Long-term management and emergency response of hypertension: individual differences in achieving target blood pressure, regulation of morning blood pressure surge and strategies for dealing with missed doses.

If blood pressure hasn't reached the desired level after several days of medication, should the medication be adjusted? Currently, long-acting formulations of antihypertensive drugs are recommended. These drugs take a longer time to achieve optimal blood pressure reduction. For example, ACE inhibitors require 3-4 weeks. ARBs require even longer. Long-acting calcium channel blockers such as amlodipine (Norvasc) begin to lower blood pressure after one week of use, with maximum blood pressure reduction occurring after 4-6 weeks. Therefore, if blood pressure doesn't reach the ideal level after a few days of taking these medications, it doesn't mean these drugs are ineffective and should be frequently changed to other medications.

Will taking antihypertensive drugs cause diastolic blood pressure to drop too low in patients with isolated systolic hypertension?

Many elderly hypertensive patients are characterized by isolated systolic hypertension, meaning their systolic blood pressure is elevated to or exceeds the diagnostic criteria for hypertension, while their diastolic blood pressure is normal or even low. This type of hypertension is called isolated systolic hypertension. Some patients have low diastolic blood pressure and worry that their antihypertensive medications might lower their already low diastolic pressure even further, while also increasing their pulse pressure. Patients don't need to worry excessively about this. Although antihypertensive medications affect both systolic and diastolic blood pressure, they primarily affect systolic pressure. Furthermore, the body has a self-regulating function for blood pressure and generally won't lower it too much. The extent to which antihypertensive medications lower blood pressure depends on the baseline blood pressure level before medication. The higher the baseline blood pressure level, the greater the decrease after medication, and vice versa. For example, an elderly patient with a pre-medication blood pressure of 170/80 mmHg and a pulse pressure of 90 mmHg might experience a 40 mmHg decrease in systolic blood pressure to 130 mmHg and a diastolic blood pressure to 70 mmHg after taking antihypertensive medication. The pulse pressure would actually decrease to 60 mmHg, therefore, the diastolic blood pressure wouldn't become excessively low.

Should blood pressure targets be adjusted for each individual patient with hypertension?

The optimal blood pressure level depends on many factors, including the patient's age, the severity of hypertension, the presence of comorbidities, and other medical conditions. Therefore, it varies from person to person.

① Generally, hypertensive patients without serious comorbidities can lower their blood pressure to the normal range, i.e., 140/90 mmHg.

② For patients with hypertension complicated by diabetes, kidney damage, dyslipidemia, or who smoke, the target blood pressure is below 130/80 mmHg. Those with kidney disease and significant proteinuria should aim for below 125/75 mmHg.

③ For elderly patients with isolated systolic hypertension, my country's hypertension prevention and treatment guidelines indicate that lowering systolic blood pressure to 140-150 mmHg is also acceptable. The reasoning is that lowering systolic blood pressure is not as easy for the elderly; the success rate of lowering it below 140 mmHg is only about 60%, and their diastolic blood pressure is often normal or low. Overemphasizing lowering systolic blood pressure to normal levels may lead to excessively low diastolic blood pressure. If it falls below 60-70 mmHg, it may affect organs such as the heart and brain.

④ If the disease has a long duration and is complicated by coronary heart disease, diastolic blood pressure should not be lowered below 90 mmHg to avoid inducing acute myocardial infarction.

⑤ If there is insufficient blood supply to the brain or renal insufficiency, blood pressure should not be lowered too much and should be lowered gradually.

⑥ For children and adolescents with hypertension, diastolic blood pressure should be controlled below 90 mmHg. Antihypertensive treatment should not be too rapid; lowering blood pressure to normal levels within weeks or months is sufficient. The focus of treatment should be on identifying the underlying cause of hypertension.

High blood pressure upon waking (morning peak): Should antihypertensive medication be taken at night? Many patients, who have had hypertension for years, have normal daytime blood pressure after taking medication, but their morning blood pressure consistently reaches 150-160/90-95 mmHg. This raises the question of whether they should take antihypertensive medication before bed.

Generally speaking, daytime blood pressure is higher than nighttime blood pressure, and daytime blood pressure fluctuates more significantly, especially systolic blood pressure. Systolic blood pressure reaches its lowest point between 2 and 3 AM, then begins to rise. Upon waking and engaging in activity in the morning, blood pressure rises rapidly. The first peak of systolic blood pressure is reached between 8 and 9 AM, known as the morning peak, and it may be slightly higher between 5 and 6 PM, marking the second peak, after which it begins to decline slowly. Some advocate that for these patients, if taking long-acting medications, antihypertensive medication should be taken once every morning. However, the effective effect of long-acting formulations does not last 24 hours. Therefore, the drug's activity level is very low after waking up the next day, resulting in a weaker effect on the morning blood pressure peak. Thus, it is recommended that those whose nighttime blood pressure drops by less than 10% use long-acting formulations, taking a single dose every night to ensure a certain level of blood drug concentration the next morning. Those whose nighttime blood pressure drops by more than 20% should avoid taking short-acting antihypertensive drugs at night; a single morning dose of long-acting formulation may be more effective.

When is the best time of day to take antihypertensive medication?

Human blood pressure fluctuates according to a certain pattern. Under normal circumstances, blood pressure changes cyclically over 24 hours. Upon waking in the morning, blood pressure shows a continuous upward trend, peaking between 8 and 11 am; then gradually decreases, rising again between 3 and 6 pm. As night falls, blood pressure decreases again, showing a continuous downward trend after falling asleep. Between midnight and waking, blood pressure fluctuates slightly. These two periods of high and low blood pressure are the dangerous periods for hypertension. The timing of taking antihypertensive medication should be determined according to the diurnal rhythm of blood pressure.

① Long-acting formulation: Take once daily upon waking or before bedtime.

② Intermediate-acting formulation: Take once each at 6-7 AM and 2 PM.

③ Short-acting formulation: Take once each at 6-7 AM, 1-2 PM, and 6-7 PM.

Why should short-acting antihypertensive drugs not be taken before bedtime? During sleep, blood pressure naturally decreases by 20%, with the most significant drop occurring two hours after falling asleep. Many short-acting antihypertensive drugs reach peak blood concentration two hours after administration. Therefore, taking a short-acting antihypertensive drug before bedtime can cause a sudden drop in blood pressure due to the combined effects of these two effects. This results in reduced blood perfusion to vital organs, increased blood viscosity, and a higher risk of thrombosis, potentially leading to stroke, myocardial infarction, angina, etc.

What are the characteristics of short-acting, intermediate-acting, and long-acting antihypertensive drugs?

The duration of action of antihypertensive drugs is assessed based on the time the drug maintains its effective effect in the blood.

① Short-acting antihypertensive drugs: These generally maintain their effect for 5-8 hours. Commonly used drugs like nifedipine last about 5 hours, and captopril about 6 hours. Therefore, they must be taken three times a day to ensure effective blood pressure control. While their duration of action is short, their onset of action is rapid; for example, nifedipine takes only 3-15 minutes, and captopril takes 15-30 minutes. Therefore, these drugs are often used as emergency medications in cases of sudden increases in blood pressure.

② Intermediate-acting antihypertensive drugs: These maintain their effect in the blood for 10-12 hours. For example, nifedipine extended-release tablets maintain a minimum effective blood concentration for more than 12 hours after administration. Nifedipine can maintain its effect for 6-15 hours, and enalapril for about 11 hours. These drugs can be taken twice a day.

③ Long-acting antihypertensive drugs: These maintain their antihypertensive effect for more than 24 hours. Amlodipine (35-50 hours) and perindopril (24 hours) have the longest duration of action, but these drugs also take a long time to reach a stable blood pressure-lowering effect, generally 4-7 days. These medications only need to be taken once daily.

What should I do if I miss a dose of my antihypertensive medication? Antihypertensive drugs are divided into short-acting and long-acting types, and the treatment should differ depending on the duration of the missed dose.

Short-acting antihypertensive drugs: The effective concentration in the blood is maintained for a short time after administration, so they are generally taken 3-4 times a day. Missing a dose of these drugs often causes a rise in blood pressure. If you miss a dose in the evening, it's not a big problem because the body's activity level tends to be lower, and blood pressure is relatively stable or even decreased, so there's no need to deliberately take a make-up dose. However, if you miss a dose during the day, blood pressure may fluctuate more significantly due to factors such as emotions and physical activity, and you should take the make-up dose as needed.