Peak Time of Irbesartan After Oral Administration
Irbesartan reaches peak plasma concentrations at 1.5 to 2 hours after oral administration. 1
Pharmacokinetic Profile
- Peak plasma levels (Tmax) occur at 1.5 to 2 hours following oral dosing in both healthy subjects and hypertensive patients 1, 2
- The oral absorption is rapid and complete, with an average absolute bioavailability of 60% to 80% 1
- Food does not affect the bioavailability or peak timing of irbesartan 1, 2
Peak Pharmacodynamic Effect vs. Peak Concentration
- While peak plasma concentration occurs at 1.5 hours, the maximal blood pressure reduction occurs later, between 3 and 6 hours after dosing 2, 3
- This temporal dissociation creates a clockwise hysteresis pattern, where peak antihypertensive effect lags behind peak drug concentration by approximately 2.5 hours 3
- Complete inhibition (100%) of the pressor effect of angiotensin II occurs at 4 hours following oral doses of 150 mg or 300 mg 1
Clinical Implications
- The rapid absorption with peak at 1.5-2 hours, combined with a terminal elimination half-life of 11 to 15 hours, allows for effective 24-hour blood pressure control with once-daily dosing 1, 2
- Steady-state concentrations are achieved within 3 days of repeated once-daily dosing 1
- Limited accumulation (<20%) occurs with repeated dosing and is not clinically relevant 1