Anastrozole (often sold under the brand name Arimidex) is a medication used to treat hormone-receptor-positive breast cancer in postmenopausal women. This cancer is fueled by estrogen, and the drug works by lowering the body’s estrogen levels to slow or stop tumor growth. Anastrozole is an aromatase inhibitor, and its effectiveness in reducing cancer recurrence has made it a standard, long-term therapy. Understanding potential side effects, particularly concerning cardiovascular health, is important. This article explores the link between anastrozole use and the development of high blood pressure, known medically as hypertension.
Anastrozole and Hypertension: The Direct Link
Clinical evidence shows a clear association between anastrozole use and an elevated risk of developing high blood pressure. This adverse effect is frequently observed during treatment, often resulting in a new diagnosis of hypertension or worsening pre-existing high blood pressure. Major clinical trials, such as the Arimidex, Tamoxifen Alone or in Combination (ATAC) trial, have highlighted this cardiovascular risk compared to other hormone therapies like tamoxifen. Large-scale studies confirm that anastrozole raises the odds of developing hypertension. Therefore, regular blood pressure assessment is a necessary part of the long-term monitoring plan for patients undergoing this therapy.
How Anastrozole Affects Blood Pressure
The mechanism linking anastrozole to elevated blood pressure relates directly to its therapeutic purpose: the suppression of estrogen. Anastrozole blocks the aromatase enzyme, which converts androgens into estrogen in postmenopausal women. The resulting lack of estrogen removes a protective benefit this hormone typically provides to the cardiovascular system.
Estrogen helps maintain the flexibility of blood vessels by promoting vasodilation, or the widening of the vessels. Vasodilation is achieved through the production of nitric oxide, which signals smooth muscles in the vessel walls to relax. When anastrozole lowers estrogen, this protective vasodilation is diminished, leading to increased stiffness and narrowing of the arteries. This reduced flexibility forces the heart to pump harder, resulting in elevated blood pressure. Estrogen also regulates the kidneys, and its absence may interfere with the body’s ability to manage salt and fluid balance, further contributing to hypertension.
Monitoring and Managing Blood Pressure While Taking Anastrozole
Given the risk, monitoring blood pressure is a requirement for individuals taking anastrozole. Patients should check their blood pressure at home regularly using a validated device and keep a log of readings for their healthcare team. Any significant or sustained elevation should be promptly reported to the prescribing oncologist or primary care provider.
Lifestyle modifications can support healthy blood pressure and reduce the need for additional medication. Adopting a diet rich in fruits, vegetables, and whole grains, such as the DASH (Dietary Approaches to Stop Hypertension) diet, is recommended. Reducing sodium intake is beneficial because it impacts fluid retention and blood volume. Consistent physical activity, such as brisk walking or moderate aerobic exercise, also helps keep blood vessels flexible and maintain a healthy weight.
If blood pressure remains elevated despite these measures, medical intervention is necessary. The oncologist may collaborate with a cardiologist or primary care physician to initiate or adjust antihypertensive medications. Controlling blood pressure allows the patient to continue cancer treatment safely without increasing the risk of serious cardiovascular events.
Broader Cardiovascular Considerations
While hypertension is a notable side effect, anastrozole therapy is also associated with other changes affecting overall heart health. The drug can negatively alter the body’s lipid profile, increasing total cholesterol and low-density lipoprotein (LDL), sometimes called “bad” cholesterol. These changes are risk factors for the buildup of plaque in the arteries, a condition known as atherosclerosis.
Beyond lipid changes, there is potential for more serious cardiovascular issues. Studies suggest a higher risk of ischemic events, such as heart attack or stroke, compared to the use of tamoxifen. Anastrozole has also been linked to an increased risk of developing heart failure. Patients must discuss their personal cardiovascular history with their doctor to ensure appropriate monitoring and management of all related heart risks during treatment.