An AE is defined as any unfavorable and unintended sign including an abnormal laboratory finding, symptom or disease associated with the use of a medical treatment or procedure, regardless of whether it is considered related to the medical treatment or procedure, that occurs during the course of the study.

An AE is defined as any unfavorable and unintended sign including an abnormal laboratory finding, symptom or disease associated with the use of a medical treatment or procedure, regardless of whether it is considered related to the medical treatment or procedure, that occurs during the course of the study. Abnormal laboratory hematology value was any AE reported under the System Organ Class of Investigations that was related to an abnormal laboratory hematology value.

An AE is defined as any unfavorable and unintended sign including an abnormal laboratory finding, symptom or disease associated with the use of a medical treatment or procedure, regardless of whether it is considered related to the medical treatment or procedure, that occurs during the course of the study. Abnormal laboratory chemistry value was any AE reported under the System Organ Class of Investigations that was related to an abnormal laboratory chemistry value.

An AE is defined as any unfavorable and unintended sign including an abnormal laboratory finding, symptom or disease associated with the use of a medical treatment or procedure, regardless of whether it is considered related to the medical treatment or procedure, that occurs during the course of the study. Abnormal laboratory urinalysis value was any AE reported under the System Organ Class of Investigations that was related to an abnormal laboratory urinalysis value.

Participants rested for at least 10 minutes prior to having vital sign measurements obtained.

Participants rested for at least 10 minutes prior to having vital sign measurements obtained. Heart rate measurements were obtained in the semirecumbent position and 3 sets of measurements were obtained approximately 1 minute apart.

An AE is defined as any unfavorable and unintended sign including an abnormal laboratory finding, symptom or disease associated with the use of a medical treatment or procedure, regardless of whether it is considered related to the medical treatment or procedure, that occurs during the course of the study. An abnormal ECG value was any AE reported under the System Organ Classes of Investigations or Cardiac that was related to an abnormal ECG value.

An adverse event (AE) is defined as any unfavorable and unintended sign including an abnormal laboratory finding, symptom or disease associated with the use of a medical treatment or procedure, regardless of whether it is considered related to the medical treatment or procedure, that occurs during the course of the study. Participants in Arms/Groups in which MK-8266 or placebo was administered in more than one period were counted separately for each period.

An adverse event (AE) is defined as any unfavorable and unintended sign including an abnormal laboratory finding, symptom or disease associated with the use of a medical treatment or procedure, regardless of whether it is considered related to the medical treatment or procedure, that occurs during the course of the study. Participants in Arms/Groups in which MK-8266 or placebo was administered in more than one period were counted separately for each period.

Central ascending aortic blood pressure augmentation index (AIx) is the percentage of the central pulse pressure attributed to the reflected pulse wave, and is an indirect measure of systemic arterial stiffness. AIx can be measured non-invasively by radial tonometry using aplanation tonometry of radial artery with the SphygmoCor Pulse Wave Analysis System Guide (SphygmoCor system). AIx was performed at prestudy to ensure an adequate waveform can be obtained. At each time point, a minimum of 2 AIx were completed in an attempt to obtain 2 acceptable quality assessments. A time weighted average was calculated. AIx was adjusted for heart rate. A decrease in the AIx of ≥5 percentage is considered clinically meaningful. Participants in Arms/Groups in which MK-8266 or placebo was administered in more than one period were counted separately for each period. The 12-hour measurement was not collected (per protocol) in all periods of Panels A and B.

PK is the process by which a drug is absorbed, distributed, metabolized, and eliminated by the body. AUC\[0-inf\] is a measure of the mean concentration levels of drug in the plasma after the dose. AUC\[0-inf\] was not collected, analyzed or summarized for participants receiving placebo.

PK is the process by which a drug is absorbed, distributed, metabolized, and eliminated by the body. Cmax is a measure of the maximum amount of drug in the plasma after the dose is given. For Panel A 1.0/0.8 mg MK-8266, the second dose was not well characterized due to limited sampling. Observed exposure likely underestimates the true exposure. Cmax was not collected, analyzed or summarized for participants receiving placebo.

PK is the process by which a drug is absorbed, distributed, metabolized, and eliminated by the body. Tmax is a measure of the time to reach the maximum concentration in the plasma after the drug dose. Tmax was not collected, analyzed or summarized for participants receiving placebo.

PK is the process by which a drug is absorbed, distributed, metabolized, and eliminated by the body. t1/2 is the time required for a given drug concentration in the plasma to decrease by 50%. Harmonic means +/- Pseudo standard deviations are displayed. t1/2 was not collected, analyzed or summarized for participants receiving placebo.