Revised CDC guidance on flu antivirals stresses early treatment

Sep 8, 2009 (CIDRAP News) – Revised recommendations from federal health officials on the use of influenza antiviral drugs suggest that clinicians consider providing prescriptions over the phone for high-risk patients as a way to start treatment faster if they come down with flu symptoms.

At the same time, the recommendations released today from the Centers for Disease Control and Prevention (CDC) suggest that clinicians try "watchful waiting" when high-risk patients have been exposed to flu but remain healthy, rather than prescribing a preventive antiviral right away. The recommendations cover both pandemic H1N1 and seasonal flu.

The CDC said the main message of the revised guidance is the same as recommendations issued back in May, early in the novel H1N1 flu outbreak: that the drugs should primarily be used for hospitalized patients and those who have flu-like illness and are at risk for complications. The recommendations mainly pertain to oseltamivir (Tamiflu) and zanamivir (Relenza).

"A critical reminder is that the vast majority of us who have an influenza-like illness don't need an antiviral," said Dr. Anne Schuchat, director of the CDC's National Center for Immunization and Respiratory Diseases, at a CDC press briefing this afternoon.

She warned that if most flu patients took antivirals, it could increase novel H1N1 resistance to the drugs. "We've seen a bit of resistance already. We're optimistic it won't take off, but it's important to use these antivirals carefully," she said.

While the main emphasis is on using antivirals for treating the sick, preventive use can be considered for people in high-risk groups and health workers who have had possible exposure to flu, the CDC says.

At the news briefing, Schuchat stressed the importance of early treatment, noting that oseltamivir or zanamivir therapy must be started within 48 hours after illness onset to maximize effectiveness.

"A key point is that hospitalized patients need prompt treatment with antiviral medication. That can be an important way to reduce the severity of illness," she said. She made the same point about high-risk patients who have symptoms.

For these groups of patients, Schuchat said, "We don't want providers to wait until test results are available."

Those at risk for complications include children younger than 5 years (especially those under 2 years), adults 65 or older, pregnant women, people with certain chronic medical or immunosuppressive conditions (eg, asthma, diabetes, lung disease), and those under age 19 who are on long-term aspirin therapy.

In summarizing the recommendations, Schuchat suggested that clinicians consider educating high-risk patients in advance and  consider planning to prescribe antivirals over the phone if patients get sick.

"Many people with chronic conditions and especially pregnant women see their provider frequently, so we think it is reasonable to have a conversation about what to do if flu symptoms occur, and that many providers may want to discuss with the patients the idea of providing a prescription that, upon a phone consultation, might be filled," she said.

The revised guidance counsels a cautious approach to prophylactic use of antivirals, even for high-risk patients.

Such use can be considered for high-risk patients who have been exposed to someone who was probably infected, says a CDC question-and-answer document also released today. But it adds, "As an alternative to prophylaxis, clinicians can also choose to counsel people at higher risk for influenza-related complications about the early signs and symptoms of influenza and advise them to immediately contact a health care provider for evaluation and possible early treatment if clinical signs or symptoms develop."

The guidance offers similar advice about healthcare, public health, and emergency workers who have been exposed to someone with confirmed or suspected flu. The CDC advises that workers use personal protective equipment and other precautions to minimize such exposures.

In response to a reporter's question about antiviral supplies, Schuchat implied that supplies might run short if preventive use of the drugs is widespread. "We think that the supply of antivirals in the system is adequate for any use of antivirals for treatment," she said, before reiterating that most people will not need the drugs.

"We think that by working together with the private sector and the public sector that we can have a good supply where we need it," she added.

In response to other questions, Schuchat listed warning signs in children that signal possible serious illness and a possible need for antiviral treatment. They include rapid or troubled breathing, bluish skin color, not drinking enough fluid, not waking up, not interacting in a normal way, "being so irritable that the child doesn't want to be held," and symptoms getting better and then getting worse.

In other comments, Schuchat said resistant strains of seasonal H1N1 flu have not been seen in the southern hemisphere in recent months. Seasonal H1N1 resistance to oseltamivir was widespread in the northern hemisphere last winter.

"We have had a lot of H1N1 seasonal strains the past year that were resistant. We are not seeing those strains in the southern hemisphere, so . . . we didn't have to incorporate that into our new guidance," she said.

In an H1N1 update at the beginning of the news briefing, Schuchat said 24 schools with about 25,000 students closed on Sep 4 because of outbreaks. The schools were in Georgia, Indiana, Missouri, and Tennessee. The CDC reported earlier that H1N1 cases were increasing in the Southeast, possibly because many schools opened earlier there than elsewhere in the country.

See also:

CDC question-and-answer report on revised recommendations on the use of flu antivirals in the 2009-10 seaons
http://www.cdc.gov/h1n1flu/antiviral.htm

Full text of CDC recommendations
http://www.cdc.gov/h1n1flu/recommendations.htm

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