Absorption
After oral administration, ezetimibe is absorbed and extensively conjugated to a pharmacologically active phenolic glucuronide (ezetimibe-glucuronide). After a single 10-mg dose of ezetimibe to fasted adults, mean ezetimibe peak plasma concentrations (Cmax) of 3.4 to 5.5 ng/mL were attained within 4 to 12 hours (Tmax). Ezetimibe-glucuronide mean Cmax values of 45 to 71 ng/mL were achieved between 1 and 2 hours (Tmax). There was no substantial deviation from dose proportionality between 5 and 20 mg. The absolute bioavailability of ezetimibe cannot be determined, as the compound is virtually insoluble in aqueous media suitable for injection.
Effect of Food on Oral Absorption
Concomitant food administration (high-fat or non-fat meals) had no effect on the extent of absorption of ezetimibe when administered as ezetimibe 10-mg tablets. The Cmax value of ezetimibe was increased by 38% with consumption of high-fat meals. Ezetimibe can be administered with or without food.
Distribution
Ezetimibe and ezetimibe-glucuronide are highly bound (>90%) to human plasma proteins.
Metabolism and Excretion
Ezetimibe is primarily metabolized in the small intestine and liver via glucuronide conjugation (a phase II reaction) with subsequent biliary and renal excretion. Minimal oxidative metabolism (a phase I reaction) has been observed in all species evaluated.
In humans, ezetimibe is rapidly metabolized to ezetimibe-glucuronide. Ezetimibe and ezetimibe-glucuronide are the major drug-derived compounds detected in plasma, constituting approximately 10 to 20% and 80 to 90% of the total drug in plasma, respectively. Both ezetimibe and ezetimibe-glucuronide are eliminated from plasma with a half-life of approximately 22 hours for both ezetimibe and ezetimibe-glucuronide. Plasma concentration-time profiles exhibit multiple peaks, suggesting enterohepatic recycling.
Following oral administration of 14C-ezetimibe (20 mg) to human subjects, total ezetimibe (ezetimibe + ezetimibe-glucuronide) accounted for approximately 93% of the total radioactivity in plasma. After 48 hours, there were no detectable levels of radioactivity in the plasma.
Approximately 78% and 11% of the administered radioactivity were recovered in the feces and urine, respectively, over a 10-day collection period. Ezetimibe was the major component in feces and accounted for 69% of the administered dose, while ezetimibe-glucuronide was the major component in urine and accounted for 9% of the administered dose.
Specific Populations
Geriatric Patients
In a multiple-dose study with ezetimibe given 10 mg once daily for 10 days, plasma concentrations for total ezetimibe were about 2-fold higher in older (≥65 years) healthy subjects compared to younger subjects.
Pediatric Patients
[See Use In Specific Populations (8.4).]
Gender
In a multiple-dose study with ezetimibe given 10 mg once daily for 10 days, plasma concentrations for total ezetimibe were slightly higher (<20%) in women than in men.
Race
Based on a meta-analysis of multiple-dose pharmacokinetic studies, there were no pharmacokinetic differences between Black and Caucasian subjects. Studies in Asian subjects indicated that the pharmacokinetics of ezetimibe were similar to those seen in Caucasian subjects.
Hepatic Impairment
After a single 10-mg dose of ezetimibe, the mean AUC for total ezetimibe was increased approximately 1.7-fold in patients with mild hepatic impairment (Child-Pugh score 5 to 6), compared to healthy subjects. The mean AUC values for total ezetimibe and ezetimibe were increased approximately 3- to 4-fold and 5- to 6-fold, respectively, in patients with moderate (Child-Pugh score 7 to 9) or severe hepatic impairment (Child-Pugh score 10 to 15). In a 14-day, multiple-dose study (10 mg daily) in patients with moderate hepatic impairment, the mean AUC values for total ezetimibe and ezetimibe were increased approximately 4-fold on Day 1 and Day 14 compared to healthy subjects. Due to the unknown effects of the increased exposure to ezetimibe in patients with moderate or severe hepatic impairment, ezetimibe is not recommended in these patients [see Warnings and Precautions (5.4)].
Renal Impairment
After a single 10-mg dose of ezetimibe in patients with severe renal disease (n=8; mean CrCl ≤30 mL/min/1.73 m2), the mean AUC values for total ezetimibe, ezetimibe-glucuronide, and ezetimibe were increased approximately 1.5-fold, compared to healthy subjects (n=9).
Drug Interactions
[See also Drug Interactions (7)]
Ezetimibe had no significant effect on a series of probe drugs (caffeine, dextromethorphan, tolbutamide, and IV midazolam) known to be metabolized by cytochrome P450 (1A2, 2D6, 2C8/9 and 3A4) in a "cocktail" study of twelve healthy adult males. This indicates that ezetimibe is neither an inhibitor nor an inducer of these cytochrome P450 isozymes, and it is unlikely that ezetimibe will affect the metabolism of drugs that are metabolized by these enzymes.
TABLE 4: Effect of Co-Administered Drugs on Total Ezetimibe | Co-Administered Drug and Dosing Regimen | Total Ezetimibe Based on 10 mg dose of ezetimibe |
|---|
| Change in AUC | Change in Cmax |
|---|
Cyclosporine-stable dose required (75–150 mg BID) See DRUG INTERACTIONS (7). ,Post-renal transplant patients with mild impaired or normal renal function. In a different study, a renal transplant patient with severe renal insufficiency (creatinine clearance of 13.2 mL/min/1.73 m2) who was receiving multiple medications, including cyclosporine, demonstrated a 12-fold greater exposure to total ezetimibe compared to healthy subjects. | ↑240% | ↑290% |
Fenofibrate, 200 mg QD, 14 days | ↑48% | ↑64% |
Gemfibrozil, 600 mg BID, 7 days | ↑64% | ↑91% |
Cholestyramine, 4 g BID, 14 days | ↓55% | ↓4% |
Aluminum & magnesium hydroxide combination antacid, single dose Supralox, 20 mL | ↓4% | ↓30% |
Cimetidine, 400 mg BID, 7 days | ↑6% | ↑22% |
Glipizide, 10 mg, single dose | ↑4% | ↓8% |
Statins | | |
Lovastatin 20 mg QD, 7 days | ↑9% | ↑3% |
Pravastatin 20 mg QD, 14 days | ↑7% | ↑23% |
Atorvastatin 10 mg QD, 14 days | ↓2% | ↑12% |
Rosuvastatin 10 mg QD, 14 days | ↑13% | ↑18% |
Fluvastatin 20 mg QD, 14 days | ↓19% | ↑7% |
TABLE 5: Effect of Ezetimibe Co-Administration on Systemic Exposure to Other Drugs | Co-Administered Drug and its Dosage Regimen | Ezetimibe Dosage Regimen | Change in AUC of Co-Administered Drug | Change in Cmax of Co-Administered Drug |
|---|
Warfarin, 25 mg single dose on day 7 | 10 mg QD, 11 days | ↓2% (R-warfarin) ↓4% (S-warfarin) | ↑3% (R-warfarin) ↑1% (S-warfarin) |
Digoxin, 0.5 mg single dose | 10 mg QD, 8 days | ↑2% | ↓7% |
Gemfibrozil, 600 mg BID, 7 days See Drug Interactions (7). | 10 mg QD, 7 days | ↓1% | ↓11% |
Ethinyl estradiol & Levonorgestrel, QD, 21 days | 10 mg QD, days 8 to 14 of 21d oral contraceptive cycle | Ethinyl estradiol 0% Levonorgestrel 0% | Ethinyl estradiol ↓9% Levonorgestrel ↓5% |
Glipizide, 10 mg on days 1 and 9 | 10 mg QD, days 2 to 9 | ↓3% | ↓5% |
Fenofibrate, 200 mg QD, 14 days | 10 mg QD, 14 days | ↑11% | ↑7% |
Cyclosporine, 100 mg single dose day 7 | 20 mg QD, 8 days | ↑15% | ↑10% |
Statins | | | |
Lovastatin 20 mg QD, 7 days | 10 mg QD, 7 days | ↑19% | ↑3% |
Pravastatin 20 mg QD, 14 days | 10 mg QD, 14 days | ↓20% | ↓24% |
Atorvastatin 10 mg QD, 14 days | 10 mg QD, 14 days | ↓4% | ↑7% |
Rosuvastatin 10 mg QD, 14 days | 10 mg QD, 14 days | ↑19% | ↑17% |
Fluvastatin 20 mg QD, 14 days | 10 mg QD, 14 days | ↓39% | ↓27% |