A Phase III, Randomized, Double-Blind, Placebo-Controlled Study Evaluating the Safety and Efficacy of Dexmedetomidine for Sedation During Monitored Anesthesia Care

Inclusion Criteria:

- Adult (> 18 years of age)

- American Society of Anesthesiologists (ASA) Physical Status I, II, III, or IV

- Subject requires MAC in an operating room (OR) or procedure room with an
anesthesiologist in attendance

- Subject requires an elective surgery/procedure expected to take longer than 30
minutes

- Subject requires local anesthetic block

Exclusion Criteria:

- Exposure to any experimental drug within 30 days prior to study drug administration

- Requires endotracheal intubation or laryngeal mask airway (LMA)

- Central nervous system (CNS) disease with an anticipated potential for increased
intracranial pressure, an uncontrolled seizure disorder, and/or known psychiatric
illness that could confound a normal response to sedative treatment

- Requires epidural or spinal anesthesia

- Received treatment with an alpha-2 agonist or antagonist within 14 days of the
scheduled surgery/procedure

- Subject for whom opiates, benzodiazepines, DEX, or other alpha-2 agonists are
contraindicated

- Subject has received an intravenous (IV) opioid within one hour, or a by mouth
(PO)/intramuscular (IM) opioid within four hours, of the start of study drug
administration

- Subject has acute unstable angina, acute myocardial infarction documented by
laboratory findings in the past six weeks, heart rate < 50 bpm, systolic blood
pressure (SBP) < 90 mmHg, or third-degree heart block unless patient has a pacemaker

- Subject has known elevated SGPT (ALT) and/or SGOT (AST) values of > 2 times the upper
limit of normal (ULN) within the two months prior to screening, and/or a history of
liver failure

- Subject has any other condition or factor which, in the Investigator's opinion, might
increase the risk to the subject