3584 Valaciclovir Valaciclovir (INN) or valacyclovir (USAN) is an antiviral drug used in the management of herpes simplex and herpes zoster (shingles). It is a prodrug, being converted in vivo to aciclovir. It is marketed by GlaxoSmithKline under the trade name Valtrex or Zelitrex. [Wikipedia] 124832-26-4 60773 C13H20N6O4 324.154600 The blue, film-coated caplets are printed with edible white ink. 3.55e+00 g/L After oral administration, valaciclovir hydrochloride is rapidly absorbed from the gastrointestinal tract. The absolute bioavailability of acyclovir after administration of valaciclovir is 54.5% &plusmn; 9.1%. Valaciclovir is phosphorylated by viral thymidine kinase to acyclovir triphosphate (the active metabolite) which then inhibits herpes viral DNA replication by competitive inhibition of viral DNA polymerase, and by incorporation into and termination of the growing viral DNA chain. When used as a substrate for viral DNA polymerase, acyclovir triphosphate competitively inhibits dATP leading to the formation of 'faulty' DNA. This is where acyclovir triphosphate is incorporated into the DNA strand replacing many of the adenosine bases. This results in the prevention of DNA synthesis, as phosphodiester bridges can longer to be built, destabilizing the strand. Valaciclovir is rapidly and almost entirely (~99%) converted to the active compound, acyclovir, and L-valine by first-pass intestinal and hepatic metabolism by enzymatic hydrolysis. Neither valaciclovir nor acyclovir is metabolized by cytochrome P450 enzymes. Acyclovir is converted to a small extent to inactive metabolites by aldehyde oxidase and by alcohol and aldehyde dehydrogenase. Plasma concentrations of unconverted valacyclovir are low and transient, generally becoming non-quantifiable by 3 hours after administration. Peak plasma valacyclovir concentrations are generally less than 0.5 mcg/mL at all doses. After single-dose administration of 1 gram of VALTREX, average plasma valacyclovir concentrations observed were 0.5, 0.4, and 0.8 mcg/mL in patients with hepatic dysfunction, renal insufficiency, and in healthy volunteers who received concomitant cimetidine and probenecid, respectively. Route of Elimination: Acyclovir accounted for 89% of the radioactivity excreted in the urine. Half Life: 2.5-3.3 hours No indication of carcinogenicity to humans (not listed by IARC). For the treatment or suppression of cold sores (herpes labialis), herpes zoster (shingles), genital herpes in immunocompetent individuals, and recurrent genital herpes in HIV-infected individuals. Cold Sores (Herpes Labialis): VALTREX is indicated for treatment of cold sores (herpes labialis). The efficacy of VALTREX initiated after the development of clinical signs of a cold sore (e.g., papule, vesicle, or ulcer) has not been established. Genital Herpes: Initial Episode: VALTREX is indicated for treatment of the initial episode of genital herpes in immunocompetent adults. The efficacy of treatment with VALTREX when initiated more than 72 hours after the onset of signs and symptoms has not been established. General: Facial edema, hypertension, tachycardia. Allergic:Acute hypersensitivity reactions including anaphylaxis, angioedema, dyspnea, pruritus, rash, and urticaria. CNS Symptoms: Aggressive behavior; agitation; ataxia; coma; confusion; decreased consciousness; dysarthria; encephalopathy; mania; and psychosis, including auditory and visual hallucinations, seizures, tremors. Eye: Visual abnormalities. Gastrointestinal: Diarrhea. Hepatobiliary Tract and Pancreas: Liver enzyme abnormalities, hepatitis. Renal: Renal failure, renal pain (may be associated with renal failure). Hematologic: Thrombocytopenia, aplastic anemia, leukocytoclastic vasculitis, TTP/HUS. Skin: Erythema multiforme, rashes including photosensitivity, alopecia. Adverse effects of overexposure might include headache and nausea. In the event of acute renal failure and anuria, the patient may benefit from hemodialysis until renal function is restored. (L1712) 2009-07-30T17:59:13Z 2026-03-31T17:38:51Z Valaciclovir C07184 35854 Valaciclovir DB00577 TXC true CC(C)[C@H](N)C(=O)OCCOCN1C=NC2=C1NC(N)=NC2=O C13H20N6O4 InChI=1S/C13H20N6O4/c1-7(2)8(14)12(21)23-4-3-22-6-19-5-16-9-10(19)17-13(15)18-11(9)20/h5,7-8H,3-4,6,14H2,1-2H3,(H3,15,17,18,20)/t8-/m0/s1 HDOVUKNUBWVHOX-QMMMGPOBSA-N 324.3357 324.154603158 Exogenous Solid -0.3 HMDB14716 CHEMBL1349 54770 <p>Marina Etinger, &#8220;Synthesis and purification of valacyclovir.&#8221; U.S. Patent US20030153757, issued August 14, 2003.</p> CHEM002535 DTXSID1023732 2-[(2-amino-6-oxo-6,9-dihydro-3H-purin-9-yl)methoxy]ethyl (2S)-2-amino-3-methylbutanoate