Methadone compared with placebo for neuropathic pain

Patient or population: adults with chronic neuropathic pain

Settings: community

Intervention: methadone, orally, various doses

Comparison: placebo

Moderate benefit:
at least 30% reduction
in pain, or
PGIC much or very
much improved

Not calculated

2 studies, 29 participants, 18 events

⊕⊝⊝⊝
Very low

Downgraded 3 times:
2 heterogeneous, short duration, cross‐over studies; mixed diagnoses; few participants and events.

Substantial benefit:
at least 50% reduction
in pain, or
PGIC much improved

Not calculated

1 study, 19 participants, 0 events

⊕⊝⊝⊝
Very low

Downgraded 3 times:
single, short duration, cross‐over study; few participants, mixed diagnoses, and 0 events.

Withdrawals due to lack of efficacy

Not calculated

2 studies, 29 participants, 0 events

⊕⊝⊝⊝
Very low

Downgraded 3 times:
2 heterogeneous, short duration, cross‐over studies; mixed diagnoses; data incompletely presented; few participants and 0 events.

Withdrawals due toadverse event withdrawal

Not calculated

2 studies, 29 participants, 7 events

⊕⊝⊝⊝
Very low

Downgraded 3 times:
2 heterogeneous, short duration, cross‐over studies; mixed diagnoses; data incompletely presented; few participants and events.

Participants experiencing anyserious adverse
events

‐

‐

⊕⊝⊝⊝
Very low

‐

Deaths

‐

‐

⊕⊝⊝⊝
Very low

‐

CI: confidence interval.

GRADE Working Group grades of evidence

High quality: we are very confident that the true effect lies close to that of the estimate of the effect.

Moderate quality: we are moderately confident in the effect estimate; the true effect is likely to be close to the estimate of effect, but there is a possibility that it is substantially different.

Low quality: our confidence in the effect estimate is limited; the true effect may be substantially different from the estimate of the effect.

Very low quality: we have very little confidence in the effect estimate; the true effect is likely to be substantially different from the estimate of effect.