A Dose-ranging Study to Evaluate the Safety and Efficacy of LUSEDRA (Fospropofol Disodium) as an Intravenous Sedative for Diagnostic or Therapeutic Colonoscopy in Adult Special Populations

Subjects who meet all of the following criteria will be included in the study: 1. Male and female adult candidates for diagnostic or therapeutic colonoscopy with at least one of the following characteristics: * Subgroup 1: Weight \< 60 kg and age \>/= 18 to \< 65 years and ASA I or II; * Subgroup 2: Weight \< 60 kg and age \>/= 65 years and/or ASA 3 or 4; or * Subgroup 3: Weight \>/=60 kg and age \>/= 65 years and/or ASA 3 or 4. 2. Females of childbearing potential must have a negative beta human chorionic gonadotropin (?hCG) urine pregnancy test at Visit 1 (Screening) and prior to starting study drug (Visit 2). Female subjects of childbearing potential must agree to be abstinent or to use a highly effective methods of contraception (eg, condom + spermicide, condom + diaphragm with spermicide, intrauterine device \[IUD\], or have a vasectomised partner) having starting for at least 1 menstrual cycle prior to starting study drug and throughout the entire study period and for 30 days after the last dose of study drug. Those women using hormonal contraceptives must also be using an additional approved method of contraception (as described previously). Perimenopausal women must be amenorrheic for at least 12 months to be considered of non-childbearing potential; 3. Are willing and able to comply with all aspects of the protocol; and 4. Provide written informed consent. Subjects who meet any of the following criteria will be excluded from participation in the study: 1. Females who are pregnant (positive BhCG urine pregnancy test) or breastfeeding; 2. Subjects who do not meet nil per os (NPO) requirement of no solid foods within 8 hours and clear fluids up to 3 hours before the procedure (assessed only at Baseline); 3. Evidence of clinically significant disease or a history of a concomitant medical condition (eg, cardiac, respiratory, gastrointestinal, renal disease) that, in the opinion of the Investigator, could affect the subject's safety or ability to safely complete the study; 4. Subjects with hypersensitivity to LUSEDRA or any other components of LUSEDRA, including its active metabolite, propofol; 5. History of drug or alcohol dependency or abuse within approximately the last 2 years; or 6. The Investigator believes to be medically unfit to receive the study drug or unsuitable for any other reason.