Variability in Adrenergic Response

Condition(s) targeted: Vascular Reaction to Medications

Intervention: phenylephrine and nitroglycerin (Drug)

Phase: N/A

Status: Active, not recruiting

Sponsored by: Vanderbilt University

Official(s) and/or principal investigator(s):
Charles M Stein, MD, Principal Investigator, Affiliation: Vanderbilt University

The goal of this project is to determine the genetic factors contributing to interindividual differences in response to physiological and pharmacological vasoconstrictors and vasodilators.

Official title: Variability in Adrenergic Response

Study design: Endpoint Classification: Pharmacodynamics Study, Intervention Model: Single Group Assignment, Masking: Open Label

Primary outcome: sensitivity to phenylephrine and nitroglycerin

Secondary outcome: cardiovascular responses to cold and mental stress

Detailed description: The dorsal hand vein model is a relatively non-invasive and robust experimental model to examine the local in vivo effect of vasoactive drugs without elucidating systemic counterregulatory reflexes. Infusion of incremental low doses of phenylephrine into a dorsal hand vein results in increasing local venoconstriction, without systemic effects. Similarly, infusion of incremental low doses of nitroglycerin into a preconstricted dorsal hand vein results in increasing local venodilation, without systemic effects. Systemic vascular responses can be measured by the cold pressor test (CPT),that leads to increase in blood pressure and heart rate , or mental stress that is also known to stimulate cardiovascular responses. Individuals vary in their local and systemic vascular responses but the genetic determinants of these are not clear.

Minimum age: 18 Years. Maximum age: 40 Years. Gender(s): Both.

Criteria:

Inclusion Criteria:

- Age between 18 and 40 years, inclusive.

- Subject must be willing to give written informed consent and be able to adhere to

diet and study schedules.

- Subjects must be free of any clinically significant disease that requires a

physician's care and/or would interfere with the study evaluations.

- Subjects must have a normal or clinically acceptable physical examination and ECG.

- Clinical laboratory tests (CBC, blood chemistries, and urinalysis) must be within

normal limits or clinically acceptable to the investigator. Exclusion Criteria:

- Any subject who has taken any prescription or over-the-counter drugs, other than oral

contraception if female, within two weeks prior to study drug administration.

- Subjects who are presently, or were formerly, narcotic addicts or alcoholics.

- Subjects who have a clinically significant allergy/intolerance to phenylephrine.

- Females with a positive serum/urine pregnancy test at screening.

- Females who are nursing.

- Subject using sildenafil or other phosphodiesterase inhibitors.

Vanderbilt University Medical Center, Nashville, Tennessee 37232, United States

Starting date: January 2009
Last updated: June 16, 2015