How long does losartan take to work
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How Long Does Losartan Take to Work?
Pharmacokinetics of Losartan: Absorption and Metabolism
Losartan, an angiotensin-receptor antagonist, is rapidly absorbed after oral administration. It reaches its maximum concentration in the bloodstream within 1 to 2 hours post-administration. This quick absorption is crucial for its effectiveness in managing hypertension and other cardiovascular conditions.
Conversion to Active Metabolite E 3174
Approximately 14% of a losartan dose is converted to its active metabolite, E 3174, which is significantly more potent than losartan itself. E 3174 has a terminal half-life ranging from 6 to 9 hours, contributing to the drug's overall efficacy. This conversion process ensures that losartan remains effective over a longer period, even with a single daily dose.
Initial Effects and Blood Pressure Reduction
Patients typically start to see a reduction in blood pressure within a few hours of taking losartan. The initial dose of 50 mg/day is effective and can be administered without regard to food. For those who do not achieve the desired blood pressure reduction, the dose can be increased to 100 mg/day, either as a single dose or split into two doses.
Long-Term Efficacy and Combination Therapies
In a study comparing the efficacy of losartan combined with amlodipine versus losartan combined with hydrochlorothiazide, patients were initially given losartan 50 mg monotherapy for 4 weeks. This was followed by an additional 20 weeks of combination therapy. The study found that losartan, particularly when combined with amlodipine, showed dominant efficacy in reducing 24-hour mean brachial and central blood pressure. This indicates that while losartan starts working within hours, its full benefits in blood pressure management are more pronounced over a longer period, especially when used in combination therapies.
Conclusion
Losartan begins to work within 1 to 2 hours of oral administration, with its active metabolite E 3174 contributing to its prolonged efficacy. Initial blood pressure reduction can be observed within a few hours, but optimal results, especially in combination therapies, are typically seen over several weeks. This makes losartan a reliable option for long-term management of hypertension and related cardiovascular conditions.
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