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AciclovirSystematic (IUPAC) name2-amino-9-((2-hydroxyethoxy)methyl)-1H-purin-6(9H)-oneIdentifiersCAS number59277-89-3ATC codeJ05AB01 D06BB03 S01AD03PubChem2022DrugBankAPRD00567ChemSpider1945Chemical dataFormulaC8H11N5O3 Mol. mass225.21 g/molSynonymsacycloguanosinePhysical dataMelt. point256.5 °C (494 °F)Pharmacokinetic dataBioavailability10–20% (oral)Protein binding9–33%MetabolismViral thymidine kinaseHalf life2.2–20 hoursExcretionRenalTherapeutic considerationsPregnancy cat.B3 (Au), B (U.S.)Legal statusunscheduled/S4 (Au), POM (UK)RoutesIntravenous, oral, topicalAciclovir (INN) (pronounced /eɪˈsaɪkloʊvɪr/) or acyclovir (USAN, former BAN), chemical name acycloguanosine, is a guanosine analogue antiviral drug, marketed under trade names such as Cyclovir, Herpex, Acivir, Zovirax and Zovir (GSK). One of the most commonly-used antiviral drugs, it is primarily used for the treatment of herpes simplex virus infections, as well as in the treatment of herpes zoster (shingles).Aciclovir was seen as the start of a new era in antiviral therapy, as it is extremely selective and low in cytotoxicity. Pharmacologist Gertrude B. Elion was awarded the 1988 Nobel Prize in Medicine, partly for the development of aciclovir.// Pharmacology Mechanism of actionAciclovir differs from previous nucleoside analogues in that it contains only a partial nucleoside structure: the sugar ring is replaced by an open-chain structure. It is selectively converted into acyclo-guanosine monophosphate (acyclo-GMP) by viral thymidine kinase, which is far more effective (3000 times) in phosphorylation than cellular thymidine kinase. Subsequently, the monophosphate form is further phosphorylated into the active triphosphate form, acyclo-guanosine triphosphate (acyclo-GTP), by cellular kinases. Acyclo-GTP is a very potent inhibitor of viral DNA polymerase; it has approximately 100 times greater affinity for viral than cellular polymerase. As a substrate, acyclo-GMP is incorporated into viral DNA, resulting in chain termination. It has also been shown that viral enzymes cannot remove acyclo-GMP from the chain, which results in inhibition of further activity of DNA polymerase. Acyclo-GTP is fairly rapidly metabolised within the cell, possibly by cellular phosphatases.In sum, aciclovir can be considered a prodrug: it is administered in an inactive (or less active) form and is metabolised into a more active species after administration. MicrobiologyAciclovir is active against most species in the herpesvirus family. In descending order of activity:Herpes simplex virus type I (HSV-1)Herpes simplex virus type II (HSV-2)Varicella zoster virus (VZV)Epstein-Barr virus (EBV)Cytomegalovirus (CMV) -- least activityActivity is predominantly against HSV, and to a lesser extent VZV. It is only of limited efficacy against EBV and CMV. It is inactive against latent viruses in nerve ganglia.To date, resistance to aciclovir has not been clinically significant. Mechanisms of resistance in HSV include deficient viral thymidine kinase; and mutations to viral thymidine kinase and/or DNA polymerase, altering substrate sensitivity. PharmacokineticsAciclovir is poorly water soluble and has poor oral bioavailability (10–20%), hence intravenous administration is necessary if high concentrations are required. When orally administered, peak plasma concentration occurs after 1–2 hours. Aciclovir has a high distribution rate, only 30% is protein-bound in plasma. The elimination half-life of aciclovir is approximately 3 hours. It is renally excreted, partly by glomerular filtration and partly by tubular secretion.The poor oral bioavailability may also be improved by administering Valaciclovir, which has an oral bioavailability of about 55%. Valaciclovir is then converted to Aciclovir by esterases via hepatic first-pass metabolism. Clinical use IndicationsAciclovir is indicated for the treatment of HSV and VZV infections, including:Genital herpes simplex (treatment and prophylaxis)Herpes simplex labialis (cold sores)Herpes zoster (shingles)Acute chickenpox in immunocompromised patientsHerpes simplex encephalitisAcute mucocutaneous HSV infections in immunocompromised patientsHerpes simplex keratitis (ocular herpes)Herpes simplex blepharitis (not to be mistaken with ocular herpes)Bell's PalsyIt has been claimed that the evidence for the effectiveness of topically applied cream for recurrent labial outbreaks is weak. An earlier review of scientific literature showed that there is some effect in reducing the number and duration of lesions if aciclovir is applied at an early stage of an outbreak. However, it was concluded that oral therapy for episodes is inappropriate for most non-immunocompromised patients based on costs and benefits, presumably in countries where aciclovir is only available on prescription. It was concluded that there is evidence for an oral prophylactic role in preventing recurrences. Dosage formsAciclovir is commonly marketed as tablets (200mg, 400mg, 800mg and 1 gram), topical cream (5%), intravenous injection (25 mg/mL) and ophthalmic ointment (3%). Cream preparations are used primarily for labial herpes simplex. The intravenous injection is used when high concentrations of aciclovir are required. The ophthalmic ointment preparation is only used for herpes simplex keratitis. Adverse effects Systemic therapyCommon adverse drug reactions (≥1% of patients) associated with systemic acyclovir therapy (oral or IV) include: nausea, vomiting, diarrhea and/or headache. In high doses, hallucinations have been reported. Infrequent adverse effects (0.1–1% of patients) include: agitation, vertigo, confusion, dizziness, oedema, arthralgia, sore throat, constipation, abdominal pain, rash and/or weakness. Rare adverse effects (<0.1% of patients) include: coma, seizures, neutropenia, leukopenia, crystalluria, anorexia, fatigue, hepatitis, Stevens-Johnson syndrome, toxic epidermal necrolysis and/or anaphylaxis.Additional common adverse effects, when acyclovir is administered IV, include encephalopathy (1% of patients) and injection site reactions. The injection formulation is alkaline (pH 11), and extravasation may cause local tissue pain and irritation. Renal impairment has been reported when acyclovir is given in large, fast doses intravenously, due to the crystallisation of acyclovir in the kidneys. Topical therapyAcyclovir topical cream is commonly associated (≥1% of patients) with: dry or flaking skin or transient stinging/burning sensations. Infrequent adverse effects include erythema or itch.When applied to the eye, acyclovir is commonly associated (≥1% of patients) with transient mild stinging. Infrequently (0.1–1% of patients), ophthalmic aciclovir is associated with superficial punctate keratitis or allergic reactions. ToxicitySince acyclovir can also be incorporated into cellular DNA, it is a chromosome mutagen, therefore, its use should be avoided during pregnancy. However it has not been shown to cause any teratogenic or carcinogenic effects. The acute toxicity (LD50) of aciclovir when given orally is greater than 1 g/kg, due to its low oral bioavailability. Footnotes^ O'Brien JJ, Campoli-Richards DM. Aciclovir. An updated review of its antiviral activity, pharmacokinetic properties and therapeutic efficacy. Drugs 1989;37(3):233-309. PMID 2653790^ Sweetman S, editor. Martindale: The complete drug reference. 34th ed. London: Pharmaceutical Press; 2004. ISBN 0-85369-550-4^ a b c d e Rossi S, editor. Australian Medicines Handbook 2006. Adelaide: Australian Medicines Handbook; 2006. ISBN 0-9757919-2-3^ Graham Worrall (6 Jul 1996). "Evidence for efficacy of topical aciclovir in recurrent herpes labialis is weak". BMJ 313: 46. http://www.bmj.com/cgi/content/full/313/7048/46/a.  - Letter^ Graham Worrall (6 Jan 1996). "Acyclovir in recurrent herpes labialis". BMJ 312: 6. PMID 8555890. http://www.bmj.com/cgi/content/full/312/7022/6.  - Editorial Further readingHarvey Stewart C. in Remington’s Pharmaceutical Sciences 18th edition: (ed. Gennard, Alfonso R.) Mack Publishing Company, 1990. ISBN 0-912734-04-3.Huovinen P., Valtonen V. in Kliininen Farmakologia (ed. Neuvonen et al.). Kandidaattikustannus Oy, 1994. ISBN 951-8951-09-8.Périgaud C., Gosselin G., Imbach J. -L.: Nucleoside analogues as chemotherapeutic agents: a review. Nucleosides and nucleotides 1992; 11(2-4)Rang H.P., Dale M.M., Ritter J.M.: Pharmacology, 3rd edition. Pearson Professional Ltd, 1995. 2003 (5th) edition ISBN 0-443-07145-4; 2001 (4th) edition ISBN 0-443-06574-8; 1990 edition ISBN 0-443-03407-9. External LinksZovirax Official Website See alsoValaciclovirv • d • eAntibiotics and chemotherapeutics for dermatological use (D06)AntibioticsTetracycline and derivativesDemeclocycline · Chlortetracycline · Oxytetracycline · TetracyclineOthersAmphenicol: ChloramphenicolAminoglycosides: Neomycin · Gentamicin · AmikacinQuinolone: NadifloxacinStreptogramin: VirginiamycinRifamycin: Rifaximinother: Fusidic acid · Bacitracin · Tyrothricin · MupirocinChemotherapeuticsSulfonamidesSilver sulfadiazine · Sulfathiazole · Mafenide · Sulfamethizole · Sulfanilamide · SulfamerazineAntiviralsIdoxuridine · Tromantadine · Aciclovir · Podophyllotoxin · Inosine · Penciclovir · Lysozyme · Ibacitabine · Edoxudine · Imiquimod · DocosanolOtherMetronidazolev • d • eDNA virus Antivirals (primarily J05, also S01AD and D06BB)Baltimore IHerpesvirusDNA synthesisinhibitorTK activatedpurine analogue (guanine) (Aciclovir #, Famciclovir, Ganciclovir, Penciclovir, Valaciclovir, Valganciclovir) · Vidarabine pyrimidine analogue (uridine) (Idoxuridine, Trifluridine) · BrivudineNot TK activatedFoscarnetOtherDocosanol · early protein (Fomivirsen) · TromantadineHPV/MCImiquimod · Podophyllotoxi

... ed in alcuni casi risparmierete un sacco di soldi. Read moreOh dear, poor The Al Gore. They include acyclovir (Zovirax), valacyclovir (Valtrex), famciclovir (Famvir).During the past 15 years, scientists have occasionally reported that people with HIV t..Viral illnesses differ from bacterial infections in that viruses are not living organisms, but rather take over living cells and reproduce themselves, often at the expense of the host cell. His blog for An Inconvenient Truth is now selling Viagra, Valium, Zovirax and Xanax.. Acyclovir is an antiviral drug which acts against the Herpes.non fermatevi al primo consigliato dal medico, ma chiedete anche in più farmacia il farmaco generico contenente lo stesso principio attivo. The Nobel Prize Laureate, Internet inventor and husband of Tipper has had his website hacked.The major drugs developed to work against herpes simplex virus (HSV) are antiviral agents called nucleosides and nucleotide analogues, which block viral reproduction.A team of researchers has identified how the anti-herpes drug acyclovir (Zovirax) limits HIV replication in people coinfected with herpes simplex virus (HSV), according to a report published in the September 11 issue of Cell

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