Trends in the use of blood pressure lowering medications in Auckland, and associated costs, 1982-94

AIM

To describe the trends to the use of blood pressure lowering medication and associated costs in Auckland, New Zealand between 1982 and 1994.

METHODS

Three cross sectional surveys of cardiovascular risk factors in people aged 35-64 years have been conducted in the Auckland region in 1982, 1986-8 and 1993-4, with random selection of 3804 European men and women from Auckland electoral rolls.

RESULTS

Mean systolic and diastolic blood pressure fell significantly in both sexes between 1982 and 1993-4. There was a possible trend towards a decrease in the proportion of the survey population taking blood pressure lowering drugs with 9.3% on medication in 1982 and 8.0% in 1993-4, while the number of drugs prescribed per person for blood pressure control declined from 1.41 to 1.15. As a percentage of the total antihypertensive drug use in the population, diuretic use dropped from 40.3% to 11.7%, and beta blockers decreased from 36% to 27%. Angiotensin converting enzyme (ACE) inhibitors that were unavailable in 1982, were the most commonly prescribed antihypertensive at 35.8% in 1993-4 and calcium antagonists increased from 2% in 1982 to 22.1% in 1993-4. In 1995 dollars the average daily cost of blood pressure lowering medication per person has increased from 35 cents in 1982 to 76 cents in 1994.

CONCLUSION

Over the 12 year survey period ACE inhibitors, beta blockers and calcium antagonists have replaced diuretics as the major antihypertensive drugs used in the Auckland population. This has resulted in an increase in the average daily cost of antihypertensive drug therapy per person of approximately 100% in the period 1982-94.

Long-term effects on plasma lipids of diet and drugs to treat hypertension. Treatment of Mild Hypertension Study (TOMHS) Research Group

OBJECTIVE

- To compare long-term plasma lipid changes among 6 antihypertensive treatment interventions for stage I (mild) hypertension.

DESIGN

- Multicenter, randomized, double-blind, parallel-group clinical trial.

SETTING

- Four academic clinical research units in the United States.

PARTICIPANTS

- A total of 902 men and women, aged 45 to 69 years, with stage I diastolic hypertension (diastolic blood pressure <100 mm Hg), recruited from 11914 persons screened in their communities.

INTERVENTIONS

- Participants were randomized to 1 of 6 treatment groups: (1) placebo, (2) beta-blocker (acebutolol), (3) calcium antagonist (amlodipine), (4) diuretic (chlorthalidone), (5) alpha1-antagonist (doxazosin), and (6) angiotensin-converting enzyme inhibitor (enalapril). All groups received intensive lifestyle counseling to achieve weight loss, dietary sodium and alcohol reduction, and increased physical activity.

MAIN OUTCOME MEASURES

- Changes in plasma total cholesterol, high-density lipoprotein (HDL) cholesterol, low-density lipoprotein (LDL) cholesterol, and triglycerides from baseline to annual visits through 4 years.

RESULTS

- Mean changes in all plasma lipids were favorable in all groups. The degree of weight loss with fat-modified diet and exercise was significantly related to favorable lipid changes. Significant differences (P<.01) among groups for average changes during follow-up in each lipid were observed. Decreases in plasma total cholesterol and LDL cholesterol were greater with doxazosin and acebutolol (for plasma total cholesterol, 0.36 and 0.30 mmol/L [13.8 and 11.7 mg/dL], respectively), less with chlorthalidone and placebo (0.12 and 0.13 mmol/L [4.5 and 5.1 mg/dL], respectively). Decreases in triglycerides were greater with doxazosin and enalapril, least with acebutolol. Increases in HDL cholesterol were greater with enalapril and doxazosin, least with acebutolol. Significant relative increases in plasma total cholesterol with chlorthalidone compared with placebo at 12 months were no longer present at 24 months and beyond, when mean plasma total cholesterol for the chlorthalidone group fell below baseline. Analyses of participants continuing to receive chlorthalidone throughout the 4 years of follow-up indicated this was not due solely to an increasing percentage of participants changing or discontinuing use of medication during follow-up.

CONCLUSIONS

- Weight loss with a fat-modified diet plus increased exercise produces favorable long-term effects on blood pressure and all plasma lipid fractions of adults with stage I hypertension; blood pressure reduction is enhanced to a similar degree by addition of a drug from any one of 5 classes of antihypertensive medication. These drugs differ quantitatively in influencing the degree of long-term favorable effects on blood lipids obtained with nutritional-hygienic treatment.

Choice of initial therapy for hypertension

Hypertension is one of the most common conditions treated by the clinician, yet accurate diagnosis and selection of the appropriate treatment can be challenging and recommendations regarding antihypertensive medications continue to evolve. The fifth report of the Joint National Committee on Detection, Evaluation, and Treatment of High Blood Pressure recommends diet and exercise for the initial treatment of mild hypertension, followed by a diuretic or beta-blocker if necessary, unless contraindicated. This recommendation is based on outcome studies using these drugs that demonstrate reductions in major diseases that treatment of hypertension is intended to prevent: stroke and cardiovascular morbidity and mortality. Other antihypertensive drugs, while not tested in large trials evaluating outcomes, have unique advantages for certain patients. Consideration of the patient's medical conditions and needs, including the cost of medication, is essential to ensuring optimal treatment of hypertension.

Managing the diabetic hypertensive patient

Table 1 shows how the five major drug groups interact with those variables which should be especially considered when treating the hypertensive diabetic. While diuretics are sometimes required in severely hypertensive cases-particularly when fluid retention is part of the clinical picture, and beta blockers are the outstanding choice for those with active CHD- the newer agents, particularly ACE inhibitors and alpha blockers, appear, in theory, to be better agents in terms of preventing the major adverse cardiovascular events to which diabetics are so prone. These two types of agents are very effective together and the addition of a calcium antagonist is likely to control the blood pressures of the vast majority of patients. However, one or more randomized controlled trials to evaluate whether recommendations such as these are valid is desperately needed. Meanwhile, each physician is left to make his or her own best estimate as to which drug to use and at what threshold.

[Hypertension. A new way to approach an old problem]

High blood pressure is frequently seen in family practice. In response to recent surveys and clinical trials, the Canadian Hypertension Society has changed its recommendations on the management of HBP. This article reviews family physicians' approach to HBP according to the recent report of the Canadian Hypertension Society Consensus Conference.

Current considerations in patients with coexistent diabetes and hypertension

Primary health care providers frequently manage patients with diabetes and hypertension as co-morbid conditions. Because of the increased complexity and morbidity that occur when these conditions coexist, it is essential that practitioners remain aware of current treatment considerations and options, which are essential in helping patients manage this condition. This article reviews current considerations in the management and care of hypertension in diabetic patients. Possible differential diagnoses are considered, and current recommendations for essential nonpharmacological treatment approaches are reviewed. Particular emphasis is placed on the choice and initiation of pharmacological therapy for hypertension in the diabetic and the unique considerations necessary in this patient population. Standards of care for diabetic patients with the complication of hypertension are reviewed.

Who is using antihypertensive drugs? A prescription analysis from Finland

OBJECTIVE

To analyse the prescribing of antihypertensives in Finland in 1993.

DESIGN

A descriptive three-month follow-up study of reimbursed prescriptions for chronic hypertension dispensed in Finnish pharmacies.

SETTING

The nationwide prescription data base of the Social Insurance Institution covering 80% of Finnish pharmacies. Material--The study material consisted of 479 744 antihypertensive prescriptions from ATC-groups hypotensives (C02), diuretics (C03), beta blocking agents (C07), and potassium (A12B) for 279 435 hypertensive patients.

RESULTS

Of all the prescriptions (excluding potassium supplements), 30% were for beta blocking agents, 24% for diuretics, 22% for calcium channel blocking agents, 20% for ACE inhibitors or ACE inhibitor + diuretic combinations, and 4% for other hypotensives. Two thirds of the men received a drug from a hypotensive group, nearly half were prescribed a beta blocking agent, and 27% a diuretic. Among women the distribution of the different drug groups was more even: more than half the women (55%) were prescribed hypotensives while beta blocking agents and diuretics were prescribed for 43% and 44%, respectively. Due to the different treatment profile between men and women the expenses of treatment also differed. The cost of prescriptions for female patients was, on average, 17% less than that for male patients.

CONCLUSION

The choice of antihypertensive drugs depends on the age and sex of a patient. Prescribing antihypertensive drugs does not fully meet national recommendations. New drugs are gaining ground in the treatment of hypertension. An increase in the cost of treatment will result from this development.

[Hypertensive crises]

The goal of the accurate treatment of an hypertensive crisis is to reduce the critically elevated blood pressure to a safer level, in an hemodynamic point of view, although not necessarily normal. The authors stress that a prompt and correct diagnosis in distinguishing hypertensive emergencies from urgencies, in understanding its pathophysiology and the knowledge of available drugs is essential for a successful management.

[Retrospective studies and prospects of therapy for hypertension]

Future trends in hypertensive treatment have to rely on our past and present experience with antihypertensive drugs as well as on emerging concepts of blood pressure regulation, on which some new drugs in the "pipeline" are based. Early detection of hypertension, before organ manifestations particularly in the heart, the kidney and the vessels occur, remain mandatory since in most of the patients with mild and moderate hypertension the high blood pressure is not diagnosed at all or treated inadequately. Prevention of cardiac, vascular, renal or metabolic complications has always been better for the patient and less costly than their repair or reparation. Our present treatment goals have often not reached far enough. Normalisation of blood pressure demonstrates only surrogate efficacy of our treatment. Our ultimate goal has to be improvement of total or cerebrovascular or cardiovascular and cardiac mortality. Important steps on that road are the prevention or reparation of cardiac hypertrophy, of the increased extracellular matrix and collagen deposition, the conservation of vascular integrity including both coronary and systemic microangiopathy and macroangiopathy. For the patient this means integrated care of his associated disorders that is of coronary artery disease, diabetes mellitus, lipid disorders, overweight and the metabolic syndrome. True health efficacy (= reduction of total or cerebro- and cardiovascular mortality) has been demonstrated so far only by blood pressure reduction with diuretics (thiazides) and beta-blockers in long term studies, whereas sufficient surrogate efficacy, the lowering of blood pressure, has been demonstrated with almost all the others drugs either in mono- or in combinationtherapy. Together with ACE-inhibitors, which have demonstrated their prognostic value in patients with heart failure of different causes, thiazides (as the most representative diuretic) and betablockade can be considered first line drugs in the treatment of hypertension. Long-term mortality trials for ACE-inhibitors in hypertension are needed, however, to prove that the anticipated benefit from the heart failure megatrials can also be taken for granted for hypertensive patients without coronary artery disease as well. All other drugs should not or not yet be considered first line medication, although treatment behavior in the US and in Europe shows wide-spread use of calcium antagonists in short- and long-acting dihydropyridine type hypertensive patients. No peer reviewed journal has so far published a randomized double-blind trial with the endpoint of total or cardiovascular mortality in hypertension using calcium antagonists. A recent case control study, as well as the preliminary data from MIDAS and GLANT, for which event rates are available in abstract form, suggest that short acting calcium-antagonists of the dihydropyridine type, though controlling blood pressure well, are not reducing mortality but show a trend to increase cardiovascular events particularly when given in higher doses. In contrast the unpublished data from a Chinese megatrial with dihydropyridines (STONE) demonstrate effective blood pressure reduction and benefit in mortality in a population that differs from patients in Europe and in the USA because of the low prevalence of coronary artery disease. No randomized, double blindly acquired data on mortality as the primary end of antihypertensive treatment are yet available for verapamil, diltiazem and the new class of longer acting calciumantagonists. Only when speculating from trials with calcium antagonists in coronary artery disease e.g. the DAVIT II study, one could imagine so far that prognostic benefit may be expected from drugs that do not or very little activate the adrenergic and the renin-angiotensin-aldosterone system and the baroreceptors and reduce or at least maintain heart rate. The need for double blind, randomized trials with the different Ca-antagonists is obvious, before a further w

Nonemergent hypertension. New perspectives for the emergency medicine physician

The emergency medicine physician must evaluate and treat hypertensive patients in a variety of contexts, ranging from the compliant patient with well-controlled blood pressure who presents for an unrelated problem, to the patient with asymptomatic blood pressure elevation, to the patient with a true hypertensive urgency or emergency. Recently, the approach to the treatment of adult hypertension has been modified to take into account advances in the understanding of individual patient risk factors and relative risk of cardiovascular complications. Additionally, no data currently exist that show a benefit to acutely lowering the blood pressure of asymptomatic patients with severe blood pressure elevation, but there is data to suggest that it may be harmful, especially in patients with cardiovascular risk factors. From this perspective, the authors define hypertensive urgency and make recommendations for more careful deliberation in management decisions. This article, along with the article on hypertensive emergencies in this issue, provides an approach to the patient presenting to the emergency department with hypertension, elevated blood pressure, or both.

[Hypertension in old age]

Hypertension occurs in 50% of the elderly persons in industrialized societies. This disorder of the regulation of the arterial blood pressure has different manifestations in different age groups. The young hypertensive usually has an increase in cardiac output and a normal peripheral vascular resistance. The elderly patient with hypertension exhibits a decreased cardiac output and an increased peripheral vascular resistance. In the elderly hypertensive there is a progressive anteriolar narrowing and there is hardening of the largest arteries. The vascular disease that contributes to the hypertension in the elderly also causes hypoperfusion of the target organs. During the aging process there is a decrease in cardiac output, glomerular filtration rate, vital capacity, renal plasma flow and maximal cardiac rate. There are changes in the kidneys and the liver that influence the way different medications are handled by the body. The main findings of the Australian, EWPHE, Coope & Warrender, SHEP, STOP-HYP and MRC studies of hypertension in the elderly have been summarized. The intervention studies have proven that the treatment of hypertension in the elderly patient is efficacious and decreases the mortality and morbidity due to coronary and cerebrovascular events. The pharmacologic agents available for the treatment of hypertension in the elderly are the diuretics, beta blockers, vasodilators, calcium-channel blockers, adrenergic blockers and angiotensin converting enzyme inhibitors. The morbidity and mortality benefits derived from antihypertensive trials are greater for the older than for the younger patients. The pharmacologic antihypertensive agents to be used in older patients will also depend upon the presence or not of associated illnesses in which some agents might be harmful or contraindicated.(ABSTRACT TRUNCATED AT 250 WORDS)

[Drug interactions with antihypertensive drugs]

Numerous of pharmacokinetic and pharmacodynamic interactions with antihypertensive drugs have to be considered. In this review, interactions are analysed in the major organ sites of these interactions and in cardiovascular target sites of arterial hypertension, with respect to the major antihypertensive drugs. Many antihypertensive drugs are metabolized in the liver (calcium antagonists, liposoluble beta-blockers, and some ACE-inhibitors) via the cytochrome-oxidase system. Phenytoin, barbiturates, and rifampin can accelerate the breakdown of these drugs; conversely, cimetidine, which inhibits oxidase system, can increase antihypertensive drug levels, resulted in greater therapeutic effect. Hepatic blood flow can be modified by propranolol and nifedipine with opposite effects. When combined with nifedipine the breakdown of propranolol is accelerated because of an increase of hepatic blood flow. In the kidney, some anti-hypertensive agents interact with other cardiovascular drugs by competing for renal clearance; calcium antagonists alter the renal clearance of digoxin, but the mechanism remains unclear. In vascular muscle cells, excess vasodilatation or vasoconstriction can be observed. The combination of an alpha 1-blocking agent with a dihydropyridine can induce hypotension, which is sometimes severe. Non-steroidal antiinflammatory drugs (NSAIDs) are able to lessen the antihypertensive effects of beta-blockers, diuretics and ACE-inhibitors, via vascular prostaglandin inhibition. The cardiac pharmacodynamic interactions of beta-blockers and calcium antagonists, verapamil and diltiazem, at the sino-atrial node, atrio-ventricular node, conduction system and myocardium are well established and must be avoided. The main interactions with beta-blockers concern calcium antagonists, class I antiarrhythmic drugs and NSAIDs.(ABSTRACT TRUNCATED AT 250 WORDS)

Management of the hypertensive patient: a case report

Hypertension is a potentially life-threatening condition that can lead to heart failure, stroke, and kidney disease. Most patients with hypertension can be treated and controlled if they are diagnosed in a timely manner. This case report exemplifies how the dentist can play a key role in the detection of hypertension by simply taking vital signs on all patients. It is incumbent upon us as health-care professionals to understand the causes of hypertension, the therapeutic drugs used and associated side effects, and the potential for drug interactions. The dentist's ability to recognize and appropriately manage hypertension will greatly enhance the health and safety of our patients.

Relevance of plasma noradrenaline concentrations to estimate autonomic effects of antihypertensive drugs

The sympathetic nervous system is important in regulating cardiovascular function. It is therefore of interest to study the influence of antihypertensive drugs on sympathetic nerve activity. For this purpose, measurements of noradrenaline concentrations in forearm venous plasma have often been used. For several reasons, this provides limited information: i) the sympathetic nervous system is highly differentiated, i.e. activity may be high in some organs and low in others; ii) noradrenaline in forearm venous plasma is largely derived from sympathetic activity to the forearm skeletal muscle; iii) plasma noradrenaline concentrations are determined not only by noradrenaline spillover from sympathetic nerve endings, which is related to sympathetic nerve activity, but also by noradrenaline clearance. Under most circumstances plasma noradrenaline concentrations are not high enough to produce hormonal effects. Many types of antihypertensive drugs may cause acute and long-term increases in forearm venous noradrenaline concentrations. The mechanisms underlying these increases are not fully understood but seem to differ between drug classes: Diuretics increase renal noradrenaline spillover; beta-blockers do not affect spillover but reduce total noradrenaline clearance; calcium antagonists and alpha-blockers probably increase noradrenaline spillover, but it is not known which organs are involved, particularly during long-term treatment. ACE inhibitors seem to have a sympatholytic action, which counteract reflex increases in sympathetic nerve activity during blood pressure reduction, and plasma noradrenaline concentrations are generally not affected. To be able to judge the possible clinical consequences of changes in plasma noradrenaline concentrations during chronic antihypertensive treatment, assessments of noradrenaline spillover from individual organs are needed.

New FDA guidelines on the treatment of hypertension: comparison of different therapeutic classes according to trough/peak blood pressure responses

The FDA guidelines, recommending a trough/peak blood pressure response ratio of at least 50%, were formulated with a view to providing a definitive index of duration of action of an antihypertensive drug. The aim was to prevent the use of drug regimens that utilised high doses of drug with the aim of maintaining a significant reduction in blood pressure at the end of the steady state dosage interval. The calculation of trough/peak ratios is subject to significant variability but much of this can be directly attributed to different methodological approaches. However, when conditions are standardised it has been shown that trough/peak ratios are reproducible in individual patients. Trough/peak ratios defined for different antihypertensive drugs often exhibit as many differences within a therapeutic class as between therapeutic classes. Thus there is no single therapeutic class of drugs that offers high trough/peak ratios compared to an alternative class. The possible exception to this are the diuretics which probably all have comparatively high trough/peak ratios although this has never formally been defined. With respect to the beta adrenoceptor antagonists there is discernible discrimination between the once a day agents with betaxolol, bisoprolol and acebutolol all having a longer duration of action as defined by a higher trough/peak response than atenolol. Calcium antagonists show considerable variability in trough/peak ratio between different drugs. In particular the first generation agents, verapamil, nifedipine and diltiazem all had relatively low values. Not all the second generation agents were superior to this and at present only amlodipine and lacidipine and some of the "reformulated" agents meet the recommendations of the Guidelines for once a day drugs.(ABSTRACT TRUNCATED AT 250 WORDS)

What can we expect in antihypertensive drug therapy?

In the present brief survey on new developments in the drug treatment of essential hypertension, the following issues are summarized: the treatment of hypertension in diabetics, patients with left ventricular hypertrophy, and the elderly; new antihypertensive drugs, including a hybrid (multifactorial) antihypertensive drug with both calcium and alpha 1-adrenoceptor antagonistic activity, as well as angiotensin II-receptor antagonists; and finally, gene therapy in hypertension.

Drug therapy for hypertension: where we are, and where we might be heading

The past two decades have witnessed major improvements in antihypertensive drug therapy. Although diuretics and beta-adrenergic antagonists remain the drugs of choice, we now recommend much lower doses than we previously did. This appears to achieve equal blood pressure control while causing fewer side effects. Angiotensin-converting enzyme inhibitors and calcium antagonists are newer, relatively expensive drug classes whose benefits can be exploited in certain subgroups of patients. Whether they will lead to improved outcome in the uncomplicated hypertensive patient remains uncertain. New classes of drugs affecting the renin-angiotensin system are in various stages of development. Again, they have theoretical advantages over those currently available. Still other classes--thromboxane synthase or receptor antagonists and endothelin antagonists--appear promising in animal studies. Finally, in future, it may be possible to cure hypertension by altering a patient's genetic make-up.