Losartan Potassium and Hydrochlorothiazide Tablets (Hyzaar) is a fixed-dose combination of losartan (an angiotensin II receptor blocker, ARB) and hydrochlorothiazide (a diuretic). It is widely used in the treatment of hypertension and patients with left ventricular hypertrophy. Rational drug use requires strict adherence to its precautions and monitoring requirements to balance efficacy and safety.
Precautions for Administration of Losartan Potassium and Hydrochlorothiazide Tablets (Hyzaar)
Contraindicated Populations
Pregnant women: This drug can cause fetal injury or even death, especially during the second and third trimesters of pregnancy. The drug must be discontinued immediately if pregnancy is detected.
Patients with hypersensitivity: Contraindicated in patients allergic to losartan, hydrochlorothiazide, or any of the excipients.
Patients with severe renal impairment (anuria): May exacerbate the deterioration of renal function.
Diabetic patients receiving aliskiren: Concomitant use increases the risk of hyperkalemia and renal damage.
Adjustments for Special Populations
Patients with hepatic impairment: Initial treatment with this combination tablet is not recommended, as there is no 25 mg losartan initial dosage form available.
Elderly patients: Dose adjustment should be performed with caution, 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: More 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 medication.
Electrolyte imbalance: Hydrochlorothiazide may cause hypokalemia, hyponatremia, and hypomagnesemia, while losartan may induce 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 intervention measures taken.
Drug Interactions
Nonsteroidal anti-inflammatory drugs (NSAIDs, e.g., ibuprofen): May reduce the antihypertensive effect and increase the risk of renal injury.
Lithium preparations: Hydrochlorothiazide increases serum lithium concentration, which may lead to lithium toxicity.
Antidiabetic drugs: Dose adjustment is required, as hydrochlorothiazide may interfere with blood glucose control.
Monitoring for Losartan Potassium and Hydrochlorothiazide Tablets (Hyzaar) Administration
Efficacy Monitoring
Blood pressure control: Efficacy should be evaluated 3 weeks after the initiation of treatment, and the dose adjusted according to blood pressure (e.g., increased from 50/12.5 mg to 100/25 mg).
Patients with left ventricular hypertrophy: Focus on monitoring stroke risk indicators and blood pressure target achievement.
Safety Monitoring
Renal function: Serum creatinine should be tested before medication and regularly during treatment, especially in high-risk patients (e.g., those with renal artery stenosis).
Electrolytes: Baseline and regular testing of serum potassium, sodium, and magnesium levels is required to prevent imbalances.
Uric acid and blood glucose: Hydrochlorothiazide may increase uric acid and blood glucose levels; signs of gout exacerbation or worsening diabetes should be closely monitored.
