Oseltamivir Risk Summary

Risk Factor: CM
Class: Anti-infectives / Antivirals

Fetal Risk Summary

Oseltamivir is an ethyl ester prodrug that is metabolized primarily in the liver by esterases to oseltamivir carboxylate, the active agent. The drug is active against influenza viruses, types A and B, and is given orally for the treatment of uncomplicated acute illness due to influenza infection.



In reproduction studies, doses up to approximately 100 times the human systemic exposure based on AUC (0 to 24 hours) of oseltamivir carboxylate (HSE) had no effects on fertility or mating performance in male and female rats, or on embryo-fetal development (1). Similarly, doses in rabbits up to 50 times the HSE also had no effect on embryo-fetal development (1). In both species, fetal exposure to the antiviral agent was documented. Although a dose-dependent increase in the incidence rates of skeletal abnormalities and variants were observed in both species, the individual incidence rate of each defect remained within the expected background rates of occurrence (1).

It is not known if oseltamivir or oseltamivir carboxylate cross the placenta to the human fetus. The molecular weight (about 312 for the free base of oseltamivir) is low enough that transfer to the fetus should be expected.

No reports describing the use of oseltamivir during human pregnancy have been located. The lack of embryo and fetal toxicity in two animal species is reassuring, but an assessment of the risk this antiviral agent presents to a human embryo or fetus cannot be determined.

Breast Feeding Summary

No reports describing the use of oseltamivir during human lactation have been located. In lactating rats, both oseltamivir and oseltamivir carboxylate are excreted into milk (1). Because the molecular weight of oseltamivir (about 312 for the free base) is low enough, excretion into breast milk should be expected. The effects of this exposure on a nursing infant are unknown.

References

  1. Product information. Tamiflu. Roche Laboratories, 2000.

Questions and Answers

What is Oseltamivir Phosphate?, * Plz list Sources*

~What is Oseltamivir Phosphate?

~ Where is it found/ used ?

~How it works

~ Effects on Humans

~ Formula (if there is one )

FYI: this is not my homework ~ i read it somewher and i jst want to knw wat it is and info about it
so plz dont waste ur or mi time saying i dont knw or do it urself
also plz dont copy others answers cuz i have no problem reporting you or answering the question to get 2 useless points ... Thnks

an oral anti-viral drug for the treatment of uncomplicated influenza in patients one year and older

Whether Oseltamivir is a Beta lactam based or ciproflaxocin based or streptomycin based??? ?,

How many times are you going to ask this question (the answer is 5).

None of the above. It's an antiviral.

Do you keep a secret a supply of oseltamivir (Tamiflu)?, for an avian influenza epidemic?

No.

Why stockpile an expensive med that isn't assured to work....

Can i use Central Tamiflu - Oseltamivir Phosphate to make muscles faster ??? and are there any side effects ??,

You want to use an antiviral medicine to make your muscles larger? That is a waste of good medicine. Save it for the flu.

Is Tamiflu (oseltamivir phosphate) available in either Shot or IV form?, We have a puppy who has Parvovirus (a deadly virus for puppies), I have found online that, dispite the fact it is originally intended to treet humans for flu/birdflu symptoms, Tamiflu is nearly 100% effective in curing Parvo in dogs too.

The problem is our poor puppy, Cooper, is so sick he is unable to hold down hardly any food/water without puking it up.

My question is, is there a version of this medication (Tamiflu) that is either in Shot format, or something that could be given in an IV to our puppy.

Thanks in advance for your help

Please take your dog to the vet, it is probably dehydrated from vomiting/no eating or drinking and he could probably do with some fluids. The vet will also tell you about the possibility of using tamiflu, although if he's been sick more than two days it wont do any good, Tamiflu is given if you have noticed symptoms for no more than 2 days.
Amanda RN

oseltamivir phosphate,SOR?,

It is a very tough question you asked my dear friend and for this reason i think no one gave any answer yet. So i suggest you to put your question in google or yahoo search engine and you will get many links for your answer. Try the followings :

Need to find a Viral Genetics Lab in Arlington, Texas... in need of alot of help?, I'm a student getting involved with the health clinical co-op program, in which i am required to get a job at a health facility. I've got an affinity for viral structure and genetics (and i even understand the properties and synthesis of oseltamivir and zanamivir!), but i cant find a research center near to me. I want this more than life itself, so please can you help? I've tried all the search engines and no luck... i need to find a center soon, so no wise-cracks please! Thanks to anyone who tries.
Ro
p.s. Orthomyxoviridae family is the coolest!

i cannot help you as far as clinical work, however, i hate to differ with you...
Flaviviridae family is the coolest! very diverse!
and HCV to me is the WORST! (i know because i had it!)

what's "drug-enzyme binding constant" ??, i have a work to do for Drug Design, about oseltamivir (Tamiflu), and one of the questions is about the drug-enzyme binding constant. but i have no idea what it is :|

obviously the drug has to be acting upon the enzyme..
the drug enzyme binding constant is a value whihc expresses the strength of bond between the drug and the enzyme...this gives potency of drug.
it is very useful in comparing the drug with standards or prototypes and their available drug enzyme binding constant.
also simply called dissociation constant....yes thats the more common word used

Can someone summarize this article for me?? plz?, here it is...

Tamiflu no longer works for dominant flu strain
U.S. health officials say almost 100% of the type A H1N1 strain showed resistance to the leading antiviral drug. So far, the influenza season has been mild.
By Mary Engel
February 4, 2009
A milder than usual U.S. flu season is masking a growing concern about widespread resistance to the antiviral drug Tamiflu and what that means for the nation's preparedness in case of a dangerous pandemic flu.

Tamiflu, the most commonly used influenza antiviral and the mainstay of the federal government's emergency drug stockpile, no longer works for the dominant flu strain circulating in much of the country, government officials said Tuesday.

Booster Shots: The Times' health blogOf samples tested since October, almost 100% of the strain -- known as type A H1N1 -- showed resistance to Tamiflu.

In response, the Centers for Disease Control and Prevention issued new guidelines to physicians in December. Doctors were told to substitute an alternative antiviral, Relenza, for Tamiflu, or to combine Tamiflu with an older antiviral, rimantadine, if the H1N1 virus was the main strain circulating in their communities.

Each flu season, several types of flu viruses circulate, and various ones can dominate in different regions and times. Only the H1N1 virus is showing signs of Tamiflu resistance, CDC officials said, speaking at an influenza conference in Washington. Other flu viruses currently circulating are not Tamiflu-resistant.

Each year, the three most prominent flu strains -- two type A's and one type B -- are chosen for the creation of the flu vaccine. Unlike last year, both of the A viruses matched this year's vaccine, although the B did not, officials said.

Public health experts recommend flu shots as the best way to avoid the virus.

Health officials have long urged constraint in using antivirals out of fear that, as with antibiotics, misuse could lead flu viruses to develop a resistance, rendering the drug ineffective when it was truly needed.

Tamiflu, which is known generically as oseltamivir, and Relenza, or zanamivir, came on the market 10 years ago. They were hailed as being more effective at treating the flu and having fewer side effects than the older antivirals rimantadine and amantadine. They were also lauded as being much less prone to develop resistance.

Tamiflu and Relenza have been stockpiled by the federal government for treating the public in case of the emergence of a dangerous pandemic flu. Four times as many Tamiflu doses have been stockpiled as Relenza doses.

Some microbiologists have argued that Tamiflu is more likely to develop resistance than Relenza. Therefore, they say, Relenza should make up at least 50% of the stockpiled antivirals.

"There have been people, and I'm one of them, that have suggested that there be more of an equal stockpiling of oseltamivir and zanamivir," said Dr. Anne Moscona, a pediatrician and professor of microbiology and immunology at New York-Presbyterian Hospital/Weill Cornell Medical Center.

Both drugs reduce the replication of influenza viruses by blocking an enzyme called neuraminidase. To do so, they slip into a pocket in the enzyme. The pocket has to change shape to accommodate Tamiflu, but not for Relenza. If a mutation in the virus stops the pocket from changing shape, Tamiflu can no longer slip in to do its work, Moscona said.

Tamiflu became the more popular drug because it can be taken orally in pill or liquid form, whereas Relenza must be inhaled and can't be used by young children or the elderly.

What mystifies infectious disease experts and microbiologists is that the Tamiflu-resistant strain now circulating appears to be a mutation that spread naturally, not as a response to antiviral use.

"We don't think it's due to overuse," said Dr. Anthony Fiore, a CDC epidemiologist. "There's not as large amount of use of oseltamivir as there might be with antibiotics."

Influenza viruses are RNA-based, which are error-prone when replicating. This means they change rapidly, Fiore said. If a change occurs that confers an advantage of some sort, then it's likely to be passed on.

Viruses also swap genes among themselves, and one fear is that the resistance mutation will be passed on to other flu viruses, including the deadly H5N1 bird flu circulating in Asia.

For now, H5N1 responds to Tamiflu, although it must be administered early. The virus is more than 60% fatal in humans.

Why don't you read it and summarize it? American schooling is becoming a joke. Kids are becoming lazier and lazier and then they go to college and it's a major wake-up call.

If you really want someone to summarize it for you, use Microsoft Word auto-summarize. It highlights what it sees as the most important information.

Opinions. (Patient readers only.) If you don't want to read the article go away.?, A potential hope for parvo found. Pls click and read before giving me your opinions on whether you think it's a good step towards an actual cure.

Continue reading here: Methionine: Benefits, Side Effects, Dosage, and Interactions

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