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4-16 THE EFFECT OF TREATING HERPES ZOSTER
WITH ORAL ACYCLOVIR IN PREVENTING POST HERPETIC NEURALGIA
Treatment of HZ with oral acyclovir within 72 hours of
rash onset may reduce the incidence of residual pain at 6
months. Archives Int. Med. April 28, 1997; 157: 909-12 4-16 THE EFFECT OF TREATING HERPES
ZOSTER WITH ORAL ACYCLOVIR IN PREVENTING POST HERPETIC
NEURALGIA
A meta-analysis
Up to 1 of older patients with herpes zoster
(HZ) experience some residual pain in the distribution of
the rash several months after healing. Despite numerous
randomized clinical trials, the effect of treating HZ in
preventing post herpetic neuralgia (PHN) remains
uncertain. Results of investigations have been
conflicting.
This meta-analysis assessed the effect of acyclovir on
incidence of PHN.
Conclusion: Acyclovir [Zovirax] therapy was associated
with a reduced incidence of PHN at 6 months.
STUDY
- Meta analysis found 5
placebo-controlled trials which were homogeneous.
(Treatment was begun within 72-h of appearance of
the rash.) The studies were combined for
analysis.
- Calculated the
summary odds ratio for the incidence of any pain
in the distribution of the rash at 6 months.
RESULTS
- The odds ratio any
pain at 6 months in those treated with acyclovir
(800 mg 5x for 7-10 days) vs controls was 0.54.
(95% confidence interval 0.31-0.81).
- The absolute risk
reduction was 0.16. Number of patients needed to
treat (NNT) to prevent 1 case of PHN = 6.
DISCUSSION
- Variation in the
definition and reporting of PHN created problems
in data extraction. Some studies provided data on
both the presence of any pain and the presence of
severe disabling pain, while others provided data
on only the presence of any pain. This analysis
used the presence of any pain. The severity of
pain and magnitude of pain reduction by treatment
is thus uncertain.
- "Because herpes
zoster is common, and PHN occurs in up to 1 of
untreated patients, our findings, which suggest
that patients treated within 72 hours of rash
onset may experience a 46% reduction in the
incidence of pain in the distribution of the rash
at 6 months." This may be clinically
significant.
CONCLUSION
Treatment of HZ with oral acyclovir within 72 hours of
rash onset may reduce the incidence of residual pain at 6
months.
Archives Int. Med. April 28, 1997; 157: 909-12
Original investigation first author from Madigan Army
Medical Center, Tacoma, Wash.
Comment
This is the first study I have read that came to this
conclusion. If treatment is decided on one might choose
valcyclovir [Valtrex] or famcyclovir [Famvir] because of
simplicity of dosage. I believe these drugs remain
investigational. There is still no solid evidence of
effectiveness in preventing PHN. Clinicians must decide
for individual patients on the basis of the ratio between
putative benefit and possible harm + cost. If I develop
severe HZ I would opt for treatment with both famcyclovir
and prednisone to reduce acute discomfort, hasten
healing, and possibly to reduce likelihood of PHN. RTJ
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