2. Publication bias risk assessment: safety outcomes.
| Comparison/outcome | Number of studies | Number of participants | n with outcome/total | % with outcome | Risk difference | NNH | Susceptibility to publication bias | ||
| Active | Control | Active | Control | ||||||
| Comparison 11. Number of participants with adverse events | |||||||||
| 1 Paracetamol or propacetamol vs placebo | 20 | 2359 | 557/1278 | 400/1081 | 44 | 37 | 0.04 (0.01 to 0.08) | 25 | NNH > 10 |
| 1.2 Propacetamol vs placebo | 10 | 1409 | 278/740 | 197/669 | 38 | 29 | 0.05 (0.01 to 0.10) | 20 | NNH > 10 |
| Comparison 14. Number of participants withdrawing due to lack of efficacy | |||||||||
| 1.2 Propacetamol vs placebo | 14 | 889 | 25/477 | 47/412 | 5 | 11 | ‐0.05 (‐0.08 to ‐0.02) | 20* | NNH > 10 |
| Comparison 15. Number of participants with pain on infusion | |||||||||
| 2. Propacetamol vs placebo | 6 | 645 | 75/333 | 4/312 | 23 | 1 | 0.20 (0.16 to 0.24) | 5 | 645 |
| 3. Propacetamol vs paracetamol | 3 | 362 | 71/182 | 8/180 | 39 | 4 | 0.35 (0.27 to 0.42) | 3 | 904 |
| Comparison 16. Individual adverse events: paracetamol or propacetamol vs placebo | |||||||||
| 1. Nausea: Paracetamol or propacetamol vs placebo | 15 | 1267 | 189/660 | 213/607 | 29 | 35 | ‐0.05 (‐0.10 to ‐0.01) | 20* | NNH > 10 |
| 1.1. Nausea: Paracetamol vs placebo | 13 | 1037 | 153/520 | 196/517 | 29 | 38 | ‐0.09 (‐0.14 to ‐0.04) | 11* | NNH > 10 |
| 2. Vomiting: Paracetamol or propacetamol vs placebo | 15 | 1414 | 103/721 | 144/693 | 14 | 21 | ‐0.06 (‐0.10 to ‐0.03) | 17* | NNH > 10 |
| 2.1. Vomiting: Paracetamol vs placebo | 13 | 1037 | 88/520 | 136/517 | 17 | 26 | ‐0.10 (‐0.14 to ‐0.05) | 10* | NNH > 10 |
| Comparison 18. Individual adverse events: paracetamol or propacetamol vs opioids | |||||||||
| 1. Nausea: Paracetamol or propacetamol vs opioids | 6 | 545 | 19/272 | 48/273 | 7 | 18 | ‐0.11 (‐0.16 to ‐0.05) | 10* | 55 |
| 1.1 Nausea: Paracetamol vs opioids | 4 | 438 | 12/219 | 39/219 | 5 | 18 | ‐0.12 (‐0.18 to ‐0.07) | 9* | 88 |
| 2. Vomiting: Paracetamol or propacetamol vs opioids | 5 | 495 | 6/247 | 20/248 | 2 | 8 | ‐0.06 (‐0.09 to ‐0.02) | 17* | NNH > 10 |
| 2.1. Vomiting: Paracetamol vs opioids | 3 | 388 | 4/194 | 16/194 | 2 | 8 | ‐0.06 (‐0.10 to ‐0.02) | 17* | NNH > 10 |
| 6.1. Sedation: Paracetamol vs opioids | 3 | 354 | 2/176 | 26/178 | 1 | 15 | ‐0.14 (‐0.18 to ‐0.09) | 8* | 142 |
*lower occurrence of adverse event in paracetamol and/or propacetamol arm