Losartan Potassium and Hydrochlorothiazide Tablets (Hyzaar) is a fixed-dose combination preparation containing losartan (an angiotensin II receptor blocker, ARB) and hydrochlorothiazide (a diuretic). It is widely used in the treatment of hypertension and patients with hypertension complicated by left ventricular hypertrophy. For rational drug use, it is essential to strictly follow its precautions and monitoring requirements to balance efficacy and safety.

Precautions for Using Losartan Potassium and Hydrochlorothiazide Tablets (Hyzaar)

Contraindicated Populations

Pregnant women: This drug may cause fetal injury or even death, especially during the second and third trimesters of pregnancy. The drug must be discontinued immediately once pregnancy is confirmed.

Patients with allergies: Contraindicated in patients allergic to losartan, hydrochlorothiazide, or any excipients of the drug.

Patients with severe renal impairment (anuria): May exacerbate the deterioration of renal function.

Diabetic patients using aliskiren concurrently: Concurrent use increases the risk of hyperkalemia and renal damage.

Dosage Adjustments for Special Populations

Patients with hepatic impairment: Initial treatment with this drug is not recommended, as there is no available dosage form with a starting dose of 25mg losartan.

Elderly patients: Dosage adjustment must be done cautiously, especially when combined with renal function decline.

Black patients: The benefit of reducing stroke risk associated with left ventricular hypertrophy may not be applicable.

Potential Risks and Countermeasures

Hypotension: Likely to occur in patients with volume depletion or salt depletion (e.g., those using high-dose diuretics). Blood volume must be corrected before initiating the drug.

Electrolyte imbalance: Hydrochlorothiazide may cause hypokalemia, hyponatremia, and hypomagnesemia, while losartan may lead to hyperkalemia. Regular monitoring of electrolytes is required.

Acute kidney injury: Patients with renal artery stenosis, heart failure, or dehydration are at higher risk; renal function monitoring is necessary.

Allergic reactions: Such as angioedema and rash. The drug must be discontinued immediately and appropriate interventions initiated.

Drug Interactions

NSAIDs (e.g., ibuprofen): May reduce the antihypertensive effect and increase the risk of renal damage.

Lithium preparations: Hydrochlorothiazide increases serum lithium concentration, which may cause lithium toxicity.

Antidiabetic drugs: Dosage adjustment is required, as hydrochlorothiazide may interfere with blood glucose control.

Medication Monitoring for Losartan Potassium and Hydrochlorothiazide Tablets (Hyzaar)

Efficacy Monitoring

Blood pressure control: Evaluate the therapeutic effect 3 weeks after initiating treatment, and adjust the dosage according to blood pressure (e.g., increase from 50/12.5mg to 100/25mg).

Patients with left ventricular hypertrophy: Focus on monitoring stroke risk indicators and blood pressure target achievement.

Safety Monitoring

Renal function: Measure serum creatinine before initiating the drug and regularly during treatment, especially in high-risk patients (e.g., those with renal artery stenosis).

Electrolytes: Conduct baseline and regular checks of serum potassium, sodium, and magnesium to prevent imbalances.

Uric acid and blood glucose: Hydrochlorothiazide may increase uric acid and blood glucose levels; attention should be paid to signs of gout exacerbation or worsening diabetes.