The pharmacokinetics of losartan in renal insufficiency.

AIM: To determine the effect of renal insufficiency on the pharmacokinetics and pharmacodynamics of losartan (MK-954) and its metabolite E3174. PATIENTS AND METHODS: A two-center, unblinded trial was performed in 18 patients (age range 31-63 years) with various degrees of renal function grouped according to the renal clearance of creatinine: group I, creatinine clearance > or = 75 ml/min; group II, creatinine clearance 30-74 ml/min; group III, creatinine clearance 10-29 ml/min (n = 6 in all groups). Losartan (100 mg/day) was administered under supervised conditions for seven consecutive days. Plasma samples were taken for up to 60 h and 24-h urine collections were made following the final dose of losartan (on day 7) to determine losartan and E3174 concentrations, with simultaneous measurements of blood pressure and the pulse rate. RESULTS: The pharmacokinetic parameters for losartan and E3174 changed inconsequentially across the range of renal insufficiency. For losartan, renal clearance decreased from 50 +/- 19 ml/min in group I to 2.3 +/- 0.9 ml/min in group III (P < 0.05). For E3174, although the renal clearance decreased from 16 +/- 4.1 ml/min in group I to 1.3 +/- 0.8 ml/min in group III (P < 0.05), the area under the plasma concentration curve did not change. CONCLUSIONS: The steady-state areas under the curve of losartan and E3174 are not significantly changed with renal impairment. The renal clearance of losartan decreases with renal impairment but since only a small percentage of the dose is ordinarily eliminated by the kidney, the demonstrated reduction in clearance is clinically irrelevant. The renal clearance of E3174 also decreases with renal impairment, but the steady-state area under the curve does not increase with increasing degrees of renal insufficiency. These pharmacokinetic alterations do not warrant dose adjustment in the face of renal insufficiency.

Extended-release felodipine in patients with mild to moderate hypertension. Felodipine ER Dose-Response Study Group.

Two hundred eighty-six patients with mild to moderate hypertension who had untreated diastolic blood pressure while seated of 95 to 115 mm Hg were randomized to receive placebo or once-daily doses of 2.5, 5, or 10 mg of the dihydropyridine calcium channel blocker felodipine extended release (ER). Blood pressure was measured 24 hours after dosing (at trough). Mean reductions in diastolic blood pressure after 8 weeks of double-blind treatment were significantly greater in each of the ER felodipine treatment groups (2.5, 5, and 10 mg ER felodipine: -7.8, -9.5, and -11.3 mm Hg, respectively) than in the placebo group (-5.3 mm Hg). The effect was dose dependent for both diastolic and systolic blood pressure. Moreover, much of the peak antihypertensive effect was still present at trough, confirming the 24-hour efficacy of the drug. Felodipine was well tolerated.