INITIATION AND MONITORING
OF ANTIHYPERTENSIVE
THERAPY

Values and Achievements of Antihypertensive Therapy

1. Marked fall in overall and specially cardiovscular mortality.

2. Striking decrease in cerebrovascular accidents: more than 42% reduction in stroke.

3. Virtual disappearance of hypertensive heart failure.

4. Virtual disappearance of malignant hypertension.

5. Diminution in the risk of dissecting aneurysm.

6. Significant protection from progressive renal failure.

7. Reduction in diabetic vascular complications.

8. Possibly delay in the development of ischemic heart disease: 14-27% reduction in coronary heart disease.

Initiation of Antihypertensive Therapy

A. Diagnosis of Hypertension

1. To be established only after repeated blood pressure measurements, the milder the hypertension, the greater the number of blood pressure readings necessary.

2. For mild hypertension six blood pressure measurements and same number of visits are recommended over a period of 4-6 months.

3. An average diastolic pressure of 90 mmHg is required for diagnosing hypertension regardless of age.

4. If mean diastolic blood pressure is > 100 mmHg and there is

nitiation & Monitoring of Antihypertensive Therapy

cardiovascular risk factor or target organ damage start antihypertensive drugs with lifestyle modification.

5. Try non-pharmacologic therapy for approximately six months if mean diastolic pressure is 90-100 in absence of cardiovascular risk factor or terget organ damage. If diastolic pressure of 95 mmHg is not achieved start drugs.

Threshold Blood Pressure for Initiation of Drug Therapy in Uncomplicated Hypertension without Other Rrisk Factors

B. Antihypertensive Drugs

General Guidelines

1. Many antihypertensive drugs require a period of one to two months to achieve their maximal hypotensive action. Unless it is urgent, do not alter the drug regimen befor the passage of at least 2-4 weeks.

2. Dosing intervals affects compliance. Dosing more often than twice daily is associated with decreased compliance.

3. Do not use initial choice drugs with high incidence of side effects such as fatigue, sedation, headache, impotence. Hypertension is a disease without symptoms, drug therapy should not produce symptoms.

4. Choose agents that can also treat disease that might co-exist with

nitiation & Monitoring of Antihypertensive Therapy

hypertension such as coronary disease, heart failure, arrhythmias, migrain.

5. Cost is important consideration since drugs will be given for many years and possibly indefinitely. Make sure that patient can afford medications.

6. In mild and moderate hypertension start with a single drug at a low dose and increase the dose after 2-4 weeks.

7. When using drug combinations or adding an additional drug, it should be from a different pharmacologic group.

Recommended drug combinations

1. Diuretic + ACE inhibitor .

2. Diuretic + beta- blocker.

3. Diuretic + sympatholytic .

4. Calcium antagonist + ACE inhibitor.

5. Dihydropyridine calcium antagonist + beta- blocker.

Always consider the patient's total cardiovascular risk profile, such as diabetes, dyslipidemia when starting and choosing therapy, and the target blood poressure i.e. reduce blood pressure to what level. See table on target blood pressure. The presence of diabetes requires early and aggressive blood pressure lowering.

Recommendations for Firstline Drug Therapy

in Uncomplicated Hypertension

Initiation & Monitoring of Antihypertensive Therapy

Factors Influencing Choice of First Drug

1. Age.

2. Target organ damage.

3. Presence of other cardiovascular risk factors.

4. Concomitant disease.

5. Lifestyle.

6. Socio- economic status.

7. Possible pathophysiologic mechanism (chapter 2).

C. Starting Drug Therapy

1. Goals

1. Achieving and maintaining arterial pressure below 140 mmHg systolic pressure and 90 mmHg diastolic pressure.In diabetic patient or in presence of renal impairement , the target BP is less than 130/85 mmHg. See table on target blood pressure to achieve during antihypertensive treatment.

2. Concurrently controlling other modifiable cardiovascular risk factors.

2. Guidelines

1. Lifestyle modifications are used as adjunctive therapy for hypertension.

2. Period of observation is necessary before starting drug therapy unless systolic pressure is 200mmHg or greater and/ or diastolic pressure 120 mmHg or greater or there is evidence of target organ damage, these conditions require immediate drug intervention.

3. In absence of other cardiovascular risk factors or TOD, initiate treatment if blood pressure remains at or above 150-95 to 140/90 mmHg during 12 months period despite life style modifications.

4. If diastolic blood pressure ranges 90-94 mmHg and systolic pressure 140-149 mmHg in absence of cardiovascular risk factors, drug

Initiation & Monitoring of Antihypertensive Therapy

herapy may not be given. Only follow-up and reinforce lifestyle modification. Careful follow up at 3-6 months intervals is needed in these patients because of the risk of progressing to higher pressure. Clinical judgement is needed to assess overall risk profile. 5. If there is target organ damage and diastolic in the range of the rang of 90-94 mmHg over a period 3 months start drug therapy.

6. If diastolic blood pressure is above 90 mmHg on some occasions but not on others, patient should be assessed yearly. If blood pressures > 140/90 mmHg in a single measurement reassures the patient that one elevated reading does not mean hypertension but follow up, and observation is necessary.

7. Duration of observation period and frequency of clinic or office visits depends upon:

a. Level of blood pressure.

b. Presence of target organ change or other cariovascular risk factors.

Risk Stratification and Treatment (JNC-VI)

Target Blood Pressures (mmHg) to Achieve

Initiation & Monitoring of Antihypertensive Therapy

ISH: International Society of Hypertension

BHS: British Hypertension Society

Stages I and II Hypertension

1. Diastolic blood pressure 90-109 mmHg, systolic blood pressure 140-180 mmHg.

2. Drugs of first choice: diuretics or beta blockers.

· Alterantive drugs: Calcium antagonists, ACE inhibitors, sympatholytics, ARBs.

· Monotherapy with any of these agents can achieve control of hypertension (DBP < 90 mmHg) in approximately half of the patients in this category.

· Preference and pharmacologic selection depends upon:

a. Age.

b. Race.

c. Patient classification (see chapter 2).

d. Presence of special indications to specific drug.

3. Start with small dose.

Initiation & Monitoring of Antihypertensive Therapy

4. If after one to two months the response to initial therapy is inadequate and there are no significant side effects, you have three options: 1. Increase the dose of the first drug.

2. Stop the first drug and substitute an agent from another group.

3. Add a second drug from another group.

5. If the addition of a second agent produces a satisfactory blood pressure control, an attempt to withdraw the first agent may be considered.

6. After blood pressure is reduced to goal levels maintain doses of antihypertensive drug.

Stage III Hypertension

1. DBP > 110 mmHg, SBP > 180 mmHg.

2. Monotherapy can be tried in some patients.

3. Majority of patients need addition of a second or a third agent after a short interval if control is not achieved.

4. Intervals between changes in regimen should be shortened.

5. In many patients it may be necessary to start treatment with more than one agent.

Initiation & Monitoring of Antihypertensive Therapy

FOLLOW-UP Recommendation for Follow-Up Based on Initial Set of

Blood Pressure Measurement

A. No Previous History of High Blood Pressure

*Based on the average of at least two blood pressure measurements. If systolic and diastolic categories are different follow recommendations for the shorter time follow up.

Initiation & Monitoring of Antihypertensive Therapy

B. Patients with Diagnosis and/or Being Treated for High Blood Pressure

* Clinical judgement is required when interpreting blood pressure reading and recommended action: Consider level of blood pressure, target organ damage and cardiovascular risk factors.

Step-Down Therapy

· After blood pressure has been effectively controlled (< 140/90 mmHg) for one year and at least on four visits, it may by possible to reduce antihypertensive drug therapy in a slow and progressive manner (JNC-Guidelines), in patients with no TOD or other risk factors.

· This approach is specially successful in patients who are following lifestyle treatment recommendations. Some can maintain normal blood pressure levels with less or no medications.

· Blood pressure usually rises again to hypertensive levels sometimes months or years after discontinuation of drugs. Regular and close follow up is mandatory.

· Possible mechanisms of normalization of blood pressure due to long drug treatment.

1. Arterial barorefelx reset to normal pressure levels.

2. Regression of structural components of hypertension such as myocardial and vascular hypertrophy.

· Initiation & Monitoring of Antihypertensive Therapy

Some individuals are wrongly diagnosed as having mild hypertension and would have become normotensive after withdrawal of active treatment. 30% of patients diagnosed with mild hypertension showed decline to normal pressure levels when given palcebo alone for several months to years. Blood pressure levels at initial or first visit to the doctor’s office are generally higher than in subsequent visits. Generally blood pressure declines gradually during the initial four months of follow-up and with repeated measurements without active therapy. · 15% of patients whose hypertension was well controlled on medications for five years have remained normotensive for up to five years after discontinuation of therapy.

Cost-Effective Treatment of Hypertension

Verify the diagnosis: Confine treatment to true hypertensives.

· Use total-risk concept: Provide guidance on whether to treat milder forms of hypertension. Look for target organ damage and concomitant risk factors.

· Optimize drug use and utilize drugs efficiently: Careful selecting and if necessary, changing initial therapies.

It is likely that many patients on multiple drug therapy are, in fact, receiving real benefit from only one or two of these drugs.

Modified after Swedish recommendations.

BB: Beta adrenergic blockers; ACE-I: Angioitensin converting enzyme 

Inhibitor; LAD Ca B: Long acting dihydropyridine Ca Channel blockers.