VALACYCLOVIR
Drugs in Pregnancy and Lactation.
Welcome to Pregnancy Without PoundsYou absolutely DO NOT have to pack on extra pregnancy weight.
Get a FREE subscription to my Pregnancy Exercise, Diet and Beauty Tips Newsletter sent to you each week.Sign In! |
Name: VALACYCLOVIR
Class: Antiviral
Risk Factor: BM
Fetal Risk Summary
Valacyclovir is biotransformed to acyclovir and L-valine by first-pass intestinal and/or hepatic metabolism. The drug is active against herpes simplex virus types 1 and 2 and varicella-zoster virus. It is used in the treatment of herpes zoster (shingles) and recurrent genital herpes simplex.
Reproduction studies were conducted in rats and rabbits during organogenesis with doses of 400 mg/kg, producing concentrations 10 and 7 times human plasma levels, respectively (1). No teratogenic effects were observed with these doses.
The active metabolite, acyclovir, readily crosses the human placenta (see Acyclovir). An abstract and study, both published in 1998, compared the pharmacokinetics of valacyclovir and acyclovir in late pregnancy (2,3). Acyclovir accumulated in the amniotic fluid but not in the fetus. The mean maternal/umbilical vein plasma ratio at delivery was 1.7.
The Valacyclovir Pregnancy Registry listed 157 prospective reports of women exposed to the oral antiviral drug during gestation covering the period from January 1, 1995, through April 30, 1999 (4). Of the total, 47 (30%) pregnancies were lost to follow-up. Among the 111 (1 set of twins) known outcomes, 29 had earliest exposure in the 1st trimester and their outcomes were 5 spontaneous abortions, 2 induced abortions, 1 infant with a birth defect (talipes), and 21 infants (including the twins) without birth defects. When the earliest exposure was in the 2nd trimester, 31 pregnancies were enrolled and their outcomes were 2 stillbirths, 2 infants with birth defects (fingers and toes fused—extensive webbing; small cleft in front gum), and 27 without birth defects. In the remaining 51, the earliest exposure occurred in the 3rd trimester, with 1 infant with a dermal sinus tract and 50 without birth defects (4).
A total of 34 retrospective reports of valacyclovir exposure during pregnancy were submitted to the Registry (4). Two of the exposures occurred during an unspecified gestational time and both resulted in live births without defects. In 14 pregnancies, the earliest exposure occurred during the 1st trimester. The outcomes of these pregnancies were three spontaneous losses, eight induced abortions, and three infants without birth defects. For the pregnancies whose earliest exposure was in the 2nd trimester (N=4) or 3rd trimester (N=14), there was 1 birth defect (2nd trimester exposure) and 17 infants without defects. (See the statement below that is required by the registry for use of these data.)
A 1999 case report described a woman at 20 weeks' gestation who had a generalized herpes simplex virus infection that was treated with IV acyclovir for about 2 weeks followed by valacyclovir for the remainder of the pregnancy (5). She delivered a full-term, healthy female infant who was treated prophylactically with oral acyclovir for 1 month. No abnormalities were detected during a neurologic examination at 8 months of age.
Except for the above data, no other reports describing the use of valacyclovir during human pregnancy have been located. However, a large number of studies have reported the use of the active metabolite, acyclovir, during human pregnancy (see also Acyclovir). Based on the combined data, there does not appear to be any major risk to the human fetus from valacyclovir or acyclovir. Long-term follow-up of children exposed in utero to these agents is warranted.
Required statement: The cases accumulated represent a sample of insufficient size for reaching reliable and definitive conclusions regarding the risk of valacyclovir to pregnant women and developing fetuses. In addition, underreporting, differential reporting, and losses to follow-up are potential limitations of the registry. Despite these limitations, the registry was intended to supplement animal toxicology studies and assist clinicians in weighing the risks and benefits of treatment for individual patients and circumstances.
Breast Feeding Summary
No reports have been located that described the use of valacyclovir during human lactation. Valacyclovir is rapidly and nearly completely converted to acyclovir and the amino acid, L-valine. Acyclovir is concentrated in human milk with milk:plasma ratios in the 3–4 range (see Acyclovir). Because acyclovir has been used to treat herpesvirus infections in the neonate, and because of the lack of adverse effects in reported cases in which acyclovir was used during breast feeding, the American Academy of Pediatrics considers acyclovir to be compatible with breast feeding (see Acyclovir) (6). Based on this information, valacyclovir should also be compatible with breast feeding.
References
- Product information. Valtrex. Glaxo Wellcome, 1997.
- Kimberlin DF, Weller S, Andrews WW, Hauth JC, Whitley RJ, Lakeman F, Miller G, Lee C, Goldenberg RL. Valaciclovir pharmacokinetics in late pregnancy (abstract). Am J Obstet Gynecol 1998;178:S12.
- Kimberlin DF, Weller S, Whitley RJ, Andrews WW, Hauth JC, Lakeman F, Miller G. Pharmacokinetics of oral valacyclovir and acyclovir in late pregnancy. Am J Obstet Gynecol 1998;179:846–51.
- Acyclovir Pregnancy Registry and Valacyclovir Pregnancy Registry. Final study report. 1 June 1984 through 30 April 1999. Glaxo Wellcome, 1999.
- Anderson R, Lundqvist A, Bergstrom T. Successful treatment of generalized primary herpes simplex type 2 infection during pregnancy. Scand J Infect Dis 1999;31:201–2.
- Committee on Drugs. American Academy of Pediatrics. The transfer of drugs and other chemicals into human milk. Pediatrics 1994;93:137–50.
Q&A about Valacyclovir
Valacyclovir, for herpes zoster, should actually be taken within 48 hours of the onset of a rash to be most effective, though the clinical studies performed started treatment within 72 hours (*info on the package insert)
My girlfriend has Genital Herpes HSV-I, but rarely has outbreaks. We are going to use Valacyclovir as a prophylaxis and of course a condom; however, I would like to have an antiviral gel or foam to cover the areas not covered by the condom. You guys have any recommendations?
http://www.news-medical.net/?id=7980
"Mount Sinai School of Medicine researchers demonstrated that a gel applied in the vagina provides protection from both the human immunodeficiency virus (HIV) and the herpes simplex Virus. The study, presented at the 12th Conference on Retroviruses and Opportunistic Infections, is the first to show that a gel can retain anti-viral activity within the human vagina"