Efficacy and safety of gabapentin versus placebo to prevent the incidence of postherpetic neuralgia

ISRCTN ISRCTN79871784
DOI https://doi.org/10.1186/ISRCTN79871784
Secondary identifying numbers PI12_01813
Submission date
29/01/2013
Registration date
02/05/2013
Last edited
06/06/2019
Recruitment status
No longer recruiting
Overall study status
Completed
Condition category
Nervous System Diseases
Prospectively registered
Protocol
Statistical analysis plan
Results
Individual participant data

Plain English Summary

Background and study aims
Postherpetic neuralgia is thought to be nerve damage caused by herpes zoster virus. The damage causes nerves in the affected area of the skin to send abnormal electrical signals to the brain. The aim of this study is to analyse the efficacy of a drug gabapentin in patients 50 years old or above with moderate to severe pain during the acute phase of the herpes zoster in the prevention of the postherpetic neuralgia. The study's findings should help to reduce the percentage of patient that show postherpetic neuralgia during an episode of herpes zoster.

Who can participate?
Men and women aged 50 or above diagnosed or uncomplicated Herpes zoster within 72 hours of onset of the rash in patients with acute herpes zoster and with moderate/severe pain.

What does the study involve?
Participants are randomly allocated to take either gabapentin or placebo (dummy drug) for 5 weeks. At the end of the study, the prevalence of postherpetic neuralgia is compared in the placebo and gabapentin groups.

What are the possible benefits and risks of participating?
Gabapentin is an drug authorised by the European and American drugs agencies for the treatment of epilepsy and postherpetic neuralgia, both agencies has evaluated the safety of the gabapentin for the treatment of epilepsy and is not expected to be less safer in those patients with Herpes zoster. Patients treated with gabapentin for 5 weeks in the acute herpes zoster period plus valacyclovir and analgesic will reduce the incidence of postherpetic neuralgia by 25% compared to placebo.

Where is the study run from?
Primary Care Management of Mallorca

When is the study starting and how long is it expected to run for?
May 2013 to November 2015.

Who is funding the study?
Institute of Health Carlos III (Spain)

Who is the main contact?
Manel Rullán
mrullan@ibsalut.caib.es

Contact information

Mr Manuel Rullan
Scientific

Centro de Salud de Pollença; C/ BISBE DESBACH, S/N
Pollença
07460
Spain

Email aleiva@ibsalut.caib.es

Study information

Study designPhase III multi-centre double-blind placebo randomized clinical trial
Primary study designInterventional
Secondary study designRandomised controlled trial
Study setting(s)Hospital
Study typePrevention
Participant information sheet Not available in web format, please use the contact details to request a patient information sheet
Scientific titleEfficacy and safety of gabapentin versus placebo to prevent the incidence of PostHerpetic Neuralgia: a double-blinded clinical trial
Study acronymPHN
Study hypothesisPatient treated with gabapentin for 5 weeks in the acute herpes zoster period plus valacyclovir and analgesic will reduce the incidence of postherpetic neuralgia by 25% when compared to placebo plus valacyclovir and analgesic.
Ethics approval(s)Illes Balears ethics committee - approval pending
ConditionPostherpetic neuralgia
InterventionAntiviral therapy is first-line treatment and should be initiated within 72 hours of rash onset to increase the rate of healing and decrease pain, valacyclovir is also effective in the prevention of the postherpetic neuralgia, placebo and gabapentin groups will receive 1g/8h the first week.

Pain management: The WHO three-step "ladder" will be used for pain management.
If pain occurs, there should be prompt oral administration of drugs in the following order: non opioids (aspirin and paracetamol); then, as necessary, mild opioids (codeine); then strong opioids such as morphine, until the patient is free of pain.

Gabapentin or placebo treatment: effective dose should be individualized according to patient response and tolerability. The treatment should be started at a dose of 900 mg/d (300 mg/d on day 1, 600 mg/d on day 2, and 900 mg/d on day 3), then every 2 or 3 day an increase of 300mg depending up to a maximum doses of 3600mg/day. The treatment will end at 5 weeks, in the last week gabapentin or placebo will be gradually tapered.
Intervention typeDrug
Pharmaceutical study type(s)
PhasePhase III
Drug / device / biological / vaccine name(s)Gabapentin, valacyclovir
Primary outcome measurePrevalence of postherpetic neuralgia, assessed using the Visual Analog Scale (VAS >0) at 12 weeks
Secondary outcome measures1. Prevalence of postherpetic neuralgiaa, assessed using the Visual Analog Scale (VAS >0) at 6 weeks
2. Percentage of patients with a reduction of at least 50% in the VAS scale
Overall study start date15/05/2013
Overall study end date15/11/2015

Eligibility

Participant type(s)Patient
Age groupAdult
SexBoth
Target number of participants254 patients
Total final enrolment98
Participant inclusion criteria1. Patient aged 50 or above, either sex
2. Patient diagnosed or uncomplicated herpes zoster within 72 hours of onset of the rash in patients with acute herpes zoster and with moderate/severe pain (Analogic visual scale ≥ 4)
Participant exclusion criteria1. Patients taking gabapentin
2. Patients diagnosed of severe hepatic impairment, hypersensitivity to gabapentin or excipients, acute renal failure or renal impairment (Clcr <79ml/min)
3. Patients with evidence of cutaneous or visceral dissemination of herpes zoster infection (cutaneous dissemination is defined as 20 discrete lesions outside adjacent dermatomes) or ocular dissemination
4. Immunocompromised state and/or interferon treatment in the last 4 weeks
5. Patient taking tricyclic antidepressants or corticoids in the inclusion or treatment period
Recruitment start date15/05/2013
Recruitment end date15/11/2015

Locations

Countries of recruitment

  • Spain

Study participating centre

Centro de Salud de Pollença; C/ BISBE DESBACH, S/N
Pollença
07460
Spain

Sponsor information

Primary Care Management of Mallorca (Gerencia de Atención Primaria de Mallorca) (Spain)
Government

Funders

Funder type

Hospital/treatment centre

Instituto de Salud Carlos III (ref: PI12_01813)
Government organisation / National government
Alternative name(s)
SaludISCIII, InstitutodeSaludCarlosIII, Instituto de Salud Carlos III | Madrid, Spain, Carlos III Institute of Health, Institute of Health Carlos III, Carlos III Health Institute, ISCIII
Location
Spain

Results and Publications

Intention to publish date
Individual participant data (IPD) Intention to shareNo
IPD sharing plan summaryNot provided at time of registration
Publication and dissemination planNot provided at time of registration
IPD sharing plan

Study outputs

Output type Details Date created Date added Peer reviewed? Patient-facing?
Protocol article protocol 14/01/2017 Yes No
Results article results 05/06/2019 06/06/2019 Yes No

Editorial Notes

06/06/2019: The following changes were made to the trial record:
1. Publication reference added.
2. The total final enrolment was added.
16/01/2017: Publication reference added.