Scolaris Content Display Scolaris Content Display

Study flow diagram for the updated search
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Figure 1

Study flow diagram for the updated search

Risk of bias summary: review authors' judgements about each risk of bias item for each included study.
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Figure 2

Risk of bias summary: review authors' judgements about each risk of bias item for each included study.

Forest plot of comparison: 1 Tramadol versus placebo, outcome: 1.1 Participants with ≥ 50% pain intensity reduction.
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Figure 3

Forest plot of comparison: 1 Tramadol versus placebo, outcome: 1.1 Participants with ≥ 50% pain intensity reduction.

Comparison 1 Tramadol versus placebo, Outcome 1 Participants with ≥ 50% pain intensity reduction.
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Analysis 1.1

Comparison 1 Tramadol versus placebo, Outcome 1 Participants with ≥ 50% pain intensity reduction.

Comparison 1 Tramadol versus placebo, Outcome 2 Withdrawal due to adverse events.
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Analysis 1.2

Comparison 1 Tramadol versus placebo, Outcome 2 Withdrawal due to adverse events.

Comparison 1 Tramadol versus placebo, Outcome 3 All cause withdrawal.
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Analysis 1.3

Comparison 1 Tramadol versus placebo, Outcome 3 All cause withdrawal.

Comparison 1 Tramadol versus placebo, Outcome 4 Participants with any adverse event.
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Analysis 1.4

Comparison 1 Tramadol versus placebo, Outcome 4 Participants with any adverse event.

Comparison 1 Tramadol versus placebo, Outcome 5 Participants with specific adverse events.
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Analysis 1.5

Comparison 1 Tramadol versus placebo, Outcome 5 Participants with specific adverse events.

Summary of findings for the main comparison. Tramadol compared with placebo for neuropathic pain

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

Outcomes

(at trial end)

Probable outcome with
tramadol

Probable outcome with
placebo

Relative effect
(95% CI)

No of participants
(studies)

Quality of the evidence
(GRADE)

Comments

At least 30% reduction in pain

Not analysed

Not analysed

Not analysed

157 participants

(2 studies)

60 events

Low quality1

At least 50% reduction in pain

530 per 1000

300 per 1000

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

Not analysed

Not analysed

35 participants

(1 study)

4 events

Very low quality2

Withdrawal due to adverse event

160 per 100

30 per 1000

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

580 per 1000

340 per 1000

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

4 serious adverse events reported in total

Not all studies reported specifically on serious adverse events

Very low quality2

Death

No data

No data

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.

1Downgraded 2 levels due to small number of studies and participants and relatively few events, and several sources of potential bias.
2Downgraded 3 levels due to small number of studies, and participants and events, and several sources of potential bias.
3No events.

Figures and Tables -
Summary of findings for the main comparison. Tramadol compared with placebo for neuropathic pain
Comparison 1. Tramadol versus placebo

Outcome or subgroup title

No. of studies

No. of participants

Statistical method

Effect size

1 Participants with ≥ 50% pain intensity reduction Show forest plot

3

265

Risk Ratio (M‐H, Random, 95% CI)

2.16 [1.02, 4.58]

2 Withdrawal due to adverse events Show forest plot

6

485

Risk Ratio (M‐H, Fixed, 95% CI)

4.08 [1.99, 8.37]

3 All cause withdrawal Show forest plot

3

202

Risk Ratio (M‐H, Fixed, 95% CI)

1.15 [0.75, 1.76]

4 Participants with any adverse event Show forest plot

4

266

Risk Ratio (M‐H, Fixed, 95% CI)

1.61 [1.22, 2.13]

5 Participants with specific adverse events Show forest plot

6

Risk Ratio (M‐H, Fixed, 95% CI)

Subtotals only

5.1 Nausea

6

508

Risk Ratio (M‐H, Fixed, 95% CI)

3.62 [2.23, 5.88]

5.2 Constipation

5

381

Risk Ratio (M‐H, Fixed, 95% CI)

4.11 [2.36, 7.16]

5.3 Tiredness/fatigue/somnolence

4

345

Risk Ratio (M‐H, Fixed, 95% CI)

3.22 [1.93, 5.36]

5.4 Dizziness

3

214

Risk Ratio (M‐H, Fixed, 95% CI)

3.72 [1.94, 7.12]

5.5 Dry mouth

3

214

Risk Ratio (M‐H, Fixed, 95% CI)

2.44 [1.35, 4.42]

Figures and Tables -
Comparison 1. Tramadol versus placebo