Table 2. Characteristics of 44 Included Studies .
| Characteristic | Studies, No. (%) (N = 44) |
|---|---|
| Study type | |
| Randomized clinical trial | 30 (68) |
| Cohort study | 14 (32) |
| Study region | |
| United States or Canada | 16 (36) |
| Europe | 12 (27) |
| Asia | 12 (27) |
| Africa | 3 (6) |
| Australia/New Zealand | 1 (2) |
| Year of publication | |
| 2020-2023 | 4 (9) |
| 2010-2019 | 11 (25) |
| 2000-2009 | 13 (30) |
| 1990-1999 | 6 (14) |
| 1980-1989 | 7 (16) |
| 1970-1979 | 1 (2) |
| 1960-1969 | 2 (4) |
| Pain syndrome | |
| Low back pain | 5 (11) |
| Fibromyalgia | 11 (25) |
| Headache or trigeminal neuralgia | 10 (23) |
| Cramps or painful spasticity | 10 (23) |
| Other | 8 (18) |
| Muscle relaxant | |
| Baclofen | 11 (25) |
| Tizanidine | 8 (18) |
| Cyclobenzaprine | 7 (16) |
| Eperisone | 5 (11) |
| Quinine | 3 (7) |
| Carisoprodol | 3 (7) |
| Orphenadrine | 3 (7) |
| Chlormezanone | 2 (4) |
| Methocarbamol | 2 (4) |
| Intervention duration | |
| 4 wk | 13 (30) |
| 4-12 wk | 24 (56) |
| >12 wk | 7 (16) |