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Three Part Question

In [patients with new onset of herpes zoster infection], can [pregabalin] be used to [decrease the incidence of post-herpetic neuralgia and to decrease the intensity of acute herpetic pain]?

Clinical Scenario

A 62-year-old man comes in with a new vesicular rash on his abdomen that has been present for 24 h. He complains of intense pain and tenderness in the same area as the rash. You diagnose herpes zoster. You start an antiviral medication right away, but you wonder what medication you could use to try to alleviate the patient's pain and reduce the incidence of post-herpetic neuralgia. You have seen your colleagues use pregabalin for that purpose, but wonder if there is good evidence to support this practice.

Search Strategy

Pubmed Advanced Search via Search Builder 14 December 2011: (Herpes zoster[MeSH Terms] AND Neuralgia[MeSH Terms] OR Postherpetic neuralgia[MeSH Terms]) AND Pregabalin Limits: Humans, English.

EMBASE search 20 October 2011: ‘Herpes zoster’ AND ‘Neuralgia’ OR ‘Postherpetic neuralgia’ AND ‘Pregabalin’ Limits: all years, humans, >18-years-old, controlled clinical trials or RCT, English or French, article or article in press:
The website http://www.clinicaltrials.gov was searched for an ongoing trial on the topic, and one trial was found.

Twenty-one articles found in Embase and 47 in Medline. One was relevant and of sufficient quality for inclusion

Search Outcome

Search outcome:
• EMBASE: 21 articles found.
• MEDLINE: 19 citations, no new reference.
• 1 paper was relevant to the question.

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Nevenka Krčevski Škvarč, Mirt Kamenik 2010 Slovania	29 outpatients aged between 30 and 80 years. All had a pain score ≥4 on a Likert scale (0–10) despite naproxen, recruited from day 7 to day 14 of disease. Treatment was with 75 mg pregabalin twice daily or placebo; the dose could be doubled at subsequent visits. Additional analgesia was allowed.	Prospective double-blind randomized placebo-controlled study	Pain severity (primary outcome)	No statistically significant difference	Very low power so high chance of a type II error, results not applicable to young adults, many patients withdrew from the study before completion, not done in an ED setting, not clear if patients lost to follow-up, concomitant analgesia could be a confounding factor
			Supplemental analgesia	No statistically significant difference
			Occurrence of postherpetic neuralgia	No statistically significant difference

Comment(s)

Herpes zoster is a pathology frequently encountered in the Emergency Department. The acute pain associated to this condition is often debilitating to the patient, as is the less frequent postherpetic neuralgia, which affects 10%–15% after the acute phase. Many patients have an unsatisfactory response to conventional treatment and it would be useful to have other effective drugs available to treat them. Unfortunately, there was no article in the literature that conclusively answered the question posed. The website http://www.clinicaltrials.gov was searched for an ongoing trial on the topic, and one trial was found: ‘Placebo-Controlled Study of Pregabalin for the Pain of Acute Herpes Zoster’. The published results of this trial (2) only included eight patients and it is not included here. A trial of sufficient power studying the effect of the drug at the moment herpes zoster is diagnosed would be useful.

Clinical Bottom Line

Pregabalin does not seem to decrease the intensity of pain related to acute herpes zoster. Moreover, it does not decrease the incidence of post herpetic neuralgia.

References

1. Krcevski Skvarc N, Kamenik M Effects of pregabalin on acute herpetic pain and postherpetic neuralgia incidence Wien Klin Wochenschr 2010; 49-53
2. Jensen-Dahm C, Rowbotham MC, Reda H, et al. Effect of a single dose of pregabalin on herpes zoster pain. Trials 2011;12:55.