Pharmacist counters CDC antivirals for flu alert

The Centers for Disease Control’s new guidance that hospitalized and high-risk patients with unconfirmed but suspected flu should be administered antivirals without waiting may cause additional medication shortages, according to a pharmacist and professor.

“When indicated, antiviral treatment should be started as soon as possible after illness onset and should not be delayed even for a few hours to wait for the results of testing, the CDC wrote in its recent Health Alert Network email. Ideally, treatment should be initiated within 48 hours of symptom onset, according to the agency. “However, antiviral treatment initiated later than 48 hours after illness onset can still be beneficial for some patients,” according to the alert.

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In fact, a randomized placebo controlled study suggested clinical benefit when oseltamivir was initiated 72 hours after illness onset among febrile children with uncomplicated influenza. “Clinical judgment, on the basis of the patient’s disease severity and progression, age, underlying medical conditions, likelihood of influenza, and time since onset of symptoms, is important when making antiviral treatment decisions for outpatients.”

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However, there currently is “no strong evidence” to support the use of antivirals in reducing hospital admission or severe complications in patients suspected of the flu, Clarence D. Moore, PharmD, assistant professor at Howard University College of Pharmacy, told FormularyWatch. “In fact, this recommendation may further diminish our short supply of Tamilfu and cause an increased amount of unwarranted adverse effects,” Dr Moore said.

Meanwhile, the CDC said that treatment should include one of the anti-flu medications: oseltamivir (Tamiflu), zanamivir (Relenza), or the intravenous drug peramivir (Rapivab), according to the alert.

Clinicians should also realize that a negative RIDT result does not exclude a diagnosis of influenza in a patient with suspected influenza. “The results of rapid influenza diagnostic tests (RIDTs; immunoassays that can identify the presence of influenza A and B viral nucleoprotein antigens in respiratory specimens) may not be accurate; test sensitivities are approximately 50% to 70% when compared with viral culture or reverse transcription-polymerase chain reaction (RT-PCR),” the CDC wrote.