Effect of ticagrelor on the pharmacokinetics of ethinyl oestradiol and levonorgestrel in healthy volunteers

Effects of Lemborexant on the Pharmacokinetics of Oral Contraceptives: Results From a Phase 1 Drug-Drug Interaction Study in Healthy Females

Lemborexant is a dual orexin receptor antagonist approved in multiple countries including the United States, Canada, and Japan for the treatment of insomnia in adults. As women of childbearing potential may be prescribed insomnia drugs, a drug‐drug interaction study was conducted. This single‐center, open‐label, fixed‐sequence study examined potential drug‐drug interactions between lemborexant and an oral contraceptive (OC) in healthy females (18–44 years, n = 20). The purpose of this study was to determine the effect of lemborexant 10 mg (at steady state) on the pharmacokinetics of a single dose of OC (0.03 mg ethinyl estradiol and 1.5 mg norethindrone acetate), assess the effect of a single dose of OC on lemborexant pharmacokinetics, and evaluate safety and tolerability of lemborexant and OC coadministration. Ethinyl estradiol maximum plasma drug concentration was not altered by lemborexant coadministration; area under the curve from zero time to the last quantifiable concentration was slightly increased, by 13%. No clinically relevant effects on norethindrone acetate pharmacokinetics were observed. Coadministration of OC with lemborexant had no clinically relevant effect on the steady‐state pharmacokinetics of lemborexant. Adverse events were consistent with the known safety profile. These results support the conclusion that lemborexant and OC can be coadministered without dose adjustment.

Effects of ticagrelor on the pharmacokinetics of rivaroxaban in rats

CONTEXT

Rivaroxaban and ticagrelor are two common drugs for the treatment of atrial fibrillation and acute coronary syndrome. However, the drug-drug interaction between them is still unknown.

OBJECTIVE

To investigate the effects of ticagrelor on the pharmacokinetics of rivaroxaban in rats both in vivo and in vitro.

MATERIALS AND METHODS

A sensitive and reliable UPLC-MS/MS method was developed for the determination of rivaroxaban in rat plasma. Ten Sprague-Dawley rats were randomly divided into ticagrelor pre-treated group (10 mg/kg/day for 14 days) and control group. The pharmacokinetics of orally administered rivaroxaban (10 mg/kg, single dose) with or without ticagrelor pre-treatment was investigated with developed UPLC-MS/MS method. Additionally, Sprague-Dawley rat liver microsomes were also used to investigate the drug-drug interaction between these two drugs in vitro.

RESULTS

The C _max (221.34 ± 53.33 vs. 691.18 ± 238.31 ng/mL) and the AUC_(0-t) (1060.97 ± 291.21 vs. 3483.03 ± 753.83 μg·h/L) of rivaroxaban increased significantly (p < 0.05) with ticagrelor pre-treatment. The MRT_(0-∞) of rivaroxaban increased from 4.41 ± 0.79 to 5.97 ± 1.11 h, while the intrinsic clearance decreased from 9.93 ± 2.55 to 2.89 ± 0.63 L/h/kg (both p < 0.05) after pre-treated with ticagrelor. Enzyme kinetic study indicated that ticagrelor decreased rivaroxaban metabolic clearance with the IC₅₀ value of 14.04 μmol/L.

CONCLUSIONS

Our in vivo and in vitro results demonstrated that there is a drug-drug interaction between ticagrelor and rivaroxaban in rats. Further studies need to be carried out to verify whether similar interactions truly apply in humans and whether these interactions have clinical significance.

Perspectives on variability in pharmacokinetics of an oral contraceptive product

The early literature and reviews have described the pharmacokinetics (PK) of oral contraceptive (OC) compounds such as ethinyl estradiol (EE) and levonorgestrel (LNG) in women as subject to large intersubject variability. This was partly due to the use of diverse radioimmunoassays, limited sampling periods and an incomplete understanding of single- vs. multiple-dose kinetics and the role of EE in causing both inhibition of hepatic metabolism along with induction of sex hormone binding globulin. Over the past two decades, LNG and EE have been used as target drugs for the assessment of possible drug interactions upon introduction of many new therapeutic agents. This has resulted in at least 17 publications that describe the PK of LNG and EE in women using various 150 mcg/30 mcg products under fairly standard multiple-dose conditions. A review of these studies indicates only moderate variability in the C_max and area under the curve both within and across these studies. There is impressive similarity in these drug exposure indices found in studies carried out with several products by investigators at numerous sites and countries.

Ticagrelor: Pharmacokinetic, Pharmacodynamic and Pharmacogenetic Profile: An Update

Despite advancements in treatments for acute coronary syndromes over the last 10 years, they continue to be life-threatening disorders. Currently, the standard of treatment includes dual antiplatelet therapy consisting of aspirin plus a P2Y12 receptor antagonist. The thienopyridine class of P2Y12 receptor antagonists, clopidogrel and prasugrel, have demonstrated efficacy. However, their use is associated with several limitations, including the need for metabolic activation and irreversible P2Y12 receptor binding causing prolonged recovery of platelet function. In addition, response to clopidogrel is variable and efficacy is reduced in patients with certain genotypes. Although prasugrel is a more consistent inhibitor of platelet aggregation than clopidogrel, it is associated with an increased risk of life-threatening and fatal bleeding. Ticagrelor is an oral antiplatelet agent of the cyclopentyltriazolopyrimidine class and also acts through the P2Y12 receptor. In contrast to clopidogrel and prasugrel, ticagrelor does not require metabolic activation and binds rapidly and reversibly to the P2Y12 receptor. In light of new data, this review provides an update on the pharmacokinetic, pharmacodynamic and pharmacogenetic profiles of ticagrelor in different study populations. Recent studies report that no dose adjustment for ticagrelor is required on the basis of age, gender, ethnicity, severe renal impairment or mild hepatic impairment. The non-P2Y12 actions of ticagrelor are reviewed, showing indirect positive effects on cellular adenosine concentration and biological activity, by inhibition of equilibrative nucleoside transporter-1 independently of the P2Y12 receptor. CYP2C19 and ABCB1 genotypes do not appear to influence ticagrelor pharmacodynamics. A summary of drug interactions is also presented.

Clinical drug-drug interaction assessment of ivacaftor as a potential inhibitor of cytochrome P450 and P-glycoprotein

Ivacaftor is approved in the USA for the treatment of cystic fibrosis (CF) in patients with a G551D-CFTR mutation or one of eight other CFTR mutations. A series of in vitro experiments conducted early in the development of ivacaftor indicated ivacaftor and metabolites may have the potential to inhibit cytochrome P450 (CYP) 2C8, CYP2C9, CYP3A, and CYP2D6, as well as P-glycoprotein (P-gp). Based on these results, a series of clinical drug-drug interaction (DDI) studies were conducted to evaluate the effect of ivacaftor on sensitive substrates of CYP2C8 (rosiglitazone), CYP3A (midazolam), CYP2D6 (desipramine), and P-gp (digoxin). In addition, a DDI study was conducted to evaluate the effect of ivacaftor on a combined oral contraceptive, as this is considered an important comedication in CF patients. The results indicate ivacaftor is a weak inhibitor of CYP3A and P-gp, but has no effect on CYP2C8 or CYP2D6. Ivacaftor caused non-clinically significant increases in ethinyl estradiol and norethisterone exposure. Based on these results, caution and appropriate monitoring are recommended when concomitant substrates of CYP2C9, CYP3A and/or P-gp are used during treatment with ivacaftor, particularly drugs with a narrow therapeutic index, such as warfarin.

The effect of ticagrelor on the metabolism of midazolam in healthy volunteers

BACKGROUND

In vitro studies have demonstrated that ticagrelor, an oral antiplatelet agent, is a substrate, activator, and inhibitor of cytochrome P450 (CYP) 3A. Thus, potential CYP3A-mediated drug-drug interactions may occur.

OBJECTIVES

The goal of this article was to report study results on the effect of ticagrelor on the pharmacokinetics of oral midazolam (oral midazolam study) and oral versus intravenous (IV) midazolam (oral/IV midazolam study). Secondary objectives included assessing the effect of midazolam on ticagrelor pharmacokinetic parameters, and the safety and tolerability of ticagrelor/midazolam coadministration.

METHODS

Two randomized crossover studies were conducted in healthy volunteers (n = 28 in each) with ticagrelor and midazolam. In the first study, volunteers received oral ticagrelor (400 mg daily) or placebo for 6 days, then oral midazolam (7.5 mg). The second study regimen was a single dose of ticagrelor 270 mg, then ticagrelor 180 mg BID for 6 days with a single oral (7.5 mg) or IV (2.5 mg) dose of midazolam.

RESULTS

After oral midazolam administration, ticagrelor significantly reduced the AUC(0-∞) of midazolam (30%-32%) and 4-hydroxymidazolam (42%-47%) but not 1-hydroxymidazolam. After administration of IV midazolam, ticagrelor reduced the AUC(0-∞) of midazolam (12%) and 4-hydroxymidazolam (23%) but not 1-hydroxymidazolam.

CONCLUSIONS

These results indicate that ticagrelor can weakly activate the metabolism of midazolam to its major 1'-hydroxy metabolite, and at the same time, seems to weakly inhibit midazolam 4'-hydroxylation. Furthermore, ticagrelor affects both hepatic and intestinal CYP3A activity.