Hyzaar (Losartan Potassium / Hydrochlorothiazide)

High blood pressure can be an alarming condition if it acquires a long-term character. In this case it's fraught with the development of #1 national diseases-killers - a heart attack and stroke. That's why if you tend to have high blood pressure, you may be recommended to resort to the medications which work is to relax the blood vessels, remove excesses of water and salt from blood and contribute to the prevention of the mentioned serious health conditions. One of such drugs is Hyzaar (losartan potassium / hydrochlorothiazide). Though not treating the high blood pressure directly, it has proved a good record in lowering hypertension, when applied in adults.

The brand-name Hyzaar is produced by Merck & Co. You may also opt to use generics forms of the medication. The drug contains two ingredients - Cozaar and hydrochlorothiazide.

Cozaar belongs to the group of angiotensin II receptor blockers (ARB). Angiotensin II is actually the culprit of the vessel constriction (vessel narrowing). Blocking Angiotensin II, Cozaar prevents this constriction, relaxing vessels.

Hydrochlorothiazide belongs to the group of diuretics, which promote the function of water and salt withdrawal from the blood by kidneys. When excesses of water and salt are removed from the blood, its volume decreases and blood vessels relax.

Attention! Hyzaar is forbidden for usage in pregnant women. If you are planning on becoming pregnant, stop taking the medication. If you become pregnant in the course of your therapy with Hyzaar, stop taking the drug and immediately contact your doctor. The medication can harm a fetus very seriously or even cause death of an unborn baby.


Hyzaar uses
Hyzaar uses
Hyzaar is recommended to treat high blood pressure in adults. The drug is not used in children.

What blood pressure results are considered high?

When blood pressure is measured, we obtain two parameters - the systolic blood pressure (the 1st, top number) and the diastolic blood pressure (the 2nd, bottom number). To define whether your blood pressure is high or not, you must do multiple blood pressure readings to confirm the result. If in this case the figures are higher than 140/90, you have high blood pressure.

What effect does Hyzaar bring?

Clinical studies of the medication proved that it lowers exponentially both systolic and diastolic blood pressure, besides the effectiveness grows with higher dosages of the medicine. Not being a panacea for high blood pressure, the drug achieves great results in lowering hypertension, thus reducing the risks of a heart attack or stroke.


Hyzaar dosage
Hyzaar dosage
What Is Hyzaar recommended dosage?
  • Hyzaar 50 mg/12.5 mg once a day
  • Hyzaar 100 mg/25 mg once a day

Which one of these 2 dosages will be recommended to you personally depends on your initial blood pressure response and whether the medication produces side effects on your organism or not. Taking into account these considerations, your healthcare provider may also increase or decrease your dosage of Hyzaar. The changes of dosages suggest quite a long-term usage (around a month) before you can fully evaluate the effect of lowering blood pressure in your case.

How to take Hyzaar?

Note that to obtain the maximum positive effect from the medication, you must take it strictly as prescribed by your healthcare provider. Otherwise, it will not work properly. Here are important general recommendations on how to take Hyzaar:
  • The medication is taken orally (by mouth) with a glass of plain water, with or without meals at the same time every day. That will provide the even concentration of the medication in your blood.
  • If you forget to take the current dose, you are supposed to take the next one as soon as you remember. In case it's already almost the time for your next dose, skip the missed one and continue taking the medication as prescribed. Don't take a double dose in this case.
  • Whenever you encounter any uncertainties as to how to use the medication, contact your healthcare provider or another medical professional for a consultation. Without professional advice don't stop your therapy with the medicine.

Warnings and Precautions

Hyzaar warnings
Hyzaar warnings
Before starting to use the medicine, inform your healthcare provider of any allergies you have. You may be allergic to any active or inactive ingredient in the drug's composition. In this case you mustn't use the product.

Let your healthcare provider know if you have a history of any serious conditions like kidney disease, liver disease, gout, lupus, severe dehydration or volume depletion, etc.

In diabetes patients the medication may influence blood sugar levels. That's why it's important to monitor the level of sugar in blood for such patients. In case of any complications, your healthcare provider will amend your diabetes therapy, adjusting dosages of diabetes medications.

In women of the child-bearing age, the Hyzaar therapy must be combined with the usage of reliable birth control pills, as the drug in case of pregnancy may cause fatal damage to an unborn baby. If you are planning on becoming pregnant or may become pregnant while taking Hyzaar, inform your doctor about that as soon as possible.

Breastfeeding women should discuss the possibility of the Hyzaar usage during the period of breastfeeding, as the ingredients of the medication pass through the breast milk to the nursing baby.

When taking Hyzaar, limit consumption of alcohol.

Be aware that the medication may impair your alertness. That's why if you are feeling dizzy, avoid driving, working with machinery, that can be dangerous or any other similar activity until you feel better.

The medication may cause such unpleasant side effects as increased sweating, vomiting or diarrhea, which, in their turn, may provoke sever dehydration and/or lightheadedness. To decrease the risks of dehydration drink enough water and inform your doctor of any serious side effects you are experiencing.

Your potassium levels may be affected while you are taking the medication. However, you shouldn't prescribe yourself any potassium supplements without coordinating this step with your healthcare provider.

If you are expecting any surgeries or dental procedures, let your doctor know that you are taking Hyzaar or/and any other medication, non-prescription or herbal supplements.

Hyzaar may increase your sensitivity to the sun. When taking the medication, try to avoid staying under the sun for a long time, use sunscreen protection and protective clothes if you plan to be exposed to the sun, especially in summer. Procedures with tanning booths or sunlamps should be restricted for the period of your therapy with the medication.

Older individuals, taking Hyzaar are more prone to the side effects of the medication, which most frequently include dizziness and kidney effects.

Side Effects

Allergic reactions:
  • Face, lips, tongue, or throat edema
  • Impaired breathing
  • Hives

Seek for the immediate medical attendance in case of the severe allergic reactions. Note that extremely rarely Hyzaar may cause the skeletal muscle tissue breakdown, leading to the renal failure. This condition belongs to the high-risk complications, accompanied by such symptoms as fever, weakness, unexplained muscle pain, unusual tiredness, along with dark colored urine. Contact your doctor immediately in case of these symptoms.

Hyzaar side effects
Hyzaar side effects
Serious side effects:
  • Pale or yellow skin/eyes, bruising or bleeding
  • Increased or slow heart rate and weak pulse
  • Muscle weakness, lightheartedness, fainting
  • Problems with the eyesight, pain in the eyes
  • Edema or unexplained weight gain
  • Increased thirst, loss of appetite
  • Severe nausea and vomiting
  • Frequent mood changes, drowsiness, confusion

Stop using the medication and let your doctor know if you have any of these serious side effects.

Moderate side effects:
The medication may also cause other side effects. If you are concerned about how the drug makes you feel, contact your physician for qualified medical advice.

Mechanism of action

Losartan formula
Losartan formula
The development of hypertension is closely connected with the work of the chemical angiotensin II.

Angiotensin II
  • It's a potent vasoconstrictor.
  • It's the major vasoactive hormone in the renin-angiotensin system.
  • It's a hormone that stimulates the aldosterone secretion by the adrenal cortex.
  • It binds to the AT1 receptor that is found in many body tissues (vascular smooth muscle, adrenal gland).

How does Hyzaar active components affect the mechanism of hypertnetion?

Hydrochlorothiazide formula
Hydrochlorothiazide formula
Losartan blocks Angiotensin II and its aldosterone-secreting effects by restricting its binding to the AT1 receptor (without exhibiting any partial agonist activity at the AT1 receptor).

Losartan, as well as its active metabolite, neither blocks nor binds any other important ion channels or hormone receptors, crucial for the cardiovascular regulation.

Hydrochlorothiazide increases directly sodium and chloride excretion, affecting the renal tubular mechanisms in the process of electrolyte reabsorption.

Hydrochlorothiazide indirect action is revealed through the reduction of the plasma volume, decrease of serum potassium and increases of the plasma renin activity, aldosterone secretion, and urinary potassium loss.


Dupont chemical
Dupont chemical
Today Hyzaar is a combination of 2 drugs - losartan potassium and hydrochlorothiazide, which historically were discovered and used independently.

Losartan potassium owns its origin to the chemists at Dupont - David J. Carini, Pancras C. Wong and John V. Duncia. Invented in 1990, the drug became a pharmaceutical bestseller in 2005, having earned $3 billion within just a year.

Hydrochlorothiazide, a diuretic medication that is the other major component of Hyzaar, has a longer history than losartan potassium yet its historical significance is by no means smaller. The diuretic, sold under the brand name Esidrix since 1958, has been one of the most frequently prescribed medications for the high blood pressure treatment. Hydrochlorothiazide was discovered by Dr. George de Stevens, who was in chief of the Charles A. Dana Research Institute, N.J.

Generic Hyzaar

The brand name medication is produced by the company Merck & Co. You may also find generic forms of the drug.
Generic Hyzaar
Generic Hyzaar

What are generic Hyzaar strengths?

  • Losartan-hydrochlorothiazide 50 mg/12.5 mg (losartan - 50 mg, hydrochlorothiazide - 12.5 mg)
  • Losartan-hydrochlorothiazide 100 mg/12.5 mg (losartan - 100 mg, hydrochlorothiazide - 12.5 mg)
  • Losartan-hydrochlorothiazide 100 mg/25 mg mg (losartan - 100 mg, hydrochlorothiazide - 25 mg)

Generic Losartan-hydrochlorothiazide is presently marketed by Teva Pharmaceuticals and a few other manufactures.

Generic Losartan-hydrochlorothiazide or brand name Hyzaar?

Many people wonder if they can use generics instead of brand-name medications. In this question it's important to look whether the generic you plan to use has been FDA approved or not. The U.S. Food and Drug Administration obliges all generics to undergo specific tests on correspondence to the brand-name drugs. Basing on these tests, indicting the equivalence of generics to brand name medications, FDA assigns a certain rating to the tested generic. "AB" is the highest rating FDA can assign.

All losartan-hydrochlorothiazide generics, approved by FDA, possess "AB rating", which means you can safely use them as equivalents of the brand-name Hyzaar, unless you have allergies to any inactive ingredients (fillers, dyes, etc.), available in a generic version and absent in Hyzaar. That's why it will not be superfluous to check with your healthcare provider the full list of the generic's active and inactive ingredients before you start using the medication.
Madnix . Wildsultan

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