Reviews: 70 studies.
Primary research:
17 trials (786 patients) of TENS for acute pain, 8 trials (712 women) for pain during labour, and 38 trials for chronic pain;
9 trials (414 patients) of relaxation;
8 trials (96 patients) of intravenous systemic regional blockade;
2 systematic reviews, including 15 trials (1,069 patients), of epidural corticosteroids;
1 systematic review, including 39 non-randomised trials, of spinal cord stimulators;
1 systematic review, including 22 trials, of corticosteroid injections;
20 trials of anticonvulsants;
21 trials of antidepressant drugs;
17 trials of systemic local anaesthetic type drugs;
11 trials (1,067 patients) of topical NSAIDs;
13 trials of topical capsaicin;
35 trials of cognitive-behavioural therapies.
Physical interventions.
TENS: TENS is not effective in post-operative labour pain. For chronic pain there is evidence that the effectiveness of TENS increases slowly, and that large doses need to be used. There is lack of evidence for the effectiveness of TENS in chronic pain.
Relaxation: there is a lack of evidence for effectiveness.
Intravenous systemic regional blockade: treatment with guanethidine is not effective.
Epidural corticosteroids: these are effective for short-term back pain and sciatica.
Spinal cord stimulators: there is a lack of evidence for effectiveness.
Injections of corticosteroids: injections in or around the shoulder joints are not effective for shoulder pain.
Pharmacological interventions.
Anticonvulsants and antidepressant drugs: the NNTs are of the order of 2.5, showing them to be effective. Minor adverse events are common, and major adverse events occur in about 1 in 20 patients.
Systemic local anaesthetic type drugs: these drugs are effective in nerve injury pain, but there is little or no evidence to support their use in migraine or cancer-related pain.
Topical NSAIDs: a pooled NNT of 3 was obtained for rheumatological conditions, showing them to be effective. Topical NSAIDs have few adverse events and are without the major gastrointestinal adverse events found with oral NSAIDs, which might make them an important choice for patients with peripheral arthritis.
Topical capsaicin: in diabetic neuropathy this treatment has an NNT of 4, showing them to be effective. Information on adverse events was not available.
Psychological approaches.
Cognitive-behavioural therapies: there is strong evidence for effectiveness across a wide range of mental health problems.