| Study | Reason for exclusion |
|---|---|
| Aizawa 1972 | Not randomised. |
| Alvarez Rios 1994 | Dipyrone administered as rescue analgesic only. |
| Amata 1997 | Not randomised. |
| Atalay 1995 | Comparators both used extradural route. |
| Banos 1989 | Not a randomised controlled trial ‐ review. |
| Biscoping 1988 | Not a randomised controlled trial ‐ survey. |
| Blendinger 1980 | Short study duration (2 h). Small size (Dipyrone, n=7). |
| Bloch 1985 | Combination of dipyrone with another drug. |
| Bona 1985 | Baseline pain intensity not measured. |
| Bosch 1990 | Included children. |
| Cadenat 1974 | Not randomised or blind. |
| Casali 1981 | No data to extract ‐ short study duration (3 h). |
| Castro 2000 | Preventive analgesia. Patients with mild pain included in the study. |
| Castro Gonzalez 1986 | PCA methodology. PI scale non standard. |
| Chauvet 1986 | Not randomised. Not double blind. |
| Cirulli 1979 | Not randomised. Not double blind. |
| Classen 1985 | Not randomised. |
| Criscuolo 1989 | Open study. Combination of dipyrone with another drug. |
| da Silva Guido 1986 | Experimental pain ‐ not postoperative pain. |
| Daftary 1980 | Number of participants with moderate or severe pain not stated; included mild pain; nonstandard PR scale used. |
| Dagli 1995 | Intrapleural catheter. Baseline pain intensity not measured. |
| Farkas 1992 | Combination of dipyrone with another drug. |
| Fernandez 1991 | Single blind. |
| Ferrario 1984 | Baseline pain not measured. Non standard PI scale. Small size (n = 7). |
| Fugarolas Garza 1990 | Not a randomised controlled trial ‐ Review. |
| Gomez Jimenez 1980 | Non standard PI scale. |
| Goutaine 1975 | Not randomised or blind. |
| Guberti 1982 | Not randomised or blind. |
| Handwerker 1990 | Review chapter. |
| Hernandez 1997 | Not blind. |
| Herrera Barroso 1982 | Non standard PI and PR scales. |
| Hilgier 1997 | Not randomised or blind. |
| Kudo 1979 | Not randomised. |
| Lal 1973 | Short study duration (30 mins). Non standard PI and PR scales. |
| Le Grignou 1985 | Not randomised or blind. |
| Lehmann 1990 | PCA methodology. |
| Lopez Garrigo 1986 | Not randomised or blind. Preventive analgesia. |
| Marin Bertolin 1996 | Included mild pain. No single dose data. |
| Marin Bertolin 1997 | Duplicated data from Marin‐Bertolin 1996. |
| Martin Duce 1997 | Short study duration (1 h). |
| Martinez 1986 | Not randomised or blind. |
| Mehta 1967 | Not randomised or blind. |
| Mendoza 1979 | Not randomised or blind. |
| Moorthi 1970 | Combination of dipyrone with another drug. |
| Mukherjee 1980 | Non‐standard scales. |
| Nago 1967 | Not randomised. |
| Nikoda 1997 | Not randomised or blind. |
| Noronha 2009 | First dose administered preoperatively. |
| Ocampo Flores 1986 | Not randomised or blind. |
| Paeile 1974 | Not randomised or blind. |
| Pagliarini 1968 | Not a randomised controlled trial. |
| Panday 1968 | Not randomised or blind. |
| Parkar 1981 | Short study duration (3 h). |
| Petrakis 1972 | Not a randomised controlled trial. Combination of dipyrone with another drug. |
| Planas 1998 | Short study duration (1 h). |
| Portero 1991 | Small size (7 participants per group). |
| Quinones 1993 | Did not present hourly pain outcome data. |
| Radev 1995 | Not randomised or blind. |
| Reyes 1988 | No data to extract. |
| Rosas Perez 1986 | Not randomised or blind. |
| Santoso1992 | No usable data ‐ first dose data was contaminated. |
| Saray 2001 | Baseline pain not measured. No single dose data. |
| Savoca 1985 | Not randomised or blind. |
| Schmidt 1977 | Not randomised. |
| Sener 2008 | Intraoperative administration, not established pain. |
| Simm 1985 | Baseline pain intensity not assessed. No single dose data. |
| Steffen 1997b | PCA methodology. Combination of dipyrone with another drug. |
| Stelzner 1986 | Not a randomised controlled trial ‐ survey. |
| Szappanyos 1983 | Not randomised or blind. |
| Sznapka 1980 | Not randomised or blind. |
| Tigerstedt 1981 | Inappropriate method of randomisation ‐ by birth date. Combination of dipyrone with another drug. |
| Tulunay 1996 | No usable data ‐ first dose data contaminated; used nonstandard PI scale. Drugs were not identical in appearance. |
| Velez Rivera 1997 | Not randomised or blind. |
| Vergara 1998 | No data to extract. |
| Villareal Guzman 1993 | Small size (n = 8). |
| Weber 1971 | Not randomised. |
| Wieck 1970 | Combination of dipyrone with another drug. |
| Wolff 1971 | Not randomised. |
| Zieren 1999 | No data to extract. |
| Zucker 1997 | Not a randomised controlled trial ‐ review. |
| Zuev 1997 | Not randomised or blind. |
PCA=Patient controlled anaesthesia