This article is from "Nankai Sun Pharmacist", which is used for medical science popularization for reference. Irbesartan hydrochlorothiazide is a single compound antihypertensive drug, composed of irbesartan and hydrochlorothiazide two first-line antihypertensive drugs, irbesartan belongs to angiotensin II receptor antagonists, by selectively binding to the AT1 receptor of angiotensin II, so that angiotensin II dissociates from the binding site of the receptor, blocks the harmful effect of angiotensin II, thereby relaxing vascular smooth muscle, reducing the level of aldosterone in the blood, promoting the excretion of water and sodium, and exerting a hypotensive effect, its antihypertensive effect is slow, but stable and long-lasting, and has the ability to protect cardiovascular, kidneys and improve glucose metabolism. Hydrochlorothiazide is a medium-acting diuretic, mainly through sodium excretion diuresis, reducing blood volume, dilating blood vessels, reducing peripheral vascular resistance, lowering blood pressure, antihypertensive effect is stable, slow, long-lasting, and can protect cardiovascular and cerebrovascular vessels.
Hydrochlorothiazide can inhibit potassium ion reabsorption, promote potassium excretion, easily cause hypokalemia, irbesartan dilates glomerular outflow arterioles stronger than dilating glomerular inductive arterioles, thereby causing a decrease in glomerular filtration rate, and can inhibit the release of aldosterone, increase blood potassium, thereby reversing the loss of potassium ions related to hydrochlorothiazide, in addition, hydrochlorothiazide can also inhibit insulin release, reduce glucose tolerance, increase blood glucose, and irbesartan can improve insulin resistance, improve insulin sensitivity, improve glucose metabolism, can antagonize the increase in blood sugar caused by hydrochlorothiazide, hydrochlorothiazide lowers blood pressure and activates the renin-angiotensin-aldosterone system, which has a negative effect on blood pressure, and irbesartan counteracts this adverse factor by inhibiting the overactivation of the renin-angiotensin-aldosterone system. Therefore, the combination of irbesartan and hydrochlorothiazide can exert a synergistic antihypertensive effect, protect target organs, and reduce the incidence of adverse reactions.
Irbesartan alone rarely causes hypotension, and the combination with hydrochlorothiazide can cause symptomatic hypotension, especially in the early stage of medication, because hydrochlorothiazide can cause a decrease in blood volume, and when combined with irbesartan, it is easy to induce hypotension, which is manifested as blackness in front of the eyes, dizziness, Dizziness and other symptoms, especially when suddenly changing body position, such as lying on the bed and suddenly getting up or squatting down and suddenly standing up, hypotension is more likely to occur, dizziness caused by irbesartan hydrochlorothiazide is related to orthostatic hypotension, it is recommended to start with a small dose (1 tablet) at the initial stage of medication, blood pressure changes should be monitored at the beginning of medication, to avoid sudden change of position, once hypotension occurs, lie down immediately, generally 10-20 minutes can be relieved, if necessary, infusion of normal saline to correct hypotension.
In short, irbesartan hydrochlorothiazide is a commonly used single-tablet compound antihypertensive drug in clinical practice, and the combination of the two drugs can not only improve the antihypertensive efficacy, but also increase the protection of target organs and reduce adverse reactions. Erbesartan hydrochlorothiazide is prone to hypotension in the early stage of treatment, causing dizziness, should be vigilant to prevent falls, it is recommended to start with a small dose (1 tablet), monitor blood pressure changes, avoid sudden change of position, once hypotension occurs, immediately lie down, if necessary, infusion of normal saline to correct hypotension.