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Does the cannabinoid dronabinol reduce central pain in multiple sclerosis? Randomised double blind placebo controlled crossover trial

BMJ 2004; 329 doi: (Published 29 July 2004) Cite this as: BMJ 2004;329:253
  1. Kristina B Svendsen, research fellow1,
  2. Troels S Jensen, professor1,
  3. Flemming W Bach1 (fbach{at}
  1. 1 Danish Pain Research Center and Department of Neurology, Aarhus University Hospital, Noerrebrogade 44, DK-8000 Aarhus C, Denmark
  1. Correspondence to: F W Bach
  • Accepted 12 May 2004


Objective To evaluate the effect of the oral synthetic δ-9-tetrahydrocannabinol dronabinol on central neuropathic pain in patients with multiple sclerosis.

Design Randomised double blind placebo controlled crossovertrial.

Setting Outpatient clinic, University Hospital of Aarhus, Denmark.

Participants 24 patients aged between 23 and 55 years with multiple sclerosis and central pain.

Intervention Orally administered dronabinol at a maximum doseof 10 mg daily or corresponding placebo for three weeks (15-21days), separated by a three week washout period.

Main outcome measure Median spontaneous pain intensity (numericalrating scale) in the last week of treatment.

Results Median spontaneous pain intensity was significantlylower during dronabinol treatment than during placebo treatment(4.0 (25th to 75th centiles 2.3 to 6.0) v 5.0 (4.0 to 6.4),P = 0.02), and median pain relief score (numerical rating scale)was higher (3.0 (0 to 6.7) v> 0 (0 to 2.3), P = 0.035). Thenumber needed to treat for 50% pain relief was 3.5 (95% confidenceinterval 1.9 to 24.8). On the SF-36 quality of life scale, thetwo items bodily pain and mental health indicated benefits fromactive treatment compared with placebo. The number of patientswith adverse events was higher during active treatment, especiallyin the first week of treatment. The functional ability of themultiple sclerosis patients did not change.

Conclusions Dronabinol has a modest but clinically relevantanalgesic effect on central pain in patients with multiple sclerosis.Adverse events, including dizziness, were more frequent withdronabinol than with placebo during the first week of treatment.


  • Contributors KBS designed the study, collected data, participated in data analyses, and wrote most of the paper. TSJ initiated the study, participated in the design, and contributed to the writing of the paper. FWB initiated the study, participatedin the design, advised on data collection, participated in dataanalyses, and contributed to the writing of the paper. FWB willact as guarantor for the paper. The guarantor accepts full responsibility for the conduct of the study, had access to the data, and controlled the decision to publish.

  • Funding The study was supported by grants from the Danish Multiple Sclerosis Society (grant no 2002/71045), grant 900035 from manager Ejnar Jonasseon and his wife's memorial grant, and the Warwara Larsen Foundation (grant no 664.28), Denmark. Solvay Pharmaceuticals provided study medication (dronabinol (Marinol) and placebo capsules), labelling, and packaging. In addition, the company provided financial support for study monitoring and data analysis. IPC-Nordic, Denmark, packaged and labelled the study medication and monitored the study. These companies were not involved in the design or execution of the study or writing the manuscript.

  • Competing interests None declared.

  • Ethical approval The study was approved by the regional ethics committee (Aarhus,, the Danish Medicines Agency (, and the Danish Data Protection Agency.

  • Accepted 12 May 2004
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