Use of Piramivir in H1N1... experiences?

[Zookeeper3]

Well we're going off a CDC recomendation and giving Piramivir a try, anyone seeing success? Have a non confirmed tamiflu resistance and out of options, already maxed on the oscillator.

[indigo girl]

Sorry, I don't have any particular posts to offer on the use of this drug although I know that we have posted on a few cases that did use it in this forum. There are just too many posts here to find them, unfortunately...

I did read that drug resistance to piramivir has occurred already. Hopefully, this will only be a rare event, and luckily for the patient involved, zanamivir was still effective since Tamiflu had already failed. Just something to keep an eye on as the H275Y mutation was noted right since the beginning of the pandemic in a case that had NOT been treated with any of the antivirals.

http://www.cidrap.umn.edu/cidrap/content/influenza/swineflu/news/mar2610resistance.html

...When one patient's condition deteriorated after 24 days of oseltamivir treatment, doctors prescribed peramivir for 10 days, which did not reduce viral shedding or reverse the patient's infection. The patient recovered after doctors prescribed a 10-day course of zanamivir.

Anthony S. Fauci, MD, director of NIAID, said in a press release today that, while the emergence of drug resistance isn't surprising, the cases show that the strains can emerge after brief antiviral therapy. "We have a limited number of drugs available for treating influenza, and these findings provide additional urgency to efforts to develop antivirals that attack influenza virus in novel ways," he said.

Memoli said in the press release that more studies are needed to refine the group's findings. "But these cases of rapid appearance of drug-resistant 2009 H1N1 influenza in immune-compromised patients are worrisome and should prompt clinicians to reconsider how they use available flu drugs," he added.

Because the H275Y mutation also reduces susceptibility to peramivir, patients who develop resistant strains after a short course of oseltamivir might not respond to peramivir, Memoli said. Zanamivir might be a good choice when patients don't respond after a few days of oseltamivir treatment, but patients who are very ill and on mechanical ventilation can't receive the inhaled drug.

The authors also recommend more studies to investigate the effectiveness of peramivir in patients who don't respond to oseltamivir.

(hat tip Avian Flu Diary)