A Study to Evaluate the Effect of Intravenous Zanamivir on Cardiac Conduction in Healthy Volunteers

Inclusion Criteria: * Healthy as determined by a responsible and experienced physician, based on a medical evaluation including medical history, physical examination, laboratory tests and cardiac monitoring. * Male or female between 18 and 55 years of age inclusive, at the time of signing the informed consent. * A female subject is eligible to participate if she is of non-childbearing potential defined as pre-menopausal females with a documented tubal ligation or hysterectomy; or postmenopausal defined as 12 months of spontaneous amenorrhea or of child-bearing potential and agrees to use one of the contraception methods listed in the protocol. * Body weight greater than or equal to 50 kg for men and greater than or equal to 45 kg for women and BMI within the range 18.5-31.0 kg/m2 (inclusive). * AST, ALT, alkaline phosphatase and bilirubin less than or equal to 1.5xULN (isolated bilirubin \>1.5x upper limit of normal (ULN) is acceptable if bilirubin is fractionated and direct bilirubin \<35%). * Capable of giving written informed consent, which includes agreement to comply with the requirements and restrictions listed in the consent form Exclusion Criteria: * The subject has a positive pre-study drug/alcohol screen. A minimum list of drugs that will be screened for include amphetamines, barbiturates, cocaine, opiates, cannabinoids and benzodiazepines. * The subject has participated in a clinical trial and has received an investigational product within the following time period prior to the first dosing day in the current study: 30 days, 5 half-lives or twice the duration of the biological effect of the investigational product (whichever is longer). * History of sensitivity to any of the study medications, or components thereof, or a history of drug or other allergy that, in the opinion of the investigator or GSK Medical Monitor, contraindicates their participation. * Use of prescription or non-prescription drugs, including vitamins, herbal and dietary supplements (including St John's Wort) within 7 days (or 14 days if the drug is a potential enzyme inducer) or 5 half-lives (whichever is longer) prior to the first dose of study medication, unless in the opinion of the Investigator and GSK Medical Monitor the medication will not interfere with the study procedures or compromise subject safety. * A history of sensitivity to heparin or heparin-induced thrombocytopenia should not be enrolled. * History of regular alcohol consumption within 6 months of the study defined as an average weekly intake of \>14 drinks/week for men or \>7 drinks/week for women. * Has a history or regular use of tobacco- or nicotine-containing products within 3 months prior to screening. * Pregnant females as determined by positive serum or urine human chorionic gonadotrophin (hCG) test at screening or prior to dosing. * Lactating females. * Unwillingness or inability to follow the procedures outlined in the protocol. * Subjects with a pre-existing condition interfering with normal gastrointestinal anatomy or motility, hepatic and/or renal function, that could interfere with the absorption, metabolism, and/or excretion of the study drugs. Subjects with a history of cholecystectomy, inflammatory bowel disease or pancreatitis should be excluded. Subjects with active peptic ulcer disease or a history of upper gastrointestinal bleeding * A creatinine clearance less than 80mL/min as determined by Cockcroft-Gault equation. * History/evidence of clinically significant pulmonary disease, renal or hepatobiliary diseases. Subjects with a history of nephrolithiasis will be excluded. * A positive pre-study Human immunodeficiency virus (HIV) antibody test, a positive Hepatitis B surface antigen or Hepatitis C antibody result within 3 months of screening. * Where participation in the study would result in donation of blood or blood products in excess of 500 mL within a 56 day period. * Subjects with a hemoglobin \<11 g/dL. A single repeat is allowed for eligibility determination. * The subject's systolic blood pressure is outside the range of 90-140mmHg, or diastolic blood pressure is outside the range of 45-90mmHg or heart rate is outside the range of 45-100bpm for female subjects or 45-100 bpm for male subjects. * Exclusion criteria for screening ECG (a single repeat is allowed for eligibility determination) per protocol.