Zanamivir Treatment of Vascular Permeability in Dengue (ZAP-DENGUE)

Inclusion Criteria: 1. Provision of signed and dated informed consent form. 2. Stated willingness to comply with all study procedures and availability for the duration of the study. 3. Male or female, aged \>7 years 4. Willingness to receive intravenous medication and be willing to adhere to the medication regimen 5. Have a diagnosis of dengue by dengue NS1 rapid test 6. Have had a self-informed fever \>38 degrees C in the last 3 days. 7. Have dengue with warning signs as per the 2009 WHO criteria including one of the following: abdominal pain or tenderness, persistent vomiting, clinical fluid accumulation, mucosal bleeding, lethargy, restlessness, liver enlargement over 2 cm, augmented hematocrit, thrombocytopenia or severe dengue defined as dengue with severe plasma leakage leading to dengue shock and/or fluid accumulation with respiratory distress; severe hemorrhage; severe organ impairment (hepatic damage, renal impairment, cardiomyopathy, encephalopathy or encephalitis). 8. Enrollment in EPS (Entidadas Promotoras de Salud) or Sistema General de Seguridad Social en Salud (SGSSS)- Colombian Public Health Insurance. Exclusion Criteria: 1. Pregnancy or lactation 2. Children in Care of the state 3. Patients who are unlikely to survive 48 hours 4. Unstable cardiac disease or arrhythmia at baseline 5. History of significant cardiac disease 6. Treatment with another investigational drug or other intervention within 1 month. 7. Encephalitis or unable to consent