Study designs of evaluations included in the review
Randomised controlled trials (RCTs) were eligible. Both parallel-group and crossover trials were included. Trials scoring one point on the validity scale were generally excluded. The exceptions were two RCTs that could not be adequately blinded.
Specific interventions included in the review
The inclusion criteria for the interventions were not specified and any treatments were eligible. The following treatments were included:
topical therapies compared with placebo (lidocaine patch, capsaicin 0.075% cream and benzydamine cream);
comparisons of amitriptyline, lorazepam, fluphenazine, amitriptyline- fluphenazine combination, nortriptyline, maprotiline or desipramine with placebo or each other;
tramadol compared with clomipramine with and without levomepromazine;
comparisons of gabapentin, oxycodone controlled-release, dextromethorphan, memantine or acyclovir with placebo;
vincristine iontophoresis compared with saline iontophoresis;
acupuncture compared with mock and actual transcutaneous electrical nerve stimulation;
intrathecal lidocaine with and without methylprednisolone compared with no treatment;
intrathecal compared with epidural methylprednisolone;
a mixture of gangliosides (Cronassial) compared with placebo; and
bupivacaine sympathetic blocks compared with intravenous lidocaine.
The duration of the treatments ranged from 2 days to 12 weeks.
Participants included in the review
PHN. Patients with PHN, i.e. those with a history of zoster, pain in the dermatomal distribution of the zoster rash, and pain persisting or occurring after cutaneous healing of zoster, were eligible. Most of the included patients had suffered from PHN for more than 1 year.
Outcomes assessed in the review
Studies with evaluation periods lasting longer than 24 hours, which addressed pain resolution, pain severity or quality of life, were eligible. Pain was assessed on the basis of visual analogue scores, a 50% reduction in pain scores, 50% pain relief, and categorical ratings. Adverse effects were also evaluated. The duration of the follow-up ranged from 2 days to 2 years.
How were decisions on the relevance of primary studies made?
The authors do not state how the papers were selected for the review, or how many of the reviewers performed the selection. [A:Both authors independently evaluated studies for inclusion based on pre-determined inclusion criteria. Any disagreements were resolved by discussion]