Tramadol compared with placebo for neuropathic pain

Patient or population: adults with neuropathic pain (any origin)

Settings: community

Intervention: oral tramadol (typically started at a dose of about 100 mg daily and increased over 1 to 2 weeks to a maximum of 400 mg daily)

Comparison: placebo

At least 30% reduction in pain

Not analysed

157 participants

(2 studies)

60 events

Low quality¹

‐

At least 50% reduction in pain

RR 2.2 (1.02, 4.6)

NNT 4.4 (2.9 to 8.8)

265 participants

(3 studies)

110 events

Low quality¹

‐

PGIC much or very much improved

Not analysed

35 participants

(1 study)

4 events

Very low quality²

‐

Withdrawal due to adverse event

RR 4.1 (2.0 to 8.4)

NNH 8.2 (5.8 to 14)

485 participants

(6 studies)

45 events

Low quality¹

‐

Participants experiencing any adverse event

RR 1.6 (1.2 to 2.1)

NNH 4.2 (2.8 to 8.3)

266 participants

(4 studies)

123 events

Low quality¹

‐

Serious adverse events

Not all studies reported specifically on serious adverse events

Very low quality²

‐

Death

Not calculated

No data

Very low quality³

‐

CI: confidence interval; NNH: number needed to treat for one additional harmful outcome; PGIC: Patient Global Impression of Change; RR: risk ratio

Descriptors for levels of evidence (EPOC 2015):
High quality: this research provides a very good indication of the likely effect. The likelihood that the effect will be substantially different^† is low.
Moderate quality: this research provides a good indication of the likely effect. The likelihood that the effect will be substantially different^† is moderate.
Low quality: this research provides some indication of the likely effect. However, the likelihood that it will be substantially different^† is high.
Very low quality: this research does not provide a reliable indication of the likely effect. The likelihood that the effect will be substantially different^† is very high.

^† Substantially different: a large enough difference that it might affect a decision.