Olmesartan medoxomil is a widely used prescription medication primarily for managing high blood pressure, or hypertension. It is approved for use in adults and children aged six years and older. The drug helps reduce the long-term risk of serious cardiovascular events, such as stroke and heart attack, which result from uncontrolled blood pressure, by intervening in the body’s natural blood pressure regulation system.
Therapeutic Role and Classification
Olmesartan medoxomil treats essential hypertension (high blood pressure with no identifiable cause). It is often used alone or combined with other blood pressure-lowering medications, such as diuretics, to enhance the overall reduction effect.
The drug belongs to the class of Angiotensin II Receptor Blockers (ARBs). This classification reflects its mechanism of action within the renin-angiotensin-aldosterone system (RAAS), the body’s blood pressure control system. Available under the brand name Benicar, it is also widely available as a generic medication.
How Olmesartan Medoxomil Works
Olmesartan medoxomil is considered a prodrug, meaning it is inactive when swallowed and must be converted into its active form, olmesartan, within the gastrointestinal tract during absorption. This active metabolite then travels through the bloodstream to exert its therapeutic effect. The action of this medication is highly specific, targeting a key regulatory pathway in the body.
Olmesartan works by selectively blocking the angiotensin II type 1 (AT1) receptors found on the smooth muscle cells of blood vessels and other tissues. Olmesartan prevents the hormone Angiotensin II from binding to these AT1 receptors, acting as a selective antagonist. This blockade stops Angiotensin II from causing blood vessels to constrict and narrow.
The resulting effect is vasodilation (the widening of blood vessels), which directly reduces blood pressure. Blocking the AT1 receptors also inhibits aldosterone release from the adrenal glands. Since aldosterone signals the kidneys to retain sodium and water, reducing its levels helps decrease overall fluid volume and further lowers blood pressure.
Guidelines for Safe Administration
This medication is typically taken once daily to ensure consistent blood pressure control. For most adults, the usual starting dose is 20 milligrams once a day, with a maximum recommended dose of 40 milligrams daily. The drug can be taken with or without food, but establishing a routine of taking it at the same time each day helps maintain steady levels in the bloodstream.
Proper storage is necessary to preserve the medication’s effectiveness; it should be kept in a closed container at room temperature, away from excessive heat, moisture, and direct light. It is also important to avoid freezing the tablets. If a dose is missed, the general instruction is to take it as soon as it is remembered unless it is almost time for the next scheduled dose. In that case, the missed dose should be skipped entirely, and the patient should resume the regular schedule, never taking two doses at once to make up for a missed one.
Patients must continue taking the medication as directed, even if they feel better, since hypertension often has no noticeable symptoms. Stopping the drug abruptly without consultation is not advised, as this could lead to a sudden increase in blood pressure. Regular monitoring of blood pressure and kidney function is part of the ongoing treatment plan.
Important Safety Considerations
Olmesartan medoxomil carries a significant safety warning regarding pregnancy, classified as a Category D risk in the second and third trimesters. The medication can cause serious harm, injury, or death to the developing fetus by reducing fetal renal function and leading to conditions like oligohydramnios. Women who are pregnant or become pregnant while taking this drug must discontinue it immediately and consult their doctor.
Common side effects include dizziness, headache, and back pain. More serious, though less common, adverse effects include angioedema (swelling of the face, lips, or throat), which requires immediate medical attention. A notable long-term gastrointestinal issue is sprue-like enteropathy, characterized by severe diarrhea and weight loss.
The drug must be used with caution in patients who have severe kidney or liver impairment, as the body may not be able to process the medication efficiently. Olmesartan can also lead to hyperkalemia, which is an elevated level of potassium in the blood. The risk of hyperkalemia is higher when the drug is taken with potassium supplements or potassium-sparing diuretics. Nonsteroidal anti-inflammatory drugs (NSAIDs) can reduce the blood pressure-lowering effect of olmesartan and may increase the risk of kidney function decline. Additionally, combining olmesartan with the drug aliskiren is contraindicated for patients with diabetes.