Nebivolol is one of a class of drugs known as beta-blockers. These drugs are useful in the treatment of high blood pressure, angina, abnormal heart rhythms and following a heart attack. The purpose of this study is to explore the potential of nebivolol to cause a certain type of abnormal heart rhythm, known as QTc prolongation. The potential of nebivolol to cause this adverse event will be compared to three other drugs: atenolol, a beta-blocker approved by the FDA; Avelox (moxifloxacin), an anti-biotic approved for use by the FDA which is known to cause QTc prolongation; and placebo, a drug look-alike that contains no drug. The working hypothesis was that 20 or 40 mg of nebivolol would not prolong corrected QT intervals measured during peak nebivolol concentrations (i.e., 2 hours after dosing) on Day 7.

Inclusion Criteria:

• Men and nonpregnant, nonlactating women were 18 years or older.
• Women declaring postmenopausal or surgical sterility.
• Women of childbearing potential who had a negative serum HCG within 2 weeks of dosing.
• Male subjects weighed at least 60 kg (132 lb), and female subjects weighed at least 48 kg (106 lb). All volunteers weighed within 15% of their ideal body weight (IBW).

Exclusion Criteria:

• Institutionalized

• Reported or was known to have done the following:

  • Used any tobacco product.
  • Ingested any alcoholic, caffeine or xanthine containing food or beverage within the 48 hours prior to the initial dose of study medication
  • Consumed grapefruit or grapefruit containing products within 7 days prior to the initial dose of study medication.
  • Ingested any vitamins or herbal products within the 48 hours prior to the initial dose of study medication.
  • Recently changed dietary or exercise habits significantly

• Used any medication (including over-the-counter [OTC]) within the 14 days prior to the initial dose of study medication.

• Used any medication known to alter hepatic enzyme activity within 28 days prior to the initial dose of study medication.

• Received an investigational drug within 30 days prior to the initial dose of study medication.

• History of any significant cardiovascular, hepatic, renal, pulmonary, hematologic, gastrointestinal, endocrine, immunologic, dermatologic, or neurologic disease.

• History of drug and/or alcohol abuse within 1 year prior to the study.

• Acute illness at the time of either the pre study medical evaluation or dosing.

• Any laboratory results deemed clinically significant by the physician.

• Abnormal and clinically relevant ECG tracing.

• Donated or lost a significant volume of blood or plasma (>450 mL) within 28 days prior to the initial dose of study medication.

• Allergic or hypersensitive to nebivolol, atenolol, or other β blocking drugs or to moxifloxacin or other quinolone antibiotics.

• History of seizures or cerebrovascular disease.