Table 10.
Rat efficacy studies of nonopioid analgesics
| Agent | Dose (mg/kg) | Route | Test | Duration of action | Comments | Ref |
| Acetaminophen | 100, 300 | PO | VF | No effect | Dosed daily for 2 d | 196 |
| 20-1000 | PO | HP, TNT, VF | 30-120 min at 100 and 1000 mg/kg | VF ED50 32.8 mg/kg | 188 | |
| 4.48 mg/mL | PO-W | SX | No effect | 27 | ||
| Carprofen | 2 | PO-G | PW, VF | 6-9 h | 201 | |
| 5 | PO-G | SX, VF, HP | Up to 48 h | Medicated feed provided 2 d preoperative and 2 d postoperative. Reduced mechanical pain, but not thermal. | 184 | |
| 5 | SC | Lap | Dosed preoperative and 4 and 24 h postoperative. Increased activity | 23 | ||
| 5 | SC | Lap | 270-390 min | Observation limited to 390 min postoperative | 176 | |
| 5, 10 | SC | CFA | No effect | 166 | ||
| Gabapentin | 25-200 | IP | FT | Effective at 100 and 200 mg/kg | 157 | |
| 30-300 | IP | CCI TF, VF | TF increase at 300 mg/kg; VF ED50 34 mg/kg; cold allodynia ED50 103 mg/kg | 95 | ||
| 5-20 | IP | HP, VF | Increase thresholds 10-20 mg/kg | 81 | ||
| 300 | PO | CFA | No effect | 139 | ||
| 30-300 | PO-G | RS | 1-4 h at 300 mg/kg | 85 | ||
| 02-4 h at 100 mg/kg | ||||||
| 3 h at 30 mg/kg | ||||||
| 10-100 | SC | VF | Nominal effect at 100 mg/kg | 167 | ||
| 90 | SC | TF | 30-90 min | 146 | ||
| Ibuprofen | 0.3-30 | PO | CFA | No return to baseline gait | 139 | |
| 20 | PO | SX | Dosed q8-12h for 120 h. Improved gait | 27 | ||
| 31, 100 | SC | CFA | WT bearing within 30-90 min; | Rearing increase at 100 mg/kg; Burrowing increased | 178 | |
| Ketoprofen | HP, PW | 6 h at 30-100 mg/kg | 68 | |||
| 3 | IM | Lap, TF | Dosed q12h for 72 h. No effect | 41 | ||
| 3,5 | IM | Lap | Dosed preoperative and 9-12 h postoperative. Reduced BW and FI; single and double dose have similar effect | 40 | ||
| 1,3.2,10 | PO | HP | 30-60 min | ED90 3.2 and 10 mg/kg | 4 | |
| 0.5-10 | SC | PW, VF | Guarding reduced 2-24 h at 5 and 10 mg/kg; no effect on PW or VF | 195 | ||
| 40 | SC | Lap | Reduced RGS similar to morphine | 111 | ||
| Meloxicam | 1 | SC | Lap | Dosed daily for 3 d. Lower ethogram score; no difference from 2 mg/kg dose | 160 | |
| 2 | SC | Lap | Dosed daily for 3 d. Lower ethogram score | 160 | ||
| 2, then 1 | SC | Lap | Dosed daily for 3 d. Improved BW, FI | 20 | ||
| 4.0 SRzp | SC | SX, VF, HP | Up to 48 h | Reduced mechanical pain, but not thermal. | 184 | |
| Naproxen | 50-100 | IP | CFA | Weight bearing increased at 30 min; increase burrowing | 178 | |
| 50-150 | IP | CFA | Effective at 50 mg/kg; higher dose no benefit | 177 | ||
| Tramadol | 0.625-40 | IP | HP, VF | ED50 10 mg/kg; ED80 40 mg/kg | 144 | |
| 10 | IP | HP | Dosed q12h for 60 h. In effective | 141 | ||
| 10-30 | IP | HP | ED40 30 mg/kg | 65 | ||
| 10-40 | IP | VF | 15-30 min at 20 mg/kg; 15-120 min at 40 mg/kg | 116 | ||
| 11 | IP | TF | 75 min | 218 | ||
| 12.5 | IP | Lap | Dosed preoperative and 4 and 24 h postoperative. No effect on activity, wheel running, BW | 23 | ||
| 1-25 | IP | TF | Increase latency at 15 and 25 mg/kg; motor function impaired > 15 mg/kg | 135 | ||
| 4-50 | IP | HP, TF | Increase latency at 12.5-50 mg/kg; heavy sedation > 25 mg/kg | 24 | ||
| 5-20 | IP | CFA | 60-90 min | Increase latency at 10 and 20 mg/kg | 214 | |
| 5-40 | IP | TF | 30-120 min | ED50 20 mg/kg; ED80 40 mg/kg | 100 | |
| 3-30 | PO | HP, TNT, VF | 30-120 min at 10 and 30 mg/kg | VF ED50 4.8 mg/kg | 188 | |
| 4-50 | PO-J | HP, TF | No effect | 24 | ||
| 0.45 | SC | TF | 30-90 min | 162 | ||
| 20 | SC | FT | Reduced pain scores | 67 | ||
| 4-50 | SC | HP, TF | Increased latency at 25-50 mg/kg; heavy sedation | 24 | ||
PO-W = oral in water; PO-G = oral by gavage; PO-J = oral in gelatin; SX = surgical model; Lap = Laparotomy; TNT = tibial nerve translocation; CCI = chronic constriction injury
CLP = cecal ligation and puncture; CFA = Complete Freund’s adjuvant; DN = diabetic neuropathy; FT = Formalin test; HP = hot plate assay; RS = Randall-Selitto test; TF = tail-flick assay; VF = von Frey test; zP = manufactured by Zoopharm, Windsor, CO