Evidence map›Paper›PMID 30585986›Full record

Trial reportPain2019

An experimental randomized study on the analgesic effects of pharmaceutical-grade cannabis in chronic pain patients with fibromyalgia.

Tine van de Donk, Marieke Niesters, Mikael A Kowal, Erik Olofsen, Albert Dahan, Monique van Velzen

Open access · hybridAbstract readRandomized Controlled Trial
PubMed Full text at PMC Publisher
In one paragraph

Trial report in Pain, 2019. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 120 papers, 9 of them syntheses that pooled it.

0numbers the graph read from it
0cells of the map it votes in
120citing papers in PubMed, 9 pooled it
17.0field-weighted citation impact, top 1% of its field
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

120 citing papers in PubMed, 9 syntheses or guidelines pooled it, 269 citations in OpenAlex.

  1. Guideline
  2. Does acute cannabidiol (CBD) use impair performance? A meta-analysis and comparison with placebo and delta-9-tetrahydrocannabinol (THC).Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology · 2024
    Pooled it
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  10. Trial
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  16. Observational
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  20. The Pro- But Not Antinociceptive Effects of Cannabidiol Depend on Trpa1b in Larval Zebrafish.The Journal of neuroscience : the official journal of the Society for Neuroscience · 2026
    Article

60 more citing papers are in PubMed but not listed here.

4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

6 authors at 1 institution in 1 country.

Tine van de DonkDepartment of Anesthesiology, Leiden University Medical Center, Leiden, the Netherlands.
Marieke NiestersDepartment of Anesthesiology, Leiden University Medical Center, Leiden, the Netherlands.
Mikael A KowalBedrocan International BV, Veendam, the Netherlands.
Erik OlofsenDepartment of Anesthesiology, Leiden University Medical Center, Leiden, the Netherlands.
Albert DahanDepartment of Anesthesiology, Leiden University Medical Center, Leiden, the Netherlands.
Monique van VelzenDepartment of Anesthesiology, Leiden University Medical Center, Leiden, the Netherlands.
Leiden University Medical Center · NL

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

In this experimental randomized placebo-controlled 4-way crossover trial, we explored the analgesic effects of inhaled pharmaceutical-grade cannabis in 20 chronic pain patients with fibromyalgia. We tested 4 different cannabis varieties with exact knowledge on their [INCREMENT]-tetrahydrocannabinol (THC) and cannabidiol (CBD) content: Bedrocan (22.4-mg THC, <1-mg CBD; Bedrocan International BV, Veendam, the Netherlands), Bediol (13.4-mg THC, 17.8-mg CBD; Bedrocan International BV, Veendam, the Netherlands), Bedrolite (18.4-mg CBD, <1-mg THC; Bedrocan International BV, Veendam, the Netherlands), and a placebo variety without any THC or CBD. After a single vapor inhalation, THC and CBD plasma concentrations, pressure and electrical pain thresholds, spontaneous pain scores, and drug high were measured for 3 hours. None of the treatments had an effect greater than placebo on spontaneous or electrical pain responses, although more subjects receiving Bediol displayed a 30% decrease in pain scores compared to placebo (90% vs 55% of patients, P = 0.01), with spontaneous pain scores correlating with the magnitude of drug high (ρ = -0.5, P < 0.001). Cannabis varieties containing THC caused a significant increase in pressure pain threshold relative to placebo (P < 0.01). Cannabidiol inhalation increased THC plasma concentrations but diminished THC-induced analgesic effects, indicative of synergistic pharmacokinetic but antagonistic pharmacodynamic interactions of THC and CBD. This experimental trial shows the complex behavior of inhaled cannabinoids in chronic pain patients with just small analgesic responses after a single inhalation. Further studies are needed to determine long-term treatment effects on spontaneous pain scores, THC-CBD interactions, and the role of psychotropic symptoms on pain relief.

Indexed as

AdultAgedAnalgesicsCannabidiolChronic PainCross-Over StudiesDronabinolFemaleFibromyalgiaHumansMaleMiddle AgedPain MeasurementSurveys and QuestionnairesTime FactorsYoung AdultAnalgesicsCannabidiolDronabinol

Identifiers

PMID30585986
PMCPMC6430597
OpenAlexW2906608791

What OpenQuestion holds

Textmetadata
LicenceCC BY-NC-ND
Read underepoch 390

Registered trials

None linked

Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.