How long does losartan last
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Duration of Losartan's Effects: Pharmacokinetics and Efficacy
Pharmacokinetics of Losartan and Its Metabolite E-3174
Losartan, an angiotensin II receptor antagonist, is rapidly absorbed after oral administration, reaching peak plasma concentrations within 1 to 2 hours . The drug undergoes extensive first-pass metabolism, with approximately 14% of the dose converted to its active metabolite, E-3174, which is significantly more potent than losartan itself . The terminal half-life of losartan ranges from 1.5 to 2.5 hours, while E-3174 has a longer half-life of 6 to 9 hours, contributing to the drug's prolonged effects 12.
Duration of Antihypertensive Effects
The antihypertensive effects of losartan are primarily due to its active metabolite, E-3174, which maintains higher plasma concentrations and a longer half-life compared to losartan 12. Studies have shown that the pharmacokinetics of losartan and E-3174 remain consistent with repeated dosing, indicating stable drug levels over time 12.
Extended-Release Formulations
To enhance the duration of losartan's antihypertensive effects, extended-release formulations have been developed. For instance, Losartan Cronos, a bilayer tablet containing both immediate and extended-release components, has been shown to provide effective blood pressure control over a 24-hour period . This formulation ensures a sustained release of the drug, maintaining therapeutic levels throughout the day and improving patient adherence .
Clinical Efficacy and Safety
Clinical trials have demonstrated that losartan, administered once daily, effectively reduces blood pressure and provides end-organ protection in various conditions such as diabetic nephropathy, heart failure, and post-myocardial infarction 256. The drug is well-tolerated, with a safety profile comparable to placebo, and does not require dosage adjustments for age, sex, or mild hepatic impairment 25.
Conclusion
Losartan's antihypertensive effects are primarily driven by its active metabolite, E-3174, which has a longer half-life and higher potency. While the immediate-release form of losartan may require twice-daily dosing for some patients, extended-release formulations like Losartan Cronos can provide effective 24-hour blood pressure control. Overall, losartan is a safe and effective option for managing hypertension and related conditions.
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