28
CHAPTER 6
Hypertension Dr Barry Hoffbrand, DM, FRCP Dr Melvin Ross, FRCGP
SUMMARY 1. Accurate measurement of blood pressure using a regularly serviced sphygmomanometer is essential. 2. Severe hypertension requires early treatment. Uncomplicated mild to moderate hypertension requires repeated blood pressure measurements up to three or four months before the diagnosis is confirmed. 3. Personal and family histories, relevant examination and investigations precede treatment. 4. Initial management should aim at reducing weight, improving diet and exercise, and stopping cigarette and excess alcohol consumption. 5. Patients with other risk factors require drug treatment at an earlier stage and at lower blood pressure levels. Essential hypertension is associated with an increased prevalence of riskfactors which may need attention. 6. Treatment of asymptomatic hypertension should be considered in patients up to the age of 80. 7. First-line treatment: thiazide diuretics and beta blockers, used in the lowest effective doses, are of proven value and acceptability. The former are by far the cheapest antihypertensive drugs. 8. Second-line treatment: if thiazides and beta blockers are contra-indicated or ineffective, ACE inhibitors, calcium antagonists and alpha blockers should be used. With drugs of these classes the absence of adverse cardiovascular metabolic effects is a theoretical advantage but of uncertain
magnitude. 9. Follow-up of patients with borderline levels of raised blood pressure as well as for those on treatment is essential. Introduction The benefits derived from treating severe and moderate hypertension are not in doubt. The results of a meta-analysis of several large controlled studies in mild hypertension have also shown a reduction of 42% in strokes and 14% in coronary heart disease (Collins et al., 1990). Patients up to the age of 80 should be treated and a recent study suggests that the benefits may be evident at even older ages (Dahlof et al., 1991). It is generally agreed that drug treatment is indicated if, on repeated measurements over 3-4 months, the diastolic blood pressure remains at or above 100 mmHg (phase 5) despite adequate non-pharmacological measures (British Hypertension Society Working Party, 1989). It has now been shown that isolated systolic hypertension
(.160 mmHg) in the elderly (>60 years) merits treatment (SHEP Co-operative Research Group, 1991). Most patients with hypertension should be managed by the general practitioner. If specialist advice is required the patient should generally be referred back to the general practitioner's care as soon as possible. Hypertension is not a condition which can be diagnosed in the accident and emergency department, or by doctors seeing patients on one or two occasions, unless there is obvious end organ damage. It is suggested that each practice should have a protocol for screening and treatment, including repeat prescriptions and follow-up. Surveys show that up to 10% of the adult population have a persistent diastolic reading of 100 mmHg or more. Under the 1990 contract many patients are already having their blood pressure measured and an effective management plan is required to ensure they receive adequate treatment with a minimum of side-effects.
Measurement of blood pressure The following guidelines are based on Petrie et al. (1990): 1. Accurate mercury sphygmomanometer, regularly 'serviced'. 2. Adequate bladder size: approximately 12.5 x 33 cm. The 'normal adult' cuff is 12 x 23 cm and is inadequate for obese arms. 3. A relaxed patient with arm supported. 4. Good technique, eg drop in pressure of 2-3 mm/sec. 5. Adequate hearing in the observer. 6. Record phases 1 and 5 (occasionally it may be necessary to record 1, 4 and 5, eg in antenatal care).
History, examination and investigations These would generally be carried out either during the first or second consultation depending on the level of blood pressure. (An isolated raised blood pressure reading does not require a full assessment but the opportunity can be used for general health advice, as indicated, and the patient should be followed up as described later.) A raised diastolic pressure >100 mmHg requires examination and investigation as follows: 1. Full history including smoking, alcohol and prescribed drugs (including the contraceptive pill and hormone replacement therapy) and non-prescribed drugs 2. Family history especially hypertension and coronary heart disease or stroke noting the age of onset (vascular disease in first degree relatives aged 10 mmHg 4. Urine test for protein and sugar 5. Investigations: full blood count, urea and electrolytes, serum creatinine, serum cholesterol, ECG. Severe hypertension Severe hypertension may be confirmed after two or three readings at short intervals. The suggested criteria are: 1. Diastolic > 120 mmHg
* Diabetes (if renal involvement, consider treatment at BP 140/90 mmHg) * Angina pectoris * Systolic pressure >160 mmHg * Person is under 45 years of age * LVH * Raised cholesterol * Afro-Caribbean or African * Family history of stroke or other vascular disease occurring at a relatively early age, eg under 55. No trial has looked prospectively at the above criteria for treatment but there is general agreement that the presence of one or more should lower the threshold blood pressure level for introducing hypotensive medication.
or
2. Evidence of target organ damage, eg fundal changes, unequivocal left ventricular hypertrophy either clinically or on ECG, proteinuria. These patients may require early treatment or referral to a
specialist. Mild to moderate hypertension This should be diagnosed when the diastolic blood pressure is between 100 and 119 mmHg on three or more readings over a 3-4 month period. If the pressure is persistently in the higher part of the range, drug treatment may be considered before 3 months (see also factors under 'Drug treatment').
Non-drug management The place in hypertension management of non-pharmacological measures has been well reviewed (Beilin, 1988). Advice should be offered immediately the initial finding has been confirmed and include the following: 1. Diet to encourage weight loss and lowering of blood cholesterol when necessary. No added salt - although salt restriction to about 80 mmol/day will lower the blood pressure modestly, it is difficult to achieve in practice and seems least effective in mild hypertension (Australian National Health and Medical Research Council Dietary Salt Study Management Committee, 1989). A diet rich in fruit and vegetables may help reduce stroke by providing extra potassium (Swales, 1991). 2. Stop smoking. 3. Reduce alcohol intake - aim for less than 21 units per week in men and 14 units per week in women. 4. Regular exercise.
Objectives The aim is to reduce the diastolic pressure to or below 90 mmHg with either no or minimal side-effects from treatment. After adequate control is obtained, readings should be made at least every six months. At the onset of treatment it should be stressed to the patient that at present treatment must be considered lifelong. In the elderly, other illnesses, other drugs being taken, memory loss and the effect of minor side-effects might affect the decision to start or continue treatment and smaller doses may be adequate. Which drug(s)? The following proposals for drugs to be used and the priority given to them is based on the length of experience, their assessment by controlled long-term trials, their cost and potential adverse reactions. (The costs and common problems associated with antihypertensive drugs are listed in Appendices I and 2; British Hypertension Society Working Party, 1989; Swales, 1990). Diuretics and beta blockers are of proven value in reducing morbidity in large studies and remain the drugs of first choice (British Hypertension Society, 1989). Calcium antagonists and angiotensin converting enzyme (ACE) inhibitors are second-line drugs although they are frequently indicated as first choice where beta blockers and diuretics are contraindicated. Although thiazides and beta blockers may have adverse effects on lipid profiles and glucose tolerance, in practice this is of no clinical significance in the majority of patients. ACE inhibitors (and alpha blockers) may have a beneficial effect on these factors and ACE inhibitors are increasingly used as first-line treatment in diabetic hypertensive patients. Calcium antagonists are neutral in contrast to the adverse metabolic effects of diuretics and beta blockers.
Thiazide diuretics Drug treatment This should be started early in severe hypertension but in uncomplicated mild hypertension treatment will generally be started only when the diastolic is persistently .100 mmHg on repeated measurements over 3 months despite adequate nondrug measures. It may be necessary to start prescribing before 3 months or at a level .95 mmHg in the presence of the following:
Small doses of a thiazide diuretic such as bendrofluazide (2.5 mg and rarely more than 5 mg) are highly costeffective, with minimal side-effects. They are particularly valuable in the elderly, Afro-Caribbean, female and cardiac failure patients. They should be avoided in gout and, if possible, Type 2 diabetes. There is no convincing evidence that the hypokalaemia seen with moderate doses of thiazide diuretics is hazardous or that extra potassium or potassiumretaining diuretics are of any value. It is generally agreed,
30
however, that potassium levels should be kept normal in patients on digoxin. Loop diuretics (frusemide, bumetanide) have little place in the treatment of hypertension with normal renal function. Beta blockers The cardioselective drugs atenolol (25-100 mg daily) and metoprolol (100-400 mg daily) are probably the best choice but all beta blockers are absolutely contra-indicated in anyone with a history of asthma or with heart block. They are of particular value in patients with angina. Relative contraindications include peripheral vascular disease. Diuretic plus beta blocker If a diuretic or beta blocker is not effective alone, the next step is generally to use them together provided there are no contra-indications to the second drug. Calcium antagonists These are of value in patients with angina and they have a particular place in those with co-existent asthma or chronic obstructive airways disease. Examples are nifedipine SR 10-20 mg bd and verapamil 120 mg bd.
Calcium antagonist plus beta blocker The combination of calcium antagonist and beta blocker is effective and several combined preparations are available.
ACE inhibitors ACE inhibitors are of value in patients with cardiac failure and combination with a diuretic is particularly effective and enables a lower dose of the ACE inhibitor to be used. Patients who are already on diuretics should be started on ACE inhibitors with great caution as severe hypotension may be precipitated. It is advisable to stop the diuretics for three days before starting ACE inhibitors or refer to a specialist. They should probably not be started by a general practitioner in patients with renal failure. Patients with peripheral vascular disease have a high incidence of renal artery stenosis when ACE inhibitors can give rise to renal impairment but they are useful drugs in diabetics with hypertension. Renal function (blood urea and/or creatinine) should generally be checked once patients are established on these drugs.
Indications for referral to a specialist Indications for referral are not absolute and will depend on the experience of the practitioner and the views of the patient. They include: * Very high initial findings, eg sustained diastolic reading .130 mmHg * Progressive end-organ damage * Young patient, eg under 40 years of age * Abnormal investigation results suggesting underlying remediable cause for hypertension * Failure to respond to treatment. Follow-up It is recommended that after control is obtained, all patients should have their blood pressure checked by a doctor or practice nurse at least every six months. At this visit the following checks should be carried out: * Recording of blood pressure in the notes or on a hypertension record card * Weight check * Tobacco and alcohol consumption * Assessment of patient compliance * Urea and electrolytes, if on thiazide or ACE inhibitor. If non-attenders are followed up, after adequate explanation many patients will understand the need for regular therapy. It is useful for patients to have a repeat prescription card or computer print-out for any emergency hospital attendance and also for obtaining repeat prescriptions. Most practices will have developed some method for the systematic detection of hypertension, for example regular screening or opportunistic case finding (including patient registration and other health checks). Patients who initially have a raised blood pressure reading which falls during the next three months and also those with a diastolic level over 95 mmHg but under 100 mmuHg should have their blood pressure measured at least annually. It is important to advise patients with hypertension that this may be a familial condition and that their children and other relations should have their blood pressure checked.
1.
2. Third-line drugs Third-line drugs can be added to those being used if the blood pressure control remains unsatisfactory, that is above 90 mmHg, having ensured the patient's compliance with the other medication. Prazosin and methyldopa occasionally have a role. There is currently little enthusiasm for the old 'stepped care' regime of diuretic/beta blocker/vasodilator and more for trying combinations of first- and second-line drugs, replacing those that seem to have had little or no hypotensive effect in the individual patient. New drugs may shortly be due for consideration by general practitioners.
3.
4.
5.
Practice audit When were sphygmomanometers last checked? (a) desktop (b) those in visiting bags What is the proportion of patients with hypertension who have had their blood pressure measured within the last six months? What is the proportion of patients in the 'observation group' (ie those with an initially high blood pressure which falls without treatment and those with persistent blood pressure 95-100 mmHg) who have had their blood pressure measured in the last year? What is the proportion of patients whose treatment has been reviewed within the last year? What is the proportion of new patients who have had initial check-ups and their blood pressure measured?
31
6. What is the proportion of patients not on treatment for raised blood pressure who have had their blood pressure checked in the last three years? 7. What is the proportion of patients on thiazides or ACE inhibitors who have had their urea and electrolytes checked within the last year? 8. In how many hypertensive patients is there an updated record of other risk factors in the general practitioner notes, for example smoking, alcohol consumption?
References Australian National Health and MRC Council Dietary Salt Study Management Committee (1989) Fall in blood pressure with modest reduction in dietary salt intake in mild hypertension. Lancet 333, 399-402. Beilin L J (1988) Non pharmacological control of blood pressure. Clin. Exp. Pharmacol. Physiol. 15, 215-23. British Hypertension Society Working Party (1989) Treating mild hypertension; agreement from the large trials. Report. British Medical Journal 298, 694-8. Collins R, Peto R, MacMahon S et al. (1990) Blood pressure, stroke and coronary heart disease. Part 2. Short term reductions in blood pressure; overview of randomized trials in their epidemiological context. Lancet 335, 827-38. Dahlof B, Lindholm L H, Hansson L et al. (1991) Morbidity and mortality in the Swedish trial in old patients with hypertension (STOP - Hypertension). Lancet 338, 1281-5. Petrie J C, O'Brien E T, Littler W A et al. (1 990) Recommendations on Blood Preessure Measurement. 2nd ed. London, British Medical Journal. SHEP Co-operative Research Group (1991) Prevention of stroke by antihypertensive drug treatment in older person with isolated systolic hypertension. Journal of the American Medical Association 265, 3255-64. Swales J D (1991) Salt substitutes and potassium intake. British Medical Journal 303, 1084-5.
Further reading British Medical Association (1987) ABC of Hypertension. 2nd ed. London. British Medical Journal. Drug and Therapeutics Bulletin. Factfile (British Heart Foundation). Hart J T (1987) Hypertension. Community Control of High Blood Pressure. Edinburgh, Churchill Livingstone. Prescribers 'Journal.
Reading for patients British Medical Association (1987) You and Your Blood Pressure. Family Doctor Publication. Available BMA House, London WC 1. Stuart Pharmaeuticals (1991 ) Down with Blood Pressure. Available from Stuart Pharmaceuticals Ltd, Cheadle, Cheshire SK8 2EG.
APPENDIX 1 The following was the cost to the NHS of eight weeks' supply on a general practitioner's prescription in November 1991. This excludes the pharmacist's professional fee - though the actual costs will rise the relative costs are likely to remain similar.
Bendrofluazide 2.5 mg daily 39p Bendrofluazide 5.0 mg daily 14p* Atenolol 25 mg daily £8.62 Atenolol 50 mg daily £9.62 Atenolol 100 mg daily £13.60 Nifedipine SR 10 mg twice daily £16.68 Nifedipine SR 20 mg twice daily £21.63 Atenolol plus 50 mg daily £21.80 Nifedipine SR 20 mg (Tenif, Beta-adalat, etc) Verapamil 160 mg twice daily £20.98 Enalapril 10 mg daily £22.06 25 mg twice daily Captopril £24.06 *The higher dose of bendrofluazide is slightly cheaper than the lower dose because 5 mg tablets are sold in large pack sizes.
APPENDIX 2 The following is a list of some of the common problems associated with these drugs. Further details are available in the British National FormularY and proprietary drug data cards.
Bendrofluazide and other thiazides: Lethargy, hyperuricaemia/gout, impotence, impaired glucose tolerance, constipation, hypokalaemia. (These side effects can be minimized by use of a low dose eg 2.5 mg of bendrofluazide). Beta blockers: Lethargy, dyspnoea, cold extremities, impotence, rashes, dreams, bradycardia. Not to be used in obstructive airway disease, cardiac failure or brittle diabetics. Nifedipine: Flushing, headache, tachycardia, ankle oedema, nocturia. Verapamil: Less flushing than nifedipine but constipates, negative inotropic effect. Enalapril and captopril: Rash, hypotension, angio-oedema, taste disturbance and cough.
CHAPTER 6
Hypertension Dr Barry Hoffbrand, DM, FRCP Dr Melvin Ross, FRCGP
SUMMARY 1. Accurate measurement of blood pressure using a regularly serviced sphygmomanometer is essential. 2. Severe hypertension requires early treatment. Uncomplicated mild to moderate hypertension requires repeated blood pressure measurements up to three or four months before the diagnosis is confirmed. 3. Personal and family histories, relevant examination and investigations precede treatment. 4. Initial management should aim at reducing weight, improving diet and exercise, and stopping cigarette and excess alcohol consumption. 5. Patients with other risk factors require drug treatment at an earlier stage and at lower blood pressure levels. Essential hypertension is associated with an increased prevalence of riskfactors which may need attention. 6. Treatment of asymptomatic hypertension should be considered in patients up to the age of 80. 7. First-line treatment: thiazide diuretics and beta blockers, used in the lowest effective doses, are of proven value and acceptability. The former are by far the cheapest antihypertensive drugs. 8. Second-line treatment: if thiazides and beta blockers are contra-indicated or ineffective, ACE inhibitors, calcium antagonists and alpha blockers should be used. With drugs of these classes the absence of adverse cardiovascular metabolic effects is a theoretical advantage but of uncertain
magnitude. 9. Follow-up of patients with borderline levels of raised blood pressure as well as for those on treatment is essential. Introduction The benefits derived from treating severe and moderate hypertension are not in doubt. The results of a meta-analysis of several large controlled studies in mild hypertension have also shown a reduction of 42% in strokes and 14% in coronary heart disease (Collins et al., 1990). Patients up to the age of 80 should be treated and a recent study suggests that the benefits may be evident at even older ages (Dahlof et al., 1991). It is generally agreed that drug treatment is indicated if, on repeated measurements over 3-4 months, the diastolic blood pressure remains at or above 100 mmHg (phase 5) despite adequate non-pharmacological measures (British Hypertension Society Working Party, 1989). It has now been shown that isolated systolic hypertension
(.160 mmHg) in the elderly (>60 years) merits treatment (SHEP Co-operative Research Group, 1991). Most patients with hypertension should be managed by the general practitioner. If specialist advice is required the patient should generally be referred back to the general practitioner's care as soon as possible. Hypertension is not a condition which can be diagnosed in the accident and emergency department, or by doctors seeing patients on one or two occasions, unless there is obvious end organ damage. It is suggested that each practice should have a protocol for screening and treatment, including repeat prescriptions and follow-up. Surveys show that up to 10% of the adult population have a persistent diastolic reading of 100 mmHg or more. Under the 1990 contract many patients are already having their blood pressure measured and an effective management plan is required to ensure they receive adequate treatment with a minimum of side-effects.
Measurement of blood pressure The following guidelines are based on Petrie et al. (1990): 1. Accurate mercury sphygmomanometer, regularly 'serviced'. 2. Adequate bladder size: approximately 12.5 x 33 cm. The 'normal adult' cuff is 12 x 23 cm and is inadequate for obese arms. 3. A relaxed patient with arm supported. 4. Good technique, eg drop in pressure of 2-3 mm/sec. 5. Adequate hearing in the observer. 6. Record phases 1 and 5 (occasionally it may be necessary to record 1, 4 and 5, eg in antenatal care).
History, examination and investigations These would generally be carried out either during the first or second consultation depending on the level of blood pressure. (An isolated raised blood pressure reading does not require a full assessment but the opportunity can be used for general health advice, as indicated, and the patient should be followed up as described later.) A raised diastolic pressure >100 mmHg requires examination and investigation as follows: 1. Full history including smoking, alcohol and prescribed drugs (including the contraceptive pill and hormone replacement therapy) and non-prescribed drugs 2. Family history especially hypertension and coronary heart disease or stroke noting the age of onset (vascular disease in first degree relatives aged 10 mmHg 4. Urine test for protein and sugar 5. Investigations: full blood count, urea and electrolytes, serum creatinine, serum cholesterol, ECG. Severe hypertension Severe hypertension may be confirmed after two or three readings at short intervals. The suggested criteria are: 1. Diastolic > 120 mmHg
* Diabetes (if renal involvement, consider treatment at BP 140/90 mmHg) * Angina pectoris * Systolic pressure >160 mmHg * Person is under 45 years of age * LVH * Raised cholesterol * Afro-Caribbean or African * Family history of stroke or other vascular disease occurring at a relatively early age, eg under 55. No trial has looked prospectively at the above criteria for treatment but there is general agreement that the presence of one or more should lower the threshold blood pressure level for introducing hypotensive medication.
or
2. Evidence of target organ damage, eg fundal changes, unequivocal left ventricular hypertrophy either clinically or on ECG, proteinuria. These patients may require early treatment or referral to a
specialist. Mild to moderate hypertension This should be diagnosed when the diastolic blood pressure is between 100 and 119 mmHg on three or more readings over a 3-4 month period. If the pressure is persistently in the higher part of the range, drug treatment may be considered before 3 months (see also factors under 'Drug treatment').
Non-drug management The place in hypertension management of non-pharmacological measures has been well reviewed (Beilin, 1988). Advice should be offered immediately the initial finding has been confirmed and include the following: 1. Diet to encourage weight loss and lowering of blood cholesterol when necessary. No added salt - although salt restriction to about 80 mmol/day will lower the blood pressure modestly, it is difficult to achieve in practice and seems least effective in mild hypertension (Australian National Health and Medical Research Council Dietary Salt Study Management Committee, 1989). A diet rich in fruit and vegetables may help reduce stroke by providing extra potassium (Swales, 1991). 2. Stop smoking. 3. Reduce alcohol intake - aim for less than 21 units per week in men and 14 units per week in women. 4. Regular exercise.
Objectives The aim is to reduce the diastolic pressure to or below 90 mmHg with either no or minimal side-effects from treatment. After adequate control is obtained, readings should be made at least every six months. At the onset of treatment it should be stressed to the patient that at present treatment must be considered lifelong. In the elderly, other illnesses, other drugs being taken, memory loss and the effect of minor side-effects might affect the decision to start or continue treatment and smaller doses may be adequate. Which drug(s)? The following proposals for drugs to be used and the priority given to them is based on the length of experience, their assessment by controlled long-term trials, their cost and potential adverse reactions. (The costs and common problems associated with antihypertensive drugs are listed in Appendices I and 2; British Hypertension Society Working Party, 1989; Swales, 1990). Diuretics and beta blockers are of proven value in reducing morbidity in large studies and remain the drugs of first choice (British Hypertension Society, 1989). Calcium antagonists and angiotensin converting enzyme (ACE) inhibitors are second-line drugs although they are frequently indicated as first choice where beta blockers and diuretics are contraindicated. Although thiazides and beta blockers may have adverse effects on lipid profiles and glucose tolerance, in practice this is of no clinical significance in the majority of patients. ACE inhibitors (and alpha blockers) may have a beneficial effect on these factors and ACE inhibitors are increasingly used as first-line treatment in diabetic hypertensive patients. Calcium antagonists are neutral in contrast to the adverse metabolic effects of diuretics and beta blockers.
Thiazide diuretics Drug treatment This should be started early in severe hypertension but in uncomplicated mild hypertension treatment will generally be started only when the diastolic is persistently .100 mmHg on repeated measurements over 3 months despite adequate nondrug measures. It may be necessary to start prescribing before 3 months or at a level .95 mmHg in the presence of the following:
Small doses of a thiazide diuretic such as bendrofluazide (2.5 mg and rarely more than 5 mg) are highly costeffective, with minimal side-effects. They are particularly valuable in the elderly, Afro-Caribbean, female and cardiac failure patients. They should be avoided in gout and, if possible, Type 2 diabetes. There is no convincing evidence that the hypokalaemia seen with moderate doses of thiazide diuretics is hazardous or that extra potassium or potassiumretaining diuretics are of any value. It is generally agreed,
30
however, that potassium levels should be kept normal in patients on digoxin. Loop diuretics (frusemide, bumetanide) have little place in the treatment of hypertension with normal renal function. Beta blockers The cardioselective drugs atenolol (25-100 mg daily) and metoprolol (100-400 mg daily) are probably the best choice but all beta blockers are absolutely contra-indicated in anyone with a history of asthma or with heart block. They are of particular value in patients with angina. Relative contraindications include peripheral vascular disease. Diuretic plus beta blocker If a diuretic or beta blocker is not effective alone, the next step is generally to use them together provided there are no contra-indications to the second drug. Calcium antagonists These are of value in patients with angina and they have a particular place in those with co-existent asthma or chronic obstructive airways disease. Examples are nifedipine SR 10-20 mg bd and verapamil 120 mg bd.
Calcium antagonist plus beta blocker The combination of calcium antagonist and beta blocker is effective and several combined preparations are available.
ACE inhibitors ACE inhibitors are of value in patients with cardiac failure and combination with a diuretic is particularly effective and enables a lower dose of the ACE inhibitor to be used. Patients who are already on diuretics should be started on ACE inhibitors with great caution as severe hypotension may be precipitated. It is advisable to stop the diuretics for three days before starting ACE inhibitors or refer to a specialist. They should probably not be started by a general practitioner in patients with renal failure. Patients with peripheral vascular disease have a high incidence of renal artery stenosis when ACE inhibitors can give rise to renal impairment but they are useful drugs in diabetics with hypertension. Renal function (blood urea and/or creatinine) should generally be checked once patients are established on these drugs.
Indications for referral to a specialist Indications for referral are not absolute and will depend on the experience of the practitioner and the views of the patient. They include: * Very high initial findings, eg sustained diastolic reading .130 mmHg * Progressive end-organ damage * Young patient, eg under 40 years of age * Abnormal investigation results suggesting underlying remediable cause for hypertension * Failure to respond to treatment. Follow-up It is recommended that after control is obtained, all patients should have their blood pressure checked by a doctor or practice nurse at least every six months. At this visit the following checks should be carried out: * Recording of blood pressure in the notes or on a hypertension record card * Weight check * Tobacco and alcohol consumption * Assessment of patient compliance * Urea and electrolytes, if on thiazide or ACE inhibitor. If non-attenders are followed up, after adequate explanation many patients will understand the need for regular therapy. It is useful for patients to have a repeat prescription card or computer print-out for any emergency hospital attendance and also for obtaining repeat prescriptions. Most practices will have developed some method for the systematic detection of hypertension, for example regular screening or opportunistic case finding (including patient registration and other health checks). Patients who initially have a raised blood pressure reading which falls during the next three months and also those with a diastolic level over 95 mmHg but under 100 mmuHg should have their blood pressure measured at least annually. It is important to advise patients with hypertension that this may be a familial condition and that their children and other relations should have their blood pressure checked.
1.
2. Third-line drugs Third-line drugs can be added to those being used if the blood pressure control remains unsatisfactory, that is above 90 mmHg, having ensured the patient's compliance with the other medication. Prazosin and methyldopa occasionally have a role. There is currently little enthusiasm for the old 'stepped care' regime of diuretic/beta blocker/vasodilator and more for trying combinations of first- and second-line drugs, replacing those that seem to have had little or no hypotensive effect in the individual patient. New drugs may shortly be due for consideration by general practitioners.
3.
4.
5.
Practice audit When were sphygmomanometers last checked? (a) desktop (b) those in visiting bags What is the proportion of patients with hypertension who have had their blood pressure measured within the last six months? What is the proportion of patients in the 'observation group' (ie those with an initially high blood pressure which falls without treatment and those with persistent blood pressure 95-100 mmHg) who have had their blood pressure measured in the last year? What is the proportion of patients whose treatment has been reviewed within the last year? What is the proportion of new patients who have had initial check-ups and their blood pressure measured?
31
6. What is the proportion of patients not on treatment for raised blood pressure who have had their blood pressure checked in the last three years? 7. What is the proportion of patients on thiazides or ACE inhibitors who have had their urea and electrolytes checked within the last year? 8. In how many hypertensive patients is there an updated record of other risk factors in the general practitioner notes, for example smoking, alcohol consumption?
References Australian National Health and MRC Council Dietary Salt Study Management Committee (1989) Fall in blood pressure with modest reduction in dietary salt intake in mild hypertension. Lancet 333, 399-402. Beilin L J (1988) Non pharmacological control of blood pressure. Clin. Exp. Pharmacol. Physiol. 15, 215-23. British Hypertension Society Working Party (1989) Treating mild hypertension; agreement from the large trials. Report. British Medical Journal 298, 694-8. Collins R, Peto R, MacMahon S et al. (1990) Blood pressure, stroke and coronary heart disease. Part 2. Short term reductions in blood pressure; overview of randomized trials in their epidemiological context. Lancet 335, 827-38. Dahlof B, Lindholm L H, Hansson L et al. (1991) Morbidity and mortality in the Swedish trial in old patients with hypertension (STOP - Hypertension). Lancet 338, 1281-5. Petrie J C, O'Brien E T, Littler W A et al. (1 990) Recommendations on Blood Preessure Measurement. 2nd ed. London, British Medical Journal. SHEP Co-operative Research Group (1991) Prevention of stroke by antihypertensive drug treatment in older person with isolated systolic hypertension. Journal of the American Medical Association 265, 3255-64. Swales J D (1991) Salt substitutes and potassium intake. British Medical Journal 303, 1084-5.
Further reading British Medical Association (1987) ABC of Hypertension. 2nd ed. London. British Medical Journal. Drug and Therapeutics Bulletin. Factfile (British Heart Foundation). Hart J T (1987) Hypertension. Community Control of High Blood Pressure. Edinburgh, Churchill Livingstone. Prescribers 'Journal.
Reading for patients British Medical Association (1987) You and Your Blood Pressure. Family Doctor Publication. Available BMA House, London WC 1. Stuart Pharmaeuticals (1991 ) Down with Blood Pressure. Available from Stuart Pharmaceuticals Ltd, Cheadle, Cheshire SK8 2EG.
APPENDIX 1 The following was the cost to the NHS of eight weeks' supply on a general practitioner's prescription in November 1991. This excludes the pharmacist's professional fee - though the actual costs will rise the relative costs are likely to remain similar.
Bendrofluazide 2.5 mg daily 39p Bendrofluazide 5.0 mg daily 14p* Atenolol 25 mg daily £8.62 Atenolol 50 mg daily £9.62 Atenolol 100 mg daily £13.60 Nifedipine SR 10 mg twice daily £16.68 Nifedipine SR 20 mg twice daily £21.63 Atenolol plus 50 mg daily £21.80 Nifedipine SR 20 mg (Tenif, Beta-adalat, etc) Verapamil 160 mg twice daily £20.98 Enalapril 10 mg daily £22.06 25 mg twice daily Captopril £24.06 *The higher dose of bendrofluazide is slightly cheaper than the lower dose because 5 mg tablets are sold in large pack sizes.
APPENDIX 2 The following is a list of some of the common problems associated with these drugs. Further details are available in the British National FormularY and proprietary drug data cards.
Bendrofluazide and other thiazides: Lethargy, hyperuricaemia/gout, impotence, impaired glucose tolerance, constipation, hypokalaemia. (These side effects can be minimized by use of a low dose eg 2.5 mg of bendrofluazide). Beta blockers: Lethargy, dyspnoea, cold extremities, impotence, rashes, dreams, bradycardia. Not to be used in obstructive airway disease, cardiac failure or brittle diabetics. Nifedipine: Flushing, headache, tachycardia, ankle oedema, nocturia. Verapamil: Less flushing than nifedipine but constipates, negative inotropic effect. Enalapril and captopril: Rash, hypotension, angio-oedema, taste disturbance and cough.
