Suh, S.Y., Choi, Y.S., Oh, S.C., Kim, Y.S., Cho, K., Bae, W.K., . . . Ahn, H.Y. (2013). Caffeine as an adjuvant therapy to opioids in cancer pain: A randomized, double-blind, placebo-controlled trial. Journal of Pain and Symptom Management, 46, 474–482.

To assess the efficacy of caffeine infusion as an adjuvant analgesic for patients with advanced cancer on opioids for chronic pain

Patients were randomly assigned to either a caffeine group or a placebo group. The caffeine group was given 200 mg of caffeine intravenously over one hour daily for two days. The placebo group was given normal saline. Pain was assessed before the intervention, one hour after the infusion on day 1, before the intervention on day 2, and one hour after the intervention on day 2.  Adverse events were assessed during interventions and two hours later.

• The study reported on a sample of 38 patients.
• Mean patient age was 65.67 years (SD = 10.88 years).
• The sample was 51.2% female and 48.8% male.
• All patients were receiving palliative care and were not undergoing current treatment. Multiple tumor sites were represented.
• All patients had pain levels of 6 or less on a numeric rating scale.

• Single site 
• Inpatient setting
• South Korea

• Patients were undergoing end-of-life care.
• The study has clinical applicability for palliative care.

A randomized, double-blind, placebo-controlled design was used.

A numeric rating scale (0–10) was used to measure pain and adverse effects.

Pain was significantly lower after the second trial, day 2, in those receiving caffeine (p = 0.038); however, the difference between groups in pain severity decline was extremely small. In those receiving caffeine, the decline in pain scores pre-post day 2 infusion was 0.83 (mean) and in those on placebo, the change was 0.81 (mean).

This study does not provide strong support for efficacy of caffeine infusion as an adjuvant analgesic compared to placebo for patients with pain associated with advanced cancer.

• The study had a small sample, with less than 100 participants.
• There was no analysis of differences in any rescue medication use.

This study does not provide strong evidence for or against the use of caffeine infusions as adjuvant analgesia in patients with pain associated with advanced cancer.