Injectable ketorolac for postoperative pain

Clinical bottom line: A single dose of intramuscular ketorolac 30 mg had an NNT of 3.4 (2.5 to 4.9) for at least 50% pain relief over 4-6 hours in patients with moderate or severe pain compared with placebo. This is not as effective as intramuscular morphine 10 mg which has an NNT of 2.9 (2.6-3.6). 10 mg doses of intramuscular and intravenous ketorolac and also provide significant pain relief with NNTs of 5.7 (3.0 to 53) and 3.4 (2.1 to 7.9) respectively. However, this is based on small numbers of patients, and should be interpreted with caution.

There were no serious adverse effects reported for any dose of ketorolac.

Ketorolac for pain relief

Ketorolac is a non-steroidal anti-inflammatory drug (NSAID) which is licensed for short term use in the management of moderate to severe postoperative pain. Injected NSAIDs are a popular alternative to injected opioids in acute pain management.

Systematic review

Smith LA, Carroll D, Edwards JE, Moore RA, McQuay HJ. Single dose ketorolac and pethidine in acute postoperative pain: a systematic review. (Unpublished).

Date review completed: July 1998
Number of trials included: 6 intramuscular, 1 intravenous
Control group: placebo
Main outcomes: pain relief at 4-6 hours (TOTPAR / SPID), Number-needed-to-treat (NNT) (with 95% confidence intervals), relative benefit and relative risk (with 95% confidence intervals).

Inclusion criteria were randomised, double-blind, placebo controlled trials of intramuscular or intravenous ketorolac in postoperative pain; adult patients; baseline pain of moderate to severe intensity; oral and/or intramuscular administration; pain outcome at least four hours.

Mean TOTPAR and SPID values for each trial were converted to %maxTOTPAR and %maxSPID, and then the proportion of patients achieving at least 50%maxTOTPAR were calculated. This information was used to calculate numbers-needed-to-treat and relative benefit. Adverse effects frequency data were used to calculate numbers-needed-to-harm and relative risk.

Findings

Ketorolac 10 mg intramuscular

Two trials in 142 patients were included. Ketorolac was significantly more effective than placebo, with an NNT of 5.7 (3.0 to 53).

Ketorolac 30 mg intramuscular

Five trials in 359 patients were included. Ketorolac was significantly more effective than placebo, with an NNT of 3.4 (2.5 to 4.9).

Ketorolac 60 mg intramuscular

One trial with 116 patients was included. Ketorolac was significantly more effective than placebo, with an NNT of 1.8 (1.5 to 2.3).

Ketorolac 10 mg intravenous

One trial with 74 patients was included. Ketorolac was significantly more effective than placebo, with an NNT of 3.4 (2.1 to 7.9).

Table: Summary of relative benefit and number-needed-to-treat for at least 50% pain relief in trials of intramuscular and intravenous ketorolac compared with placebo

Dose	Route	Number of trials	Ketorolac At least 50% pain relief Number/Total	Placebo At least 50% pain relief Number/Total	Relative Benefit (95% CI)	NNT (95%CI)
10 mg	IM	2	33/69	22/73	1.6 (1.1 to 2.4)	5.7 (3.0 to 53)
30 mg	IM	5	93/176	42/183	2.3 (1.8 to 3.1)	3.4 (2.5 to 4.9)
60 mg	IM	1	45/81	0/35	40 (2.5 to 626)	1.8 (1.5 to 2.3)
10 mg	IV	1	13/37	2/37	6.5 (1.6 to 27)	3.4 (2.1 to 7.9)

Adverse effects

There were no serious adverse effects reported for any dose of ketorolac. One patient withdrew due to dry mouth with 30 mg intramuscular ketorolac. At 10 mg and 30 mg all adverse effects were considered clinically non-serious and were described as being of mild or moderate severity.