Guidelines for Aspirin Use in Patients with Hypertension: Contraindications and Precautions

Which hypertensive patients should not take aspirin?

① Those whose blood pressure has not decreased: Data shows that for hypertensive patients whose blood pressure has not returned to normal, taking 75mg of aspirin daily will not only fail to reduce the risk of heart disease and stroke, but may also cause bleeding.

② Hypertensive patients without cardiovascular risk factors: Based on comprehensive assessment, patients without cardiovascular risk factors should not use aspirin as a preventative medication for cardiovascular disease. Otherwise, they will not only fail to benefit from it, but may also increase the risk of bleeding.

③ Hypertensive patients with bleeding tendencies: Aspirin is contraindicated in patients with conditions such as gastric ulcers, gastrointestinal bleeding, other active bleeding, hemophilia, abnormal coagulation function, thrombocytopenia, or those who have had hemorrhagic encephalopathy or have recently undergone ophthalmic, visceral, or intracranial surgery. It may also be contraindicated in individuals with specific conditions that may cause skin rashes, angioedema, or asthma.

④ Hypertensive patients with impaired kidney function: Aspirin affects renal blood flow. Taking aspirin may lead to or worsen kidney damage and may also increase bleeding tendencies. Recent reports indicate that many female patients with hypertension also suffer from varying degrees of kidney damage. Therefore, women with high blood pressure and severe arteriosclerosis should generally not take aspirin long-term.

What precautions should female patients with hypertension take when using aspirin? Female patients with hypertension should be aware of the side effects of aspirin. Most women with hypertension have varying degrees of kidney damage, and aspirin affects renal blood flow, potentially causing or worsening kidney damage and even exacerbating bleeding. Therefore, women with blood pressure above 170/110 mmHg and severe arteriosclerosis should generally not take aspirin long-term. Women who have recently experienced cerebral hemorrhage caused by hypertension should also avoid aspirin to prevent triggering or worsening the hemorrhage. Due to women's physiological characteristics, their blood clotting function may be reduced during menstruation. Aspirin may prolong menstruation and increase menstrual flow; therefore, it is best for women to reduce the dosage appropriately during menstruation for safety. Female patients with hypertension should take aspirin under the guidance of a doctor and pay attention to the following:

① Blood pressure should be well controlled, generally maintained at 130/85 mmHg, without symptoms such as dizziness or headache;

② Before taking aspirin, the coagulation mechanism should be checked, including platelet count and prothrombin time; if the platelet count is low, coagulation function is abnormal, or liver or kidney function is poor, aspirin should not be taken;

③ During the course of treatment, closely observe for side effects. If bruising, bleeding from the mouth or nose, or black stools are observed, it may be due to aspirin, and medical attention should be sought immediately.

When is the best time of day to take aspirin? Studies have shown that the peak time for cardiovascular and cerebrovascular events is between 6 am and 12 pm, and it takes 3 to 4 hours for enteric-coated aspirin to reach peak blood concentration. Generally speaking, the effect is greatest when the blood concentration is highest. The ideal treatment is to have the peak blood concentration before the peak time for cardiovascular and cerebrovascular events. If aspirin is taken every morning, its maximum therapeutic effect lasts until at least noon, thus failing to provide optimal protection. The period from 6 PM to midnight is the peak time for platelet production in the body. Taking aspirin at night ensures that its peak blood concentration occurs just before the peak period for cardiovascular events, maximizing its platelet-inhibiting effect. Studies have also found that for patients with mild hypertension, taking aspirin before bed has a mild blood pressure-lowering effect, while taking it in the morning has no such effect. Therefore, taking aspirin at night is most suitable. For patients who cannot take medication at night for various reasons, taking it in the morning is also acceptable. Because aspirin's inhibitory effect on platelets is irreversible, taking it regularly every day, only inhibiting the production of new platelets, is sufficient to provide protection.