Oseltamivir chemical structuresynthesis of tamiflu
Find information on thousands of medical conditions and prescription drugs.

Tamiflu

Oseltamivir (pronounced ah sell TAH mih veer) is an antiviral drug used in the treatment and prophylaxis of both influenza A and influenza B. Like zanamivir, oseltamivir is a neuraminidase inhibitor, acting as a transition-state analogue inhibitor of influenza neuraminidase and thereby preventing new viruses from emerging from infected cells. Oseltamivir was the first orally active neuraminidase inhibitor commercially developed. more...

Home
Diseases
Medicines
A
B
C
D
E
F
G
H
I
J
K
L
M
N
O
P
Q
R
S
T
Oxytetracycline
Phentermine
Tacrine
Tacrolimus
Tagamet
Talbutal
Talohexal
Talwin
Tambocor
Tamiflu
Tamoxifen
Tamsulosin
Tao
Tarka
Taurine
Taxol
Taxotere
Tazarotene
Tazobactam
Tazorac
Tegretol
Teicoplanin
Telmisartan
Temazepam
Temocillin
Temodar
Temodar
Temozolomide
Tenex
Teniposide
Tenoretic
Tenormin
Tenuate
Terazosin
Terbinafine
Terbutaline
Terconazole
Terfenadine
Teriparatide
Terlipressin
Tessalon
Testosterone
Tetrabenazine
Tetracaine
Tetracycline
Tetramethrin
Thalidomide
Theo-24
Theobid
Theochron
Theoclear
Theolair
Theophyl
Theophyl
Theostat 80
Theovent
Thiamine
Thiomersal
Thiopental sodium
Thioridazine
Thorazine
Thyroglobulin
Tiagabine
Tianeptine
Tiazac
Ticarcillin
Ticlopidine
Tikosyn
Tiletamine
Timolol
Timoptic
Tinidazole
Tioconazole
Tirapazamine
Tizanidine
TobraDex
Tobramycin
Tofranil
Tolazamide
Tolazoline
Tolbutamide
Tolcapone
Tolnaftate
Tolterodine
Tomoxetine
Topamax
Topicort
Topiramate
Tora
Toradol
Toremifene
Tracleer
Tramadol
Trandate
Tranexamic acid
Tranxene
Tranylcypromine
Trastuzumab
Trazodone
Trenbolone
Trental
Trest
Tretinoin
Triacetin
Triad
Triamcinolone
Triamcinolone hexacetonide
Triamterene
Triazolam
Triclabendazole
Triclosan
Tricor
Trifluoperazine
Trilafon
Trileptal
Trimetazidine
Trimethoprim
Trimipramine
Trimox
Triprolidine
Triptorelin
Tritec
Trizivir
Troglitazone
Tromantadine
Trovafloxacin
Tubocurarine chloride
Tussionex
Tylenol
Tyrosine
U
V
W
X
Y
Z

Oseltamivir is a prodrug (usually administered as phosphate); it is hydrolysed hepatically to the active metabolite, the free carboxylate of oseltamivir (GS4071).

Oseltamivir was developed by Gilead Sciences and is currently marketed by Hoffmann-La Roche (Roche) under the trade name TamifluĀ®.

With increasing fears about the potential for a new influenza pandemic, oseltamivir has received substantial media attention. Production capacity is limited, and governments are stockpiling the drug.

Technical information

Indications and dosage

Roche recommendations in the United States

Tamiflu is available from Roche in 75mg capsules and as a powder for aqueous suspension of 12 mg/mL. According to prescription information by Roche for the United States, Tamiflu usage is indicated for both the treatment and prophylaxis of influenza at the following dosages.

  • Tamiflu is indicated for the treatment of influenza in patients 1 year and older who have had symptoms for no more than two days. For influenza treatment, the standard dosage for patients 13 years and older is 75 mg twice daily for five days. Dosage for children is by weight.
  • Tamiflu is indicated for prophylaxis of influenza either during a community outbreak or following close contact with an infected individual. Standard dosage is 75 mg once daily for patients aged 13 and older, which has been shown to be safe and effective for up to six weeks. Safety and efficacy for prophylaxis has not been established for patients under 13 years old.

The above treatment regimes are based upon studies of normal human influenza.

Dosage for avian flu

Peter Hobby (of the World Health Organization) has suggested that Vietnam should investigate and test a higher dosage and longer treatment with Tamiflu for patients with avian influenza. Doctors in Vietnam concur, noting that

t least in some patients with influenza A (H5N1) virus infection, treatment with the recommended dose of oseltamivir incompletely suppresses viral replication. Besides allowing the infection to proceed, such incomplete suppression provides opportunities for drug resistance to develop. (de Jong et al. 2005)

Co-administration with probenecid

It has been suggested that co-administration of oseltamivir with another drug called probenecid could dramatically extend the world's limited supply of oseltamivir. Probenecid reduces excretion of oseltamivir's active metabolite. 500 mg of probenecid given every six hours doubles oseltamivir's maximum blood concentration and also doubles the time that oseltamivir stays in the blood, multiplying a patient's overall exposure to the drug 2.5-fold. Probenecid was used in similar fashion during World War II to extend limited supplies of penicillin. The evidence for this interaction comes from a 2002 study by Roche (Hill et al. 2002), but was publicized only in October 2005 by a doctor who had reviewed the data (Butler 2005).

Read more at Wikipedia.org


[List your site here Free!]


Roche halts Tamiflu supply to H.K. pharmacies
From Asian Economic News, 11/7/05

HONG KONG, Nov. 3 Kyodo

Flu treatment Tamiflu's Swiss maker Roche has stopped supplying the drug to Hong Kong pharmacies and private doctors to reserve world supply in case a flu pandemic strikes, the company said Thursday.

Roche Hong Kong spokeswoman Farrah Chan said in a statement the company notified doctors and drug stores of the cease of supply on Tuesday to ''reserve for the use at the time of the influenza season.''

Countries other than Hong Kong where supply of the drug was also halted include the United States, Finland, Canada and Denmark, the statement said. The company did not confirm if any other country has been licensed to produce the drug.

Demand for the drug is expected to significantly outweigh supply during a flu pandemic that could be caused by a mutation of the dangerous bird flu virus H5N1 strain, enabling it to jump from birds to humans on a mass scale.

Japan's Chugai Pharmaceutical Co., a member company of Roche, was licensed to produce Tamiflu.

Reports that Roche's Shanghai company in China may be licensed have yet to be confirmed.

Taiwan and Argentina, meanwhile, have said they developed a generic medicine with a function similar to Tamiflu and will use it if a pandemic hits whether Roche licenses it or not.

Hong Kong's health chief York Chow said Roche's decision is understandable and he vowed the supply in public hospitals in Hong Kong will not be affected.

''The public should realize that misuse of Tamiflu might cause drug resistance in the flu virus,'' he said, adding that the current 3.5 million capsules of Tamiflu in stock will be sufficient should there be a human flu pandemic because only seriously ill patients with complications would be given the drug.

The retail price of a 10-capsule box of the antiviral rose from around HK$180 (US$23) a few months ago to HK$600 shortly before the stock went out, despite a Roche promise not to raise prices.

Hong Kong Medical Association President Gabriel Choi said private doctors and hospitals are told that new orders of Tamiflu will not be available in the next 18 months.

However, government orders will continue to be filled, the pharmaceutical company said.

Hong Kong's stockpiling target is 20 million capsules by 2007, while the neighboring Chinese province Guangdong has 10,000 Tamiflu capsules in stock, in addition to other treatments such as Chinese herbal medicines.

The provincial health department said it will stock up on the antiviral in future if needs arise, meanwhile, they will strengthen monitoring and notification systems with Hong Kong and give early warnings to the territory if there are suspected cases of humans catching bird flu.

According to Roche, the greatest use of Tamiflu now is in Japan.

There were an estimated 16 million influenza infections in Japan over the past influenza season and about six million of those people took Tamiflu.

COPYRIGHT 2005 Kyodo News International, Inc.
COPYRIGHT 2005 Gale Group

Return to Tamiflu
Home Contact Resources Exchange Links ebay