Lamotrigine compared with placebo for painful diabetic neuropathy

Patient or population: neuropathic pain (three studies in painful diabetic neuropathy)

Settings: Community

Intervention: oral lamotrigine 200 to 400 mg daily

Comparison: placebo

At least 50% of maximum pain relief

RR 1.1 (0.82 to 1.4)

NNT not calculated

3 studies, 773 participants, 195 events

High

Unlikely that further research would reveal significant benefit, especially as potential high positive bias exists in the calculations we have because of LOCF imputation or completer analyses

Participants with at least 1 adverse event (all conditions)

RR 1.1 (1.01 to 1.2)

NNH 10 (6.5 to 27)

7 studies, 1121 participants, 768 events

High

Large numbers of events

Participants with a serious adverse event (all conditions)

Very low

No data

Participants with rash (all conditions)

RR 1.4 (1.01 to 2.0)

NNH 27 (16 to 89)

12 studies, 1715 participants, 138 events

Moderate

Modest number of events

Deaths (all conditions)

Very low

No data

GRADE Working Group grades of evidence
High quality: Further research is very unlikely to change our confidence in the estimate of effect.
Moderate quality: Further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate.
Low quality: Further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate.
Very low quality: We are very uncertain about the estimate.