Based on the current news stories circulating, it seems that Tamiflu is losing some of its capability as a neuraminidase inhibitor. Instead of spending a lot of money stockpiling this drug, shouldn’t we focus more on vaccine development and vaccine production infrastructure?
yes. Please asee on the main page of the wiki, right, the non-pharmacological approach advocated by WHO.
There has always been more than tamiflu stockpiling to flu prep. Tamiflu may work, or may not. See also the tamiflu stockpiling page and Dr Woodson’s comments
SUMMARY
Influenza A (H5N1) virus with an amino acid substitution in neuraminidase conferring high-level resistance to oseltamivir was isolated from two of eight Vietnamese patients during oseltamivir treatment. Both patients died of influenza A (H5N1) virus infection, despite early initiation of treatment in one patient. Surviving patients had rapid declines in the viral load to undetectable levels during treatment. These observations suggest that resistance can emerge during the currently recommended regimen of oseltamivir therapy and may be associated with clinical deterioration and that the strategy for the treatment of influenza A (H5N1) virus infection should include additional antiviral agents.
also discussed here.
as I understand it, the virus will likely develope resistence when it goes through many bodies who were treated with antivirals. So the strategy should be to isolate people treated with antivirals, so the virus can’t escape those. But the essential workers, military etc. who probably get the antivirals first cannot be isolated, they are also treated prophylactically. Is the whole system doomed to fail ?
Have a look at Biota code BTA on the australian stock exch They made the very first neuradimase inhibitor - relenza and are in trials with the first third generation antiviral(long acting neuradimaze inhibitor)a version of relenza that only has to be taken once per week also looks like relenza may be the antiviral of choice soon as bird flu is becomming resistent to tamiflu in some studies while relenza has no resistence and several other advantages.once inhaled it goes straight to the lung and is fully active within minutes (very important when time is of the essence in trying to stop your immune system overreacting to the bird flu)also i read a new report today which has found that the virus gets deep into the alvioli of the lung - that would make relenza more effective than tamiflu which has been grabing all the haed lines to date
relenza has major advantages, but is confined to the lung whereas tamiflu hits the other organs that H5N1 does (relenza does not).
Any futher suggestions about stocks will be removed as spam.
I’m asthmatic and Relenza isn’t an option for me or for others with chronic lung disease.
I remember a post at curevents: the problem with Relenza is … Glaxo-Smithcline (also a stock) (they didn’t want it to be produced and sold ! )
when antivirals are taken prophylactically as with Relenza, then I guess the danger of resistent virus-strains is larger. The virus can infect, develope resistence and spread before the victim having symptoms. (right ?)
Can you take a combination of anti-virals at the same time?
Study suggests older antivirals could help fight H5N1 May 12, 2006 (CIDRAP News) – An analysis of more than 600 H5N1 avian influenza viruses collected from several Asian countries suggests that two older antiviral drugs could be more useful in fighting a flu pandemic triggered by H5N1 than previously believed.
Most H5N1 viruses collected from humans and poultry in Vietnam and Thailand have been resistant to the two older drugs, amantadine and rimantadine (known as the adamantanes). As a result, hopes for an effective drug have focused on the newer antivirals, oseltamivir and zanamavir. Many countries have been stockpiling oseltamivir.
But an international team of scientists is reporting that resistance to amantadine seems less common than has been believed, at least in some countries. As expected, they found that most viruses from Vietnam, Thailand, and Cambodia had mutations that signaled resistance to amantadine. But only a few of the viruses from China and Indonesia had those mutations.
“Amantadine appears to retain the potential to be useful in an H5N1 pandemic in the absence of a vaccine, as a prophylactic agent and as a component of combination antiviral therapy,” says the report, published online by the Journal of Infectious Diseases.
The study was done by scientists from the University of Hong Kong; Shantou University in Guangdong, China; St. Jude Children’s Research Hospital in Memphis, Tenn.; and the Center for Indonesian Veterinary Studies in Jakarta. Chung Lam-Cheung of the University of Hong Kong was the first author.
The researchers analyzed the genetic sequences of the M2 ion channel protein of 638 H5N1 viruses, including 599 from birds and 39 from humans. Most of the isolates came from Hong Kong, China, Vietnam, Thailand, and Indonesia, with a few from Cambodia, Malaysia, Japan, and Korea. The sequences were screened for four mutations predicted to confer amantadine resistance.
Tabular data in the report show that 92.6% (162 of 175) of the Vietnam isolates had resistance mutations, as did all the isolates from Thailand (58 of 58), Cambodia (9 of 9), and Malaysia (2 of 2). In contrast, only 13% (16 of 123) of the isolates from China and 6.3% (2 of 32) of those from Indonesia had such mutations. None of the eight isolates from Japan and Korea, collected from poultry in late 2003, showed resistance.
“Although amantadine-resistant H5N1 viruses are present in Asia, their distribution appears to be largely limited to Thailand, Vietnam, and Cambodia,” the report states. In an apparent reference to reports of amantadine use in poultry in China, the authors add, “That most H5N1 isolates from China and Indonesia are sensitive to amantadine is striking and perhaps surprising, in view of the reportedly widespread administration of amantadine to farmed poultry in some countries.”
Amantadine and rimantadine have been used in treating human flu for more than a decade. However, flu viruses can quickly become resistant to the drugs, because just one point mutation is required. Last January, the Centers for Disease Control and Prevention advised physicians to stop prescribing the drugs for the rest of the flu season because the predominant strain of influenza A had turned highly resistant to them. The resistance rate in the H3N2 strain had soared to 91%, compared with 11% the year before.
Cheung C-L, Rayner JM, Smith GJD, et al. Distribution of amantadine-resistant H5N1 avian influenza variants in Asia. J Infect Dis 2006 Jun 15;193 (early online publication) [Abstract]
There’s no reason why you can’t take combination antivirals. It would be even better if proper studies are done to determine dosage/ possible interactions, but in the absence of that, there is no scientific contraindication to taking both amantadine and tamiflu at the same time.
relenza and tamiflu is another combo that needs to be studid.
OK, so if I had Tamiflu, Relenza and Amantadine, I could take all three at the same time?
Watch Dog,
None of this counts as practicing medicine, but I’d be very careful when going on a pair. Even that hasn’t been studied for interaction and dosing. How would you know how much to take?
Hi everyone. There has been cases of resistance to Tamiflu including at least two cases during treatment of H5N1 in Vietnam: and historically resistance to amantidine and rimantadine. There are also some serious neurological side-effects listed for these treatments.
I don’t want to ‘rain on everyones parade’ but the two things that happen when a drug doesn’t work is 1) double the dose and 2) use it in combination with other drugs.
I have used this technique in treating animals as well and sometimes combination therapy works very effectively…
…I just think we might want to give these issues some thought and at the same time consider that if the pandemic begins in the near future, the new treatment regimes mean there will be very little avaliable for anyone other than front-line workers and politicians.
Is there an alternative treatment not involving antivirals that will not be avalilable anyway?
That’s why I am asking. I love the fact that some of the smartest people in the world are here on fluwiki.
“OK, so if I had Tamiflu, Relenza and Amantadine, I could take all three at the same time?”
No reason why not. Tamiflu and relenza belong to the same group of drugs but relenza only acts on the bronchial epithelium and is not well-absorbed, whereas tamiflu is absorbed from the stomach and acts on all systems except the brain. Using the 2 together would give you the benefit that relenza with its early availability (<30 min) locally will reduce total virus absorption into the body, assuming respiratory exposure, making it easier for the tamiflu to win the battle for the receptors. An early win for tamiflu means no virus in the central nervous system.
Amantadine complements all that by acting on a different mechanism of the virus. Even though the chance of resistance is higher, used in combination, there is less chance of virus ‘escape’ (ie insufficient antivirals killing viruses) and therefore less chance of resistance.
Side effects of these should not be cumulative (except maybe gastrointestinal upset) although as I said it would be better if we have exact studies of these combinations. But that is a luxury that we don’t have, and it’s not an unusual situation. Most drug combinations that people end up taking are not tested exactly as taken.
Watch Dog at 19:16 says
“OK, so if I had Tamiflu, Relenza and Amantadine, I could take all three at the same time?”
Courses of all three antivirals? You are both well off and well connected! Half your luck would do ME nicely, mate! I feel lucky to have aspirin in the apartment….
I will, therefore, shelter-in-place (SIP) very, very strictly, for one viral particle and I’m history!
Good luck, Watch Dog! You’ve prepped well, mate!
Nik-
No despair for you, old friend . . .
Thai food (lemongrass, galangal, et al), citrus fruit (including the peels), clove buds, garlic, eucalyptus leaves . . . the list is endless.
Eat, brew tea, make potpourri, burn as incense, use in a warming bath, et al.
Food is your best weapon-
Wouldn’t you be happier with 300 anti-virals? Go to the market or order online just about any aromatic spice or herb. Use them in rotating combination in foods, teas . . . be inventive.
Old thread - Closed to increase Forum speed.