Lack of effect of colesevelam HCl on the single-dose pharmacokinetics of aspirin, atenolol, enalapril, phenytoin, rosiglitazone, and sitagliptin

AIMS

Drug interactions with bile acid sequestrants are primarily due to the potential of these agents to bind to concomitant drugs. Six clinical studies were performed to determine the effects of colesevelam on the pharmacokinetics of aspirin, atenolol, enalapril, phenytoin, rosiglitazone, and sitagliptin.

METHODS

All six studies enrolled healthy subjects aged 18-45 years. The phenytoin study used a single-dose, three-period crossover design (phenytoin alone, phenytoin simultaneously with colesevelam, and phenytoin 4h before colesevelam). The other studies used a two-period crossover design (test drug alone and test drug simultaneously with colesevelam). Colesevelam (3750mg once daily) was dosed throughout the pharmacokinetic sampling period. After each single dose of the test drug, serial blood samples were collected for determination of plasma drug concentrations and calculation of pharmacokinetic parameters.

RESULTS

For all six test drugs, 90% CIs for geometric least-squares mean ratios of AUC and Cmax for the measured analytes were within specified limits, indicating no interaction between the test drug and colesevelam.

CONCLUSIONS

Aspirin, atenolol, enalapril, rosiglitazone, and sitagliptin may be taken with colesevelam. Although the phenytoin study indicated no pharmacokinetic interaction, phenytoin should continue to be taken ≥4h before colesevelam in accordance with current prescribing information.

The effects of colesevelam HCl on the single-dose pharmacokinetics of glimepiride, extended-release glipizide, and olmesartan medoxomil

Bile acid sequestrants can potentially bind to concomitant drugs. Single-dose studies evaluated the effects of colesevelam on the pharmacokinetics of glimepiride, glipizide extended-release (ER), and olmesartan medoxomil. Each study enrolled healthy subjects aged 18-45 years. The olmesartan medoxomil study used a randomized adaptive crossover design that initially compared olmesartan medoxomil alone versus simultaneously with colesevelam, then olmesartan medoxomil alone versus 4 hours before colesevelam. The other studies used a three-period crossover design (test drug alone, test drug simultaneously with colesevelam, and test drug 4 hours before colesevelam). For the colesevelam coadministration periods, 3,750 mg once daily was dosed throughout the pharmacokinetic sampling period. After each single dose of test drug, serial blood samples were collected for determination of plasma drug concentrations and calculation of pharmacokinetic parameters. Administering colesevelam simultaneously with glimepiride or glipizide ER resulted in minor reductions (18% and 13%, respectively) in total exposure that were negated by staggering colesevelam dosing by 4 hours. Administering colesevelam simultaneously with olmesartan medoxomil resulted in a major reduction (39%) in olmesartan exposure that was reduced by staggering colesevelam dosing by 4 hours. This reduction in olmesartan exposure is not predicted to have a clinically significant impact on blood pressure control.

Clinical safety, tolerability, pharmacokinetics, and pharmacodynamics of the novel factor Xa inhibitor edoxaban in healthy volunteers

This is a clinical safety, tolerability, pharmacokinetics (PK), and pharmacodynamics (PD) study of a single ascending dose (SAD) and a multiple ascending dose (MAD) of the oral direct factor Xa inhibitor edoxaban in healthy males. The placebo-controlled, single-blind, randomized, 2-part study consists of a SAD arm with 85 subjects (10, 30, 60, 90, 120, 150 mg) and a MAD arm with 36 subjects (90 mg daily, 60 mg twice daily, 120 mg daily). Effects of food and formulation (tablet vs solution) are assessed in a crossover substudy. In the SAD, doses are well tolerated up to 150 mg. Exposure is proportional to dose. PK profiles are consistent across dose with rapid absorption, biphasic elimination, and terminal elimination half-life of 5.8 to 10.7 hours. In the MAD, mean accumulation after daily dosing is 1.10 to 1.13 and consistent with elimination half-life of 8.75 to 10.4 hours. Intrasubject variability ranges from 12% to 17% for area under the curve. In general, plasma edoxaban concentrations are linearly correlated with coagulation parameters. Edoxaban is safe and well tolerated with no dose-dependent increases in adverse events. It is concluded that single and multiple doses of edoxaban are safe and well tolerated up to 150 mg with predictable PK and PD profiles.