Generic

Losartan Potassium + Hydrochlorothiazide

Indications

is suitable for the treatment of hypertension. It has also been shown to reduce the risk of stroke in patients with hypertension and left ventricular hypertrophy.

Pharmacology

Angiotensin II is formed by angiotensin I in the reaction catalyzed by angiotensin converting enzyme (ACE). It is an effective vasoconstrictor and the main vasoactive hormone of the renin-angiotensin system. An important part of the pathophysiology of hypertension. It also stimulates the adrenal cortex to secrete aldosterone. Losartan and its main active metabolite block the vasoconstriction and aldosterone secretion of angiotensin II by selectively blocking the binding of angiotensin II to AT1 receptors found in many tissues (such as vascular smooth muscle, adrenal glands). In vitro binding studies have shown that Losartan is a competitive and reversible AT1 receptor inhibitor. Neither losartan nor its active metabolite inhibit ACE (kinase II, an enzyme that converts angiotensin I to angiotensin II and breaks down bradykinin); they also do not bind to or block known important cardiovascular regulation at other hormone receptors or ion channels It is known to be important for cardiovascular regulation.

Hydrochlorothiazide is a thiazide diuretic. Thiazides affect the mechanism of renal tubular electrolyte reabsorption and directly increase the excretion of approximately the same amount of sodium and chlorine. Indirectly, the diuretic effect of hydrochlorothiazide reduces plasma volume, leading to increased plasma renin activity, increased aldosterone secretion, increased urinary potassium loss, and decreased serum potassium. Renal aldosterone binding is mediated by angiotensin II, so co-administration of angiotensin II receptor antagonists tends to reverse the potassium loss associated with these diuretics.

Dosage

 Hypertension 

The usual starting dose of 50 / 12.5 is a once-a-day tablet.
For patients who do not respond well to tablets, the dose can be increased to 100/25 once a day.
Patients who cannot adequately control blood pressure by taking losartan 100 mg alone can switch to this combination, 100/12.5 once a day.
For hypertensive patients with left ventricular hypertrophy, the starting dose is 50/12.5. If the blood pressure needs to be further lowered, 100/12.5 can be given, and 100/25 if necessary. The maximum dose is 100/25 once a day.
Generally speaking, the blood pressure reduction effect can be achieved within three weeks after starting treatment.
elderly patients do not need to adjust the 50/12.5 starting dose. However, the maximum dose of 100/25 once a day should not be used as the initial treatment for elderly patients.

Severe hypertension

The initial dose of for the initial treatment of severe hypertension is 50/12.5 tablets once a day.
For patients who do not fully respond to the dose after 2 to 4 weeks of treatment, the dose can be increased to 100/25 once a day. The maximum dose is 100/25 tablets once a day.

Administration

The preparation can be administered together with other antihypertensive drugs. It can be administered with or without food.

Interaction

Losartan potassium:

No significant pharmacokinetic interactions were found in interaction studies with hydrochlorothiazide, digoxin, warfarin, cimetidine, and phenobarbital. Like other medicines that block angiotensin II or its effects, the simultaneous use of potassium-sparing diuretics (such as spironolactone, triamterene, amiloride), potassium supplements or potassium-containing salt substitutes may cause an increase in serum potassium. Like other antihypertensive drugs, the antihypertensive effect of losartan can be weakened by the non-steroidal anti-inflammatory drug indomethacin.
Hydrochlorothiazide:

When administered at the same time, the following medications may interact with thiazide diuretics: Alcohol, barbiturates, or anesthetics can cause orthostatic hypotension.
Hypoglycemic medications (oral medications and insulin): The dose of hypoglycemic medications may need to be adjusted.

Other antihypertensive drugs: have additive or synergistic effects.

Cholestyramine and colestipol resin: In the presence of anion exchange resin, the absorption of hydrochlorothiazide is impaired.

Contraindications

Patients allergic to any component of this product should not use the combination of losartan and hydrochlorothiazide. Because it contains hydrochlorothiazide, patients with anuria or allergic to other sulfonamides should not use this product.

Side Effects

Side effects are usually mild. Symptomatic hypotension, including dizziness, may occur, especially in patients with insufficient intravascular volume (eg, patients taking high-dose diuretics). Hyperkalemia occasionally occurs; some angiotensin II receptor antagonists have also reported angioedema. Dizziness; less common gastrointestinal disorders, angina, palpitations, edema, dyspnea, headache, sleep disturbances, malaise, hives, itching, rash; rarely hepatitis, atrial fibrillation, cerebrovascular accident, syncope, paraesthesia; Pancreatitis, allergic reactions, cough, depression, erectile dysfunction, anemia, thrombocytopenia, hyponatraemia, arthralgia, myalgia, kidney failure, rhabdomyolysis, tinnitus, photosensitivity, and vasculitis (including allergic purpura).

Pregnancy & Lactation

Unless necessary, angiotensin II receptor antagonists should be avoided during pregnancy. They can negatively affect blood pressure control and kidney function in fetuses and newborns; Skull defects and oligocephaly have also been reported. Information on the use of angiotensin II receptor antagonists in lactation is limited. They are not recommended for breastfeeding and there are alternative treatment options available, with better information on safety during breastfeeding.

Precautions & Warnings

Hypersensitivity: Angioedema  should be measured regularly for serum electrolytes, and possible electrolyte imbalances should be detected at appropriate intervals.  Hypokalemia may rarely occur, especially severe diuresis, severe liver cirrhosis, or impaired renal function after long-term treatment.Symptomatic hypotension

Therapeutic Class

Combined antihypertensive preparation

Storage Conditions

Do not store above 30°C. Please keep out of reach of children.

Pharmaceutical Name

Drug International Ltd.