Olmesartan is a widely used medication prescribed to manage high blood pressure, a condition also known as hypertension. Patients often encounter two similar-sounding names for this medication: olmesartan and olmesartan medoxomil. This dual terminology can lead to confusion regarding whether they refer to the same substance or different forms of the drug. This article aims to clarify the relationship between these two terms, explaining why both appear in medical contexts.
Olmesartan Medoxomil as the Prodrug
Olmesartan medoxomil is formally categorized as a prodrug, which means it is administered in an inactive form that the body must convert into an active drug. This chemical modification is not arbitrary; it serves a particular purpose in drug delivery. The design of olmesartan medoxomil specifically aims to improve how well the medication is absorbed from the digestive system into the bloodstream, a property known as bioavailability. The active form, olmesartan, has poor permeability on its own, so the medoxomil ester attachment enhances its passage through the intestinal wall, increasing its overall absorption to approximately 26% after oral administration.
How the Body Creates the Active Drug
After ingesting an olmesartan medoxomil tablet, the body activates it through a metabolic process. Enzymes in the wall of the intestine and within the liver rapidly break down the prodrug. This reaction, known as ester hydrolysis, or de-esterification, cleaves off the “medoxomil” portion of the molecule. This conversion happens quickly during the absorption phase. By the time the substance enters the general circulation, virtually all of the olmesartan medoxomil has been transformed into its active form, olmesartan.
The Function of Active Olmesartan
The resulting active drug, olmesartan, functions as an angiotensin II receptor blocker (ARB). This class of medications works by blocking the action of a natural hormone called angiotensin II. Angiotensin II causes blood vessels to constrict, which raises blood pressure. It also stimulates the release of aldosterone, a hormone that promotes the retention of sodium and water, contributing to higher blood pressure.
By blocking the binding of angiotensin II to its AT1 receptors, olmesartan helps blood vessels relax and widen, allowing blood to flow more freely and thus lowering blood pressure. This action also reduces aldosterone secretion, which helps decrease the body’s retention of sodium and water.
Why Both Names Appear on Your Prescription
The appearance of both “olmesartan” and “olmesartan medoxomil” on prescriptions or labels stems from pharmaceutical and medical conventions. “Olmesartan medoxomil” is the precise chemical name for the compound in the pill you swallow. This nomenclature is used in official drug information and regulatory documents because it accurately describes the administered form.
Conversely, “olmesartan” is often used as a convenient shorthand because it represents the active therapeutic agent that performs the blood pressure-lowering action within the body. For practical treatment purposes, these terms refer to the same medication. Whether the label specifies olmesartan or olmesartan medoxomil, you are receiving the drug designed to deliver the active olmesartan to your system.