Tamiflu – It kills rats, does it stop bird flu?

Roche Lab’s Tamiflu (Oseltamivir) is an anti-enzyme drug that’s being sold and sought widely in light of the much-fanned hue and cry over the potential flu.

Damn those birds (and call my broker)!

Tamiflu isn’t a new drug. It shows up in Roche’s roster back in 1999 – after they bought if from Gilead Pharmaceuticals, which designed it in 1996.

Tamiflu is intended for short-term treatment.

Vomiting and naseau were increased in young adults and elderly persons taking the drug – (independent of each other, apparently – vomiting rates increased ahead of naseau).

But there were no egregious effects on humans reported in the short-term drug trial.

From the label1:

Those events reported numerically more frequently in patients taking TAMIFLU compared with placebo were nausea, vomiting, bronchitis, insomnia and vertigo.”

The effects of the drug, in a short course in the small test sample, is to decrease the duration of the flu by a period of approximately 1-2 days, but not to prevent illness.

Will Tamiflu be effective against a new flu?

(“Is there a new flu,” is a separate question.)

Tamiflu is supposed to interfere with the activity of the neuraminidase enzyme, a protein which has been associated with flu viruses.

I don’t know enough about that to comment – maybe you do

  • Is this enzyme associated with other processes?
  • Is the drug absolutely specific to one enzyme?
  • Is it cross-reactive?
  • How does it affect immunity?
  • The drug doesn’t strengthen natural immunity – it disables a protein – so what else does it do?

Dead Meese Tell No Tales…

According to Roche, the manufacturer, we don’t know much about the drug, but we know that in animals, the drug comes through breast milk

and it did kill the baby rats in the study.

“The unpublished trial described by the FDA involved 7-day-old rats being fed a single dose of 1000 mg/kg of oseltamivir — about 250 times the dose recommended for children.”

The treatment was toxic, often killing the animals, and brain levels of the drug were 1500 times those of adult animals exposed to the same dose.”

It is hypothesized that an immature blood–brain barrier may cause the toxicity.”

Roche Laboratories Inc. is writing to inform you of new preclinical safety data that have implications for the use of Tamiflu® (oseltamivir phosphate) in very young children.

Tamiflu is indicated for the treatment of uncomplicated acute illness due to influenza infection in patients 1 year and older who have been symptomatic for no more than 2 days.

Tamiflu is also indicated for the prophylaxis of influenza in adult patients and adolescents 13 years and older.”

Tamiflu is not indicated for either treatment or prophylaxis of influenza in patients less than 1 year of age.”

Well, it’s probably fine. A fine, fine product.

After all, I wouldn’t want to jump to any conclusions, or cause a panic, just because I haven’t had time to learn all I can about the drug’s in vivo chemistry..

‘cause hey – neither has the manufacturer…!

From the Tamiflu label2:

Key Phrases: “Has Not Been Established,” “Has Not Been Studied” and “Is Not Known

  • TAMIFLU is indicated for the treatment of uncomplicated acute illness due to influenza infection in patients older than 1 year of age who have been symptomatic for no more than 2 days.
  • Efficacy of TAMIFLU in patients who begin treatment after 40 hours of symptoms has not been established.
  • Efficacy of TAMIFLU in the treatment of subjects with chronic cardiac disease and/or respiratory disease has not been established.
  • Efficacy of TAMIFLU in the treatment of subjects with chronic cardiac disease and/or respiratory disease has not been established. No difference in the incidence of complications was observed between the treatment and placebo groups in this population.
  • No information is available regarding treatment of influenza in patients with any medical condition sufficiently severe or unstable to be considered at imminent risk of requiring hospitalization.
  • Safety and efficacy of repeated treatment or prophylaxis courses have not been studied.
  • Efficacy of TAMIFLU for treatment or prophylaxis has not been established in immunocompromised patients.
  • Serious bacterial infections may begin with influenza-like symptoms or may coexist with or occur as complications during the course of influenza. TAMIFLU has not been shown to prevent such complications.
  • Hepatic Impairment: The safety and pharmacokinetics in patients with hepatic impairment have not been evaluated.
  • Because animal reproductive studies may not be predictive of human response and there are no adequate and well-controlled studies in pregnant women,
  • TAMIFLU should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.
  • Nursing Mothers: In lactating rats, oseltamivir and oseltamivir carboxylate are excreted in the milk. It is not known whether
    oseltamivir or oseltamivir carboxylate is excreted in human milk.

  • TAMIFLU should, therefore, be used only if the potential benefit for the lactating mother justifies the potential risk to the breast-fed infant.

Only if the potential benefit justifies the potential risk to the fetus?”

How scientific!!

How Exciting!!

Notes and References:

Hoffman/La Roche Tamiflu Info Page

1 FDA/Roche Tamiflu PDF

2 Canadian Medical Journal – Oseltamivir (Tamiflu) unsafe in infants under 1 year old

3 From Roche Labs – Dear Doctor letter

Liam