A recent check of prescribing data from pharmacies around the state found that 15 percent of Tamiflu prescriptions were filled five days after they were written.

That means a lot of wasted Tamiflu, says Health Director David R. Gifford –– because the drug works only if you take it within a day or two after you start feeling ill.

Antivirals such as Tamiflu work differently than antibiotics. Antibiotics kill bacteria. But antivirals don’t kill viruses. Instead, they slow the replication of the virus. As a result, your symptoms will be less severe and your illness will go away faster. But if you wait until the virus has overrun your body, Tamiflu won’t help.

Tamiflu is recommended only in certain circumstances. Most people who get the swine flu don’t need it and shouldn’t get it. Overuse of Tamiflu could cause the H1N1 virus to become resistant to the drug. Also, if it’s prescribed to all the people who can easily recover, there may not be enough Tamiflu for those at risk of serious illness.

The U.S. Centers for Disease Control and Prevention recommends that doctors prescribe Tamiflu for people with severe symptoms, people who need hospitalization, children younger than 2, pregnant women up to two weeks postpartum, and people of any age with chronic health conditions.

If you or your child is in one of the high-risk groups, don’t delay in contacting your doctor at the first evidence of flu-like symptoms, such as a fever above 100.4 degrees, a cough, muscle aches and fatigue.

The state has been tracking Tamiflu prescriptions through the electronic prescribing system that is in place at every pharmacy. Gifford said that supplies have so far been adequate. Pharmacies that start to run out have been able to get it more quickly from the manufacturer. Additionally, the state has its own emergency stockpile of 75,000 doses that can be tapped if needed.

Meanwhile, the Health Department on Tuesday issued an alert cautioning consumers against confusing Tamiflu with Theraflu. Tamiflu can only be obtained by prescription. Theraflu is an over-the-counter medication that may reduce fever and ease body aches, but does nothing to lessen the severity or shorten the duration of flu. Additionally, some preparations of Theraflu have high doses of acetaminophen and are unsafe for children. Parents are urged to consult their pediatricians before giving Theraflu to children.

Felice J. FreyerVaccinations

The state began vaccinating children against swine flu at school-based clinics around the state this week. The clinics for Wednesday and Thursday are listed below. To find the date for the H1N1 swine flu clinic at your schools, check projo.com and look for “School-based flu shots start Nov. 2.” You can also search the clinics by town, date and school at http://www.health.ri.gov

Nov. 4

Bristol: Guiteras School

Central Falls: Ella Risk School (at Veterans Memorial Elementary)

Glocester: West Glocester Elementary

Middletown: Aquidneck School (at Gaudet Middle School)

North Kingstown: Forest Park Elementary School

North Kingstown: South County Montessori School

North Providence: Centredale School

Pawtucket: Nathanael Greene School

Pawtucket: Francis J. Varieur School

Smithfield: William Winsor School

Tiverton: Walter E. Ranger School

Warwick: Lippitt School

Warwick: Warwick Neck School

Woonsocket: Harris School

Nov. 5

Coventry: Western Coventry School

Cumberland: Community School (at Cumberland HS)

East Greenwich: George Hanaford School

Exeter-West Greenwich: Metcalf School

Pawtucket: Henry J. Winters School

Pawtucket: M. Virginia Cunningham School

Scituate: Fogarty Memorial School

Warwick: John Wickes School

Warwick: Park School