JOURNAL ARTICLE
RANDOMIZED CONTROLLED TRIAL

Low-dose ketamine improves pain relief in patients receiving intravenous opioids for acute pain in the emergency department: results of a randomized, double-blind, clinical trial

Francesca L Beaudoin, Charlie Lin, Wentao Guan, Roland C Merchant
Academic Emergency Medicine 2014, 21 (11): 1193-202
25377395

OBJECTIVES: Low-dose ketamine has been used perioperatively for pain control and may be a useful adjunct to intravenous (IV) opioids in the control of acute pain in the emergency department (ED). The aim of this study was to determine the effectiveness of low-dose ketamine as an adjunct to morphine versus standard care with morphine alone for the treatment of acute moderate to severe pain among ED patients.

METHODS: A double-blind, randomized, placebo-controlled trial with three study groups was conducted at a large, urban academic ED over a 10-month period. Eligible patients were 18 to 65 years old with acute moderate to severe pain (score of at least 5 out of 10 on the numerical pain rating scale [NRS] and pain duration < 7 days) who were deemed by their treating physician to require IV opioids. The three study groups were: 1) morphine and normal saline placebo (standard care group), 2) morphine and 0.15 mg/kg ketamine (group 1), or 3) morphine and 0.3 mg/kg ketamine (group 2). Participants were assessed at 30, 60, and 120 minutes after study medication administration and received rescue analgesia as needed to target a 50% reduction in pain. The primary outcome measure of pain relief, or pain intensity reduction, was derived using the NRS and calculated as the summed pain-intensity (SPID) difference over 2 hours. The amount and timing of rescue opioid analgesia was evaluated as a secondary outcome. The occurrence of adverse events was also measured.

RESULTS: Sixty patients were enrolled (n = 20 in each group). There were no differences between study groups with respect to age, sex, race/ethnicity, preenrollment analgesia, or baseline NRS. Over the 2-hour poststudy medication administration period, the SPIDs were higher (greater pain relief) for the ketamine study groups than the control group (standard care 4.0, interquartile range [IQR] = 1.8 to 6.5; group 1 7.0, IQR = 4.3 to 10.8; and group 2 7.8, IQR = 4.8 to 12.8; p < 0.02). The SPIDs for the ketamine groups were similar (p < 0.46). When compared to standard care, group 2 sustained the reduction in pain intensity up to 2 hours, whereas group 1 was similar to standard care by 2 hours. Similar numbers of patients received rescue analgesia: standard care group, seven of 20, 35%; group 1, four of 20, 20%; and group 2, four of 20, 20% (p = 0.48). Among those receiving rescue analgesia, those in the standard care group received analgesia sooner than either low-dose ketamine group, on average. More participants in the low-dose ketamine groups reported dysphoria and dizziness.

CONCLUSIONS: Low-dose ketamine is a viable analgesic adjunct to morphine for the treatment of moderate to severe acute pain. Dosing of 0.3 mg/kg is possibly more effective than 0.15 mg/kg, but may be associated with minor adverse events. Future studies should evaluate additional outcomes, optimum dosing, and use in specific populations.

Full Text Links

Find Full Text Links for this Article

Discussion

You are not logged in. Sign Up or Log In to join the discussion.

Related Papers

Remove bar
Read by QxMD icon Read
25377395
×

Save your favorite articles in one place with a free QxMD account.

×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"