Product Overview
[Drug Name]
Generic Name: Losartan Potassium Tablets
Trade Name: Primetsar
English Name: Losartan Potassium Tablets
Chinese Pinyin: Losartan Potassium Tablets
[Ingredients]
The main ingredient of this product is losartan potassium.
[Properties]
This product is a tablet.
[Indications]
This product is indicated for the treatment of essential hypertension.
[Dosage and Administration]
1. This product can be used in conjunction with other antihypertensive medications. 2. This product can be taken with or without food. 3. For most patients, the usual starting and maintenance dose is 50 mg once daily. Maximum antihypertensive effect is achieved after 3 to 6 weeks of treatment. In some patients, increasing the dose to 100 mg once daily may produce further antihypertensive effects. 4. For patients with vascular volume depletion (e.g., those receiving high-dose diuretics), a starting dose of 25 mg once daily may be considered. 5. For elderly patients or patients with renal impairment, including those on dialysis, no initial dose adjustment is necessary. A lower dose should be considered for patients with a history of hepatic impairment.
[Adverse Reactions]
Other adverse reactions reported post-marketing include: 1. Allergic reactions: Angioedema (including swelling of the larynx and glottis leading to airway obstruction, and/or swelling of the face, lips, pharynx, and/or tongue) has been reported in a very small number of patients treated with losartan. Some of these patients have previously experienced angioedema with other medications, including ACE inhibitors. Vasculitis, including Henoch-Schönlein purpura, has been reported rarely. 2. Gastrointestinal reactions: Hepatitis (rare reports), abnormal liver function, and vomiting. 3. General disorders and administration site conditions: Discomfort. 4. Hematologic: Anemia, thrombocytopenia (rare reports). 5. Musculoskeletal: Myalgia, arthralgia. 6. Neurological/psychiatric: Migraine, grand mal seizures, dysgeusia. 7. Reproductive disorders: Erectile dysfunction/impotence. 8. Respiratory: Cough. 9. Skin: Urticaria, pruritus, erythroderma. Photosensitivity. 10. Hyperkalemia and hyponatremia have been reported.
[Contraindications]
This product is contraindicated in patients with allergies to any component.
[Precautions]
1. Allergic Reactions: Angioedema. 2. Hypotension and Electrolyte/Fluid Imbalance: Patients with volume depletion (e.g., those receiving high-dose diuretics) may experience symptomatic hypotension. These conditions should be corrected before treatment with this product, or a lower initial dose should be used. It should be noted that electrolyte imbalances are common in patients with renal insufficiency, with or without diabetes. In clinical studies in patients with type 2 diabetes and proteinuria, the incidence of hyperkalemia was higher in the losartan potassium group compared with the placebo group; however, few patients discontinued treatment due to hyperkalemia. 3. Hepatic Impairment: Pharmacokinetic data indicate that plasma concentrations of losartan are significantly increased in patients with cirrhosis. Therefore, a lower dose should be considered in patients with a history of hepatic impairment. 4. Renal Impairment: Due to inhibition of the renin-angiotensin system, changes in renal function, including renal failure, have been reported in susceptible individuals; these changes resolve after discontinuation of treatment. In patients whose renal function depends on the activity of the renin-angiotensin-aldosterone system (e.g., patients with severe congestive heart failure), treatment with angiotensin-converting enzyme inhibitors can cause oliguria and/or progressive azotemia and (rarely) acute renal failure and/or death. Similar reports have also been reported with losartan. In patients with bilateral renal artery stenosis or unilateral renal artery stenosis, other drugs that affect the renin-angiotensin system can increase blood urea and serum creatinine levels. Similar reports have also been reported with this product. These changes in renal function resolve after discontinuation of treatment. Please read the package insert carefully and use as directed by your doctor.
[Use in Special Populations]
Precautions for Use in Children:
The safety and efficacy of this drug in children have not been established. Precautions During Pregnancy and Lactation:
Drugs that directly act on the renin-angiotensin system can cause harm or even death to the developing fetus when used during the second and third trimesters. This drug should be discontinued as soon as pregnancy is discovered. Although there is no experience with the use of this drug in pregnant women, animal studies with losartan potassium have demonstrated fetal and neonatal injury and death, the mechanism of which is believed to be drug-mediated effects on the renin-angiotensin system. Renal perfusion in the human fetus from the second trimester onward is dependent on the development of the renin-angiotensin system. Therefore, the risk to the fetus is increased if this drug is used during the second and third trimesters. It is unknown whether losartan is excreted in human milk. Because many drugs are excreted in human milk and can have adverse effects on nursing infants, the decision to discontinue nursing or discontinue the drug should be based on maternal considerations.
Precautions for the Elderly:
In clinical studies, there were no age-related differences in the efficacy and safety of this drug.
[Drug Interactions]
Clinical pharmacokinetic studies have confirmed no clinically significant drug interactions with hydrochlorothiazide, digoxin, warfarin, cimetidine, phenobarbital, ketoconazole, and erythromycin. Rifampicin and fluconazole have been reported to reduce levels of the active metabolite. The clinical consequences of these interactions have not been evaluated. 1. Like other drugs that inhibit angiotensin I1 and its effects, coadministration of this product with potassium-sparing diuretics (e.g., spironolactone, triamterene, amiloride), potassium supplements, or potassium-containing salt substitutes may result in elevated serum potassium. 2. Like other drugs that affect sodium excretion, lithium excretion may be reduced. Therefore, if lithium salts are coadministered with angiotensin I1 receptor antagonists, serum lithium levels should be carefully monitored. 3. Nonsteroidal anti-inflammatory drugs (NSAIDs), including selective cyclooxygenase-2 inhibitors (COX-2 inhibitors), may reduce the effects of diuretics and other antihypertensive drugs. Therefore, the antihypertensive effects of angiotensin II receptor antagonists or angiotensin-converting enzyme inhibitors may be attenuated by NSAIDs, including COX-2 inhibitors. 4. In some patients with impaired renal function (e.g., elderly or volume-depleted patients, including those receiving diuretics) who are taking nonsteroidal anti-inflammatory drugs, including selective COX-2 inhibitors, concomitant use of angiotensin receptor antagonists or angiotensin-converting enzyme inhibitors may result in further renal impairment, including the potential for acute renal failure. These effects are generally reversible. Therefore, caution should be exercised when administering these drugs together in patients with renal impairment.
[Pharmacological Action]
1. Mechanism of Action: Angiotensin II is the primary active substance in the renin-angiotensin system and a potent vasoconstrictor, playing a major role in the pathophysiology of hypertension. Angiotensin II binds to AT1 receptors in various tissues (such as vascular smooth muscle, adrenal glands, kidneys, and heart), producing a variety of important biological effects, including vasoconstriction and aldosterone release. It also stimulates smooth muscle cell proliferation. Another angiotensin II receptor subtype, AT2, has been identified, but its role in cardiovascular homeostasis remains unclear. Losartan is a synthetic, potent, orally active drug. Binding studies and pharmacological bioassays have demonstrated its selective binding to AT1 receptors. In vitro and in vivo studies have demonstrated that losartan and its pharmacologically active carboxylic acid metabolite (E-3174) can block the corresponding physiological effects of angiotensin II synthesized from any source or pathway. Compared to other peptide angiotensin II antagonists, losartan lacks agonist effects. Losartan selectively targets the AT1 receptor, without affecting the function of other hormone receptors or important ion channels in the cardiovascular system. It also does not inhibit angiotensin-converting enzyme (kininase II), which degrades bradykinin. Therefore, effects not directly related to AT1 receptor blockade, such as bradykinin-mediated effects or edema (losartan 1.7% vs. placebo 1.9%), are not related to losartan. 2. Toxicology Studies: The LD50 of losartan potassium in male mice following oral administration was 2248 mg/kg (6744 mg/m2) (1124 times the recommended maximum daily dose for adults). The minimum lethal doses (LDs) for oral administration of this drug in mice and rats were 1000 mg/kg (3000 mg/m2) and 2000 mg/kg (11800 mg/m2), respectively, which are 500 times and 1000 times the recommended maximum daily dose for an adult (based on a 50 kg body weight). The potential toxicity of losartan potassium was evaluated in a series of toxicity studies involving multiple oral administrations for three months in monkeys and one year in rats and dogs. No findings were found that would preclude its use at therapeutic doses. No carcinogenic effects were observed in rats and mice at the maximum tolerated dose for 105 and 92 weeks, respectively. In vitro alkaline elution and chromosomal aberration studies demonstrated no direct mutagenic effects at plasma concentrations 1700 times the maximum achievable human dose. Daily oral administration of losartan potassium to male and female rats at 150 and 300 mg/kg, respectively, did not affect reproductive performance. Losartan potassium can cause adverse reactions in rat embryos and neonates, including weight loss, mortality, and/or nephrotoxicity. Furthermore, elevated concentrations of losartan potassium and its active metabolites were observed in the milk of treated rats.
Storage: Store in a cool, dry place. Strength: 50mg
Packaging: 50mg x 7s/box
Validity: 24 months
Approval Number: National Medicine Standard H20110040
Manufacturer: Chongqing Kerui Pharmaceutical (Group) Co., Ltd.
