS OF DATA SYNTHESIS

Epidemiologic studies confirm that elevated systolic blood pressure in the elderly is more highly correlated with subsequent cardiovascular morbidity and mortality than is elevation of diastolic blood pressure. Results of several large randomized trials of the treatment of diastolic hypertension in elderly patients indicate that treatment is beneficial, at least up to age 80. For instance, the European Working Party on Hypertension in the Elderly reported that drug treatment resulted in a significant relative reduction (27%) in overall cardiovascular mortality, or an absolute reduction of 29 fewer cardiovascular events per 1000 person-years of treatment. Data from well-designed studies are not available to make a definitive statement about the treatment of isolated systolic hypertension.

CONCLUSION

The cardiovascular risk reduction from treating mild to moderate diastolic hypertension in the elderly is significant, but the magnitude of absolute risk reduction is not so great that treatment should invariably be pursued if serious side effects cannot be avoided.

Cerebral blood flow and its pathophysiology in hypertension

In chronic hypertension, the lower limit of autoregulation of cerebral blood flow (CBF) is shifted towards high blood pressure with a consequent impairment of the tolerance to acute hypotension. Despite this, antihypertensive treatment in the great majority of patients prevents stroke and the risk for treatment-induced cerebral ischemia is only real in a limited number of clinical settings such as malignant hypertension, hypertension in the elderly, and hypertension associated with acute stroke. During long-term treatment adaptive hypertensive changes in CBF autoregulation may be reversible, especially in young patients. Drugs used for emergency lowering of blood pressure may be classified into four groups according to their effect on CBF and intracranial pressure: (1) drugs with no pharmacological action in the cerebral circulation; (2) cerebral vasodilators; (3) alpha-adrenergic and ganglionic blockers; and (4) angiotensin-converting enzyme (ACE) inhibitors. Oxygen saturation in the jugular venous blood is of the order of 60% to 70% and is considerably higher than in the coronary sinus. It is hypothesized that this oxygen reserve enables the brain better than the heart to take hemodynamic advantage of pressure lowering without risking tissue ischemia. This may explain why antihypertensive treatment prevents stroke but not myocardial infarction. Acute hypertensive encephalopathy is probably caused by failure of autoregulatory vasoconstriction with focal or generalized dilatation of small arteries and arterioles. This is associated with a high CBF, dysfunction of the blood-brain barrier, and the formation of brain edema that is thought to cause the clinical symptoms.

Angiotensin-converting enzyme inhibitors. Emerging differences and new compounds

Angiotensin-converting enzyme inhibitors (ACEIs), introduced in clinical practice in 1980, are a relatively new class of drugs. They have been useful in the treatment of hypertension, where they are effective monotherapy in 40% to 50% of the patients and in combination therapy in up to 90%. They are also useful in the symptomatic and hemodynamic improvement and in decreasing mortality of patients with congestive heart failure. In this respect, they appear to be superior to other vasodilators. The clinical success of the marketed compounds and the expected increase in market share of these drugs, estimated to approach one billion dollars in the next few years, has created great interest among clinicians and within the drug industry. The emerging differences among the three marketed ACEIs and promising new agents that are expected to be marketed in the next few years are the subject of this review.

Effects of antihypertensive agents on circadian blood pressure and heart rate patterns. Review

Blood pressure and heart rate exhibit a circadian rhythm, with both rising rapidly during the morning hours and then decreasing throughout the day to a nadir around 3 AM. Current evidence suggests a possible link between cardiovascular events, such as myocardial infarction and sudden cardiac death, which have been shown to occur most frequently during the morning hours, and the rapid rise in blood pressure and heart rate during this same time period. We review data from ambulatory blood pressure studies to ascertain which antihypertensive agents provide the most satisfactory control of blood pressure and heart rate during the hours of 6 AM to 12 noon. Of the forms of drug therapy studied, labetalol, a combined alpha- and beta-blocker, and two calcium channel blockers, nifedipine and verapamil, appear to be the most effective in blunting the rise in arterial blood pressure during these critical morning hours.

The evolution of current hypertension therapy

There has been a continuous evolution in hypertensive therapy during the last 30 years. Now, physicians have access to more than 40 agents for treating this widespread condition. Large-scale clinical trials have established that lowering blood pressure in patients with mild to moderate diastolic hypertension results in a decreased incidence of stroke and, to a lesser extent, a reduction in incidence of coronary heart disease [MacMahon SW, Cutler JA, Furberg CD, et al: Prog Cardiovasc Dis 1986; 29 (suppl 1): 99-118]. Even so, the decrease in overall mortality rate is not consistent. Although hypertension occurs with increasing frequency in those over 60 years of age, patients in this age group represent less than 12 percent of the subjects in large trials. Currently, stepped-care is the recommended approach for managing hypertension in patients of all ages. However, the availability of a variety of agents for initial therapy, all with approximately equal efficacy but differing side-effect profiles, calls such an approach into question.

Diagnosis ex juvantibus. Individual response patterns to drugs reveal hypertension mechanisms and simplify treatment

Heterogeneity of response to antihypertensive therapy is a well-recognized clinical phenomenon. An agent that is antihypertensive in one patient may increase blood pressure in another or have no effect in a third. We believe that this variety of individual response to drug treatment can provide a new framework for the study of hypertensive subjects. Different patterns of response elicited by sequential trials of individual drugs with different mechanisms of action (diuretics, calcium channel blockers, alpha-blockers, beta-blockers, and converting enzyme inhibitors) should provide another means to classify hypertensive patients into biologically relevant groups. The documentation and analysis of this therapeutic heterogeneity in relation to renin profiling and to other physiological and demographic parameters may add a new dimension to the investigation of the pathophysiology of hypertension; it may serve as a basis for more appropriate stratification of participants in clinical trials and may ultimately contribute to a more rational approach to patient management.

Recent issues in antihypertensive drug therapy

Results of recent large scale treatment trials have demonstrated that aggressive management of high blood pressure prevents progression of mild hypertension to the accelerated or malignant phase and reduces incidence of stroke, congestive heart failure, and left ventricular hypertrophy. These trials mostly have utilized a diuretic-based, stepped-care approach to drug therapy, however, and have not shown a consistent beneficial effect of treatment on coronary heart mortality. In addition, the results of studies such as MRFIT have raised questions about serious risks of diuretic treatment in selected patients. These concerns have led to increased use of nonpharmacologic approaches to lowering blood pressure in patients with mild hypertension, but most patients ultimately require drug therapy. Alternative agents to diuretics now being employed as monotherapy in mild hypertension include beta-blockers, calcium channel blockers, ACE inhibitors, alpha-blockers, alpha- and beta-blockers, and, to a lesser extent, centrally-acting sympatholytics and peripheral adrenergic antagonists. Rational use of these agents primarily is based on a careful evaluation of concomitant medical conditions (see Table 3), as well as their mode of action, relative side effects, ease of administration, and cost. Age and race recently have been found to be important determinants of antihypertensive response to agents such as diuretics, beta-blockers, calcium channel blockers, and ACE inhibitors (see Table 3) and appreciation of these relative differences may affect drug selection. When these factors are taken into account, an effective and well tolerated regimen can be tailored to the individual patient. It is hoped that aggressive treatment of hypertension in the future will cause a further decline in cardiovascular mortality in the United States.

Antihypertensive drugs in pregnancy

This article considers the pathophysiology, diagnosis, and etiologies of hypertensive conditions, and considers specific agents for treating this condition. It also reviews the side effects of these agents and their efficacy, and details their use in the hypertensive pregnant patient.

The antihypertensive agents: clinical pharmacology and therapeutic monitoring

There are currently six major classes of antihypertensive drugs. This article focuses on those agents developed and marketed since 1980, paying particular attention to the pharmacokinetics and pharmacodynamics of the various compounds.

Antihypertensive drugs: how different classes can impact patients' coronary heart disease risk profile and quality of life

Diuretics, adrenergic inhibitors, and vasodilators--the three major classes of drugs used in the treatment of hypertension--have an impact on coronary heart disease. All three types of treatment reduce blood pressure to about the same degree, but with considerable individual variability with respect to their impact (positive or negative) on coronary heart disease risk. Hypokalemia, increased cholesterol levels, and hyperglycemia are common side effects of diuretic therapy that may exert a negative impact on coronary heart disease risk. Of the adrenergic inhibitors, the central agonists reverse left ventricular hypertrophy, whereas the alpha blockers generally have no adverse effect on cholesterol levels and may block coronary alpha receptors, both of which would have a positive impact on coronary risk. Beta blockers, the other class of adrenergic inhibitors, produce effects that can both negatively impact (lower high-density lipoprotein cholesterol levels and increase triglyceride levels) and positively impact (prevent arrhythmias and reverse left ventricular hypertrophy) coronary heart disease risk. The various types of vasodilators affect coronary risk differently: direct vasodilators stimulate sympathetics (negative impact), and converting enzyme inhibitors reverse left ventricular hypertrophy (positive impact). The effects of diuretics, adrenergic inhibitors, and vasodilators on all of these parameters need to be considered in the choice of therapy, particularly for the majority of asymptomatic patients with mild hypertension who are at relatively low risk for coronary heart disease.

Treatment of hypertension in the 1990s. Optimizing the benefit of blood pressure reduction by minimizing risk factors for cardiovascular disease

Due to the potency and multiple actions of available agents, current antihypertensive therapy can control blood pressure in virtually every patient with hypertension. In the past, physicians were primarily concerned with blood pressure reduction; the side effects of antihypertensive agents were a matter of lesser concern. Today, however, drugs can be selected for therapy on the basis of providing optimal antihypertensive efficacy and minimal harmful side effects. Furthermore, now that blood pressure can be effectively managed and the overall incidence of stroke has been reduced, perhaps the aim of therapy in patients with hypertension should include the reduction of coronary heart disease incidence. Three broad categories of antihypertensive agents are available: diuretics, antisympathetic agents, and vasodilators. Each class of drugs has its own pattern of action and produces optimal efficacy in identifiable patient populations, and each has a distinct side-effect profile. Knowledge of these variables and a scheme that can identify patients likely to benefit from a specific agent are paramount considerations in the treatment of hypertension.

Current therapeutic concepts in diabetic hypertension

Diabetes mellitus and hypertension are both prevalent in the adult population. The development of hypertension in the diabetic patient is likely to increase the morbidity and mortality in a subgroup already at high risk for atherosclerosis and deserves special consideration. Several studies have confirmed the beneficial effects of antihypertensive therapy on complications such as diabetic nephropathy. This emphasizes the importance of normalizing blood pressure in the diabetic population. It has been suggested that the threshold for initiating antihypertensive therapy should be lower in diabetic patients. All antihypertensive agents have potential disadvantages in patients with diabetes. The commonly encountered effects include deterioration of diabetic control, sexual dysfunction, electrolyte imbalance, and lipid disorders. The adverse effects of these agents on serum lipids have been implicated in the less-than-expected reduction in coronary heart disease noted in some studies. The recent Lipid Research Council study has emphasized the importance of elevated lipid levels and increased cardiovascular mortality. Antihypertensive therapy has advanced rapidly in the last 5 yr. The special problems in the treatment of hypertension within the diabetic population are now receiving greater attention. Undesirable biochemical side effects of drugs used to treat hypertension have become publicized, and the long-term consequences of these abnormalities are under critical scrutiny. The new antihypertensive medications offer exciting alternative approaches to the more traditional agents with less chance of significant metabolic side effects.

Survey of new antihypertensive drugs: 1982

Over 500 compounds reported to have antihypertensive activity have been cataloged from the world literature (1979-1982). The agents were classified according to mechanism: 1) drugs interacting at alpha-adrenoceptor sites; 2) beta-adrenoceptor antagonists; 3) drugs interacting with the autonomic nervous system by mechanisms other than 1 and 2; 4) inhibitors of the renin-angiotensin system; 5) diuretics; 6) vasodilator antihypertensives; and 7) drugs with miscellaneous mechanisms and/or sites of action. Within each class the drugs were subclassified and compounds that best fit the prototypes identified. The scheme is subjective, largely because of conflicting information cited in the literature. It is clear that many new drugs are at various stages of development. Whether or not these drugs will survive the scrutiny of rigorous and lengthy preclinical and clinical development, and in fact prove to be better antihypertensive agents than the currently marketed agents, remains to be established.

Adverse effects of antihypertensive drugs

Early essential hypertension is asymptomatic and should remain so throughout treatment. In view of the increasing number of available antihypertensive agents, clinicians need to become familiar with the potential side effects of these drugs. By placing more emphasis on non-pharmacological treatment (sodium restriction, weight loss, exercise) and thoroughly evaluating each case in particular, the pharmacological regimen can be optimally tailored to the patient's needs. Potential side effects should be predicted and can often be avoided; if they become clinically significant they should be rapidly recognised and corrected. These side effects can be easily remembered in most instances, as they fall into 3 broad categories: (a) those caused by an exaggerated therapeutic effect; (b) those due to a non-therapeutic pharmacological effect; and (c) those caused by a non-therapeutic, non-pharmacological effect probably representing idiosyncratic reactions. This review focuses mainly on adverse effects of the second and third kind. Each group of drugs in general shares the common side effects of the first two categories, while each individual drug has its own idiosyncratic side effects.

[Hemodynamic effects of antihypertensive drugs]

The physiopathology of hypertension is not fully understood, though the haemodynamic pictures accompanying the various arterial forms have been established. Clinical employment of antihypertensive drugs should tend to correct these pictures and the extent to which this is true is examined in the light of the latest evidence with respect to the drugs most commonly used.

Adverse drug reactions during treatment of hypertension

Adverse drug reactions (ADRs) can be broadly classified as either "a nuisance" or "life-threatening". Voluntary reporting systems gradually accumulate a quite impressive list of suspected ADRs with antihypertensive drugs as their use becomes widespread. Such data gives no clue to true or relative incidence. The absolute and comparative incidence of ADRs can only be determined fairly by a system of unbiased general data collection of ADRs from which the data for antihypertensive drugs is then selected. The Boston Collaborative Drug Surveillance Program provides such a source of information. Data from the Boston Program reveals that most of the listed ADRs with antihypertensive drugs occur very infrequently, that "nuisance" ADRs occur in 10 to 29% of patients in whom they are used, and that "life-threatening" ADRs occur in less than 1%. ADRs tend to discourage patient compliance with medication aims. In selecting specific antihypertensive therapy the clinician should be mindful not only of the severity of the hypertension to be treated, but also of the nature, type, and severity of potential ADRs, the personality and likely complicance of the patient, and the need for patient education regarding drug effects, possible unwanted effects, and what measures should be taken when ADRs occur.

Current therapy of hypertension. A pharmacologic approach

Adequate treatment of hypertension requires that the physician understand the pharmacologic actions of antihypertensive agents. Although no drug is without adverse reactions, it should be possible to choose an agent or combination of agents which can effectively lower blood pressure and be tolerated by the patient. The indications, proposed mechanisms of actions and adverse effects of the following antihypertensive drugs are discussed: thiazide diuretics, spironolactone, triamterene, trimethaphan, Rauwolfia alkaloids. guanethidine, bethanidine, methyldopa, clonidine, pargyline, propranolol, hydrazaline, minoxidil, guancydine, diazoxide and sodium nitroprusside.