Open-label trial compared cannabis, oxycodone, and their combination for fibromyalgia pain | Research

The takeaway

In a proof-of-concept trial, pharmaceutical-grade cannabis and its combination with oxycodone were tested against oxycodone alone for fibromyalgia, exploring whether cannabis could enable lower opioid doses.

Pain medicine clinicians, opioid prescribers, fibromyalgia patients, and researchers studying cannabis-opioid interactions.

First trial directly comparing cannabis, opioid, and combination therapy for fibromyalgia

What the researchers found

The SPIRAL study randomized fibromyalgia patients to three arms: cannabis alone, oxycodone alone, or cannabis+oxycodone combination. The trial examined whether combining cannabis with opioids could maintain pain relief while reducing opioid consumption.

Why it matters

If cannabis can allow lower opioid doses while maintaining pain control, it could reduce opioid-related harms in chronic pain populations. This is the first trial directly testing this combination approach in fibromyalgia.

The numbers in context

Three treatment arms: cannabis alone, oxycodone alone, cannabis+oxycodone combination. Pharmaceutical-grade cannabis used. Proof-of-concept design.

How the study worked

Single-center, randomized, three-arm, open-label, proof-of-concept study. Fibromyalgia patients randomized to pharmaceutical-grade cannabis, oxycodone, or cannabis/oxycodone combination.

What this study cannot tell us

Open-label design introduces significant expectation bias. Single-center. Proof-of-concept with likely small sample. Fibromyalgia results may not generalize to other chronic pain conditions. Pharmaceutical-grade cannabis may not reflect commercial products.

How to read the evidence

Randomized but open-label proof-of-concept trial. Important first step but expectation bias and small scale limit conclusions.

When this study was published

Published 2023.

The bigger picture

The opioid-sparing potential of cannabis is frequently discussed but rarely tested in controlled trials. This study directly addresses whether combining the two produces better outcomes than either alone in a chronic pain population.

Questions still open

Would a double-blind trial confirm these preliminary findings? What is the optimal cannabis-opioid dose ratio for pain relief with minimal side effects?

Common questions

Can cannabis replace opioids for pain?

This trial tested that question directly by comparing cannabis alone, oxycodone alone, and their combination for fibromyalgia. While the proof-of-concept design provides preliminary data, the open-label format means patients knew what they were receiving, which can significantly influence pain perception and reporting.

Is it safe to combine cannabis and opioids?

Some research suggests cannabis and opioids may have complementary pain-relieving mechanisms. However, both substances affect cognitive function and sedation. Any combination approach requires careful medical supervision and monitoring for additive side effects.

Read the original research

Cannabis-opioid interaction in the treatment of fibromyalgia pain: an open-label, proof of concept study with randomization between treatment groups: cannabis, oxycodone or cannabis/oxycodone combination-the SPIRAL study.

Trials, 24(1), 64

View on PubMed ↗Publisher’s paper ↗

Citation

van Dam, Cornelis Jan; van Velzen, Monique; Kramers, Cornelis; Schellekens, Arnt; Olofsen, Erik; Niesters, Marieke; Dahan, Albert. (2023). Cannabis-opioid interaction in the treatment of fibromyalgia pain: an open-label, proof of concept study with randomization between treatment groups: cannabis, oxycodone or cannabis/oxycodone combination-the SPIRAL study.. Trials, 24(1), 64. https://doi.org/10.1186/s13063-023-07078-6