Taribavirin

Drugbox
IUPAC_name = 1- [(2"R",3"R",4"S",5"S")- 3,4-dihydroxy-5- (hydroxymethyl)oxolan-2-yl] - 1,2,4-triazole-3-carboximidamide


width=134
CAS_number=119567-79-2
ATC_prefix=J05
ATC_suffix=AB04
PubChem=451448
DrugBank=none
C = 8 | H = 13 | N = 5 | O = 4
molecular_weight = 243.220 g/mol (279.681 g/mol for HCl salt)
synonyms = 1-(β-D-Ribofuranosyl)-
1,2,4-triazole-3-carboximide
bioavailability= 9%
metabolism = Metabolized to 5'phosphates, de-riboside, and deriboside carboxylic acid
elimination_half-life=12 days - Multiple Dose; 120-170 hours - Single Dose
excretion = 10% fecal, remainder in urine (30% unchanged, remainder metabolites)
pregnancy_category = X
legal_status = In Phase III drug trials
routes_of_administration= Oral capsule

Taribavirin (rINN; also known as viramidine, codenamed ICN 3142) is an antiviral drug in Phase III human trials, but not yet approved for pharmaceutical use. It is a prodrug of ribavirin, active against a number of DNA and RNA viruses. Taribavirin has better liver-targeting than ribavirin, and has a shorter life in the body due to less penetration and storage in red blood cells. It is expected eventually to be the drug of choice for viral hepatitis syndromes in which ribavirin is active. These include hepatitis C and perhaps also hepatitis B and yellow fever.

Taribavirin is as active against influenza as ribavirin in animal models, with slightly less toxicity, so it may also eventually replace ribavirin as an anti-influenza agent.

Taribavirin is being developed by Valeant Pharmaceuticals International, the parent company of Ribapharm, the company which first reported synthesis and testing of the drug in 1973. Valeant is testing the drug as a treatment for chronic hepatitis C.

Note on formulas: The carboxamidine group of this molecule is somewhat basic, and therefore this drug is also known and administered as the hydrochloride salt (with a corresponding .HCl chemical formula and different ChemID / PubChem number). At physiologic pH, the positive charge on the molecule from partial protonation of the carboximide group contributes to the relative slowness with which the drug crosses cell membranes (such as in red blood cells) until it has been metabolized into ribavirin. In the liver, however, the transformation from carboxamidine to carboxamide happens on first-pass metabolism and contributes to the higher levels of ribavirin found in liver cells and bile when viramidine is administered.

References

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# cite journal
last = Gish
first = Robert G.
year = 2006
month = January
title = Treating HCV with ribavirin analogues and ribavirin-like molecules
journal = Journal of Antimicrobial Chemotherapy
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issue = 1
pages = 8–13
pmid = 16293677
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# cite journal
last = Lin
first = Chin-Chung
authorlink =
coauthors = Kenneth Luu, David Lourenco, and Li-Tain Yeh
title = Pharmacokinetics and Metabolism of 14C Viramidine in Rats and Cynomolgus Monkeys
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# cite journal
last = Sidwell
first = RW
coauthors = Bailey KW, Wong MH, Barnard DL, Smee DF
year = 2005
month = October
title = In vitro and in vivo influenza virus-inhibitory effects of viramidine
journal = Antiviral Research
volume = 68
issue = 1
pages = 8–13
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# cite journal
last = Witkowski
first = J. T.
authorlink =
coauthors = Robins, R. K., Khare, G. P. et al
title = Synthesis and antiviral activity of 1,2,4-triazole-3-thiocarboxamide and 1,2,4-triazole-3-carboxamidine ribonucleosides
journal = Journal of Medicinal Chemistry
volume = 16
issue =
pages = 935–7
publisher =
date = 1973
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