edited_Iturbe_edit.qxp 4/2/09 11:50 am Page 69
Treatment of Varicella Zoster Virus Infection
• patients with serious clinical forms, such as encephalitis, of infections
Table 3: Antiviral Therapy of Herpes Zoster from
by either virus; and
Pregnancy to Adults
• patients with serious complications of the VZ virus (see Table 1).
Pregnancy Either topical or systemic antiviral therapy not recommended
Children Aciclovir 500mg/m
2
or 10mg/kg every 8 hours IV,
The dosages of antiviral agents (in particular acyclovir) used in children
7–10 days
are indicated in Table 2. The dosages differ depending on whether
Adults Immunocompetent Immunocompromised
they refer to children or adults with or without immunocompromise.
Aciclovir Aciclovir
The age threshold for adulthood in this setting is considered to be 5x800mg/day po, 7 days 500mg/m
2
or 10mg/kg every 8
above 12 years of age. The dosage for children between three months
hours IV, 7–10 days
and 12 years of age is usually calculated on the basis of body surface
5x800mg/day po, 7–10 days
area or weight (see Table 2). In those patients with altered renal
(without visceral involvement,
moderate immunocompromise)
function, appropriate modifications to the dosage in accordance with
Valaciclovir Valaciclovir
their creatinine clearance are required.
3x1,000mg/day po, 7 days 3x1,000mg/day po, 7 days
(without visceral
Acyclovir has not been demonstrated to be harmless during involvement, moderate
pregnancy.
7,8
In fact, acyclovir is classified as a category B drug in the immunocompromise)
US Food and Drug Administration (FDA) use-in-pregnancy rating, so its
Famciclovir Famciclovir
use is not recommended during that time.
7,8
It is used only in cases in
2–3x250mg/day po, 3x500mg/day po, 7 days
7 days (without visceral involvement,
which a previous risk–benefit evaluation suggests that its use is
moderate immunocompromise)
advisable. With regard to endovenous acyclovir in mothers in the first
Brivudine Foscarnet
trimester of pregnancy, the rates of malformations have not been
1x125mg/day po, 7 days 2–3x60mg/kg per day IV
found to be higher than those in the general population. Use of
(contraindicated for 7–14 days, until complete
acyclovir is not routinely recommended in pregnant women except in patients treated healing of lesions
cases of complicated varicella (pneumonias), in which the risks of
with 5-fluorouracil or other
disease for the mother and for the foetus are high. In these cases,
5-fluoropyrimidines,
administration should be intravenous.
7,8
There is no information
because of drug
interaction associated with
available about the levels of acyclovir in human milk after oral or
severe and potentially fatal
intravenous administration of the drug. Breast-feeding is not
bone marrow suppression)
contraindicated if the mother is receiving or has received treatment
with acyclovir.
7,8
children are treated with acyclovir. This is the case despite the fact that
Treatment of Immunocompetent Children and Adults disappearance of the virus from cutaneous lesions is usually faster in
The effectiveness of acyclovir in the treatment of varicella in otherwise treated individuals.
16
Treatment with acyclovir is given to children and
healthy, immunocompetent children is not clear. Due to the drug’s adults who have a particular risk of suffering a complicated varicella.
limited clinical effectiveness, several studies have investigated the It has not been demonstrated that acyclovir treatment in healthy
possible induction of resistance and the increase in the pharmaceutical children yields sufficient benefits to indicate its use universally in all the
cost supposed by acyclovir.
11
In the paediatric literature there are young with varicella.
8,17
Following the above analysis, it is clear that
placebo-controlled tests in children.
12,13
In all of these the acyclovir acyclovir treatment in the immunocompetent, bearing in mind the
treatment was initiated early, within 24 hours of the onset of increased costs, can be indicated in adolescents over 12 years of age,
exanthema, and the drug was administered orally. From the data in adults (see Table 2) and in children less than 12 years of age who
obtained from studies in healthy children, it is concluded that when have intrafamily contact with the virus and are consequently potential
acyclovir is given early, within the first few hours of the illness victims of a more severe and complicated varicella.
(exanthema),
14
the duration of the illness is reduced slightly;
15
the time
before apparition of new lesions is reduced by a little more than a Treatment in Immunodepressed Children and Adults
day;
12,13
the total number of lesions diminishes significantly;
13
and the The use of nucleoside analogues is customary for the treatment of
days of fever are reduced by 1–1.4 days.
12,13
These conclusions are also varicella in the immunodepressed, aciclovir being the standard therapy
extrapolable to healthy adults. No clear reduction in the number of for those more severely affected. When acyclovir is administered
complications or their seriousness is apparent in healthy children. intravenously at the start of the illness, it is effective in reducing the
seriousness of the illness and in preventing death in both
This lack of data may also be related to the scarcity of varicella immunodepressed children and adults (see Table 2).
10–17
It is necessary
complications in these cases. In immunodepressed children treated to administer antiviral agents in their full doses and for sufficient time
with acyclovir, the appearance of resistance has been demonstrated. in order to prevent visceral dissemination of the infection. If the
In healthy children this aspect has not been tested but, in a scenario patient is not too affected by the illness, oral treatment with high-dose
of general treatment with acyclovir for all children with chickenpox, oral acyclovir, famciclovir or valacyclovir can be useful. The latter two
one might speculate that resistance would increase noticeably.
16
agents, as stated in their technical data sheets, are not authorised for
children under 12 years of age. In order to avoid varicella
There is no evidence that dissemination in group situations, such as complications it is critical to start treatment within the first few hours
the family, kindergarten or classroom, diminishes when the affected after exanthema appears.
16
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