Rheumatoid arthritis, cannabis based medicine eases pain and suppresses disease.

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Rheumatoid arthritis, cannabis based medicine eases pain and suppresses

disease.

The first study to use a cannabis-based medicine (CBM) for treating

rheumatoid arthritis has found that it has a significant effect on easing

pain and on suppressing the disease.

Writing in the medical journal Rheumatology [1], the researchers say that

although the differences were small and variable in the group of 56 patients

they studied, the results are statistically significant and a larger trial

is needed to investigate in more detail the effects of CBM on the disease

which affects approximately 600,000 people in the UK (1 in 100 of the

population).[2]

There is anecdotal evidence that cannabis can provide pain relief for people

with rheumatoid arthritis (RA), and in a recent survey 155 (16%) of 947

people who obtained cannabis on the black market for medicinal reasons said

they did so to obtain relief from symptoms of RA. However, this study in

Rheumatology journal, led by Blake, Professor of Bone and Joint

Medicine at the Royal National Hospital for Rheumatic Diseases (RNHRD), Bath

and the University of Bath, UK, is the first randomised controlled trial to

investigate the effect of a CBM on RA. It is published online today

(Wednesday 9 November).

In the double-blind trial, the researchers randomised 31 patients to receive

the CBM and 27 the placebo. The CBM (brand name: Sativex) was in the form of

an easy-to-use mouth spray that patients could administer themselves up to a

maximum of six doses a day. The CBM consisted of a blend of whole plant

extracts, standardised for content, that delivered approximately equal

amounts of two key therapeutic constituents from the cannabis plant:

delta-9-Tetrahydrocannabinol (THC) and cannabidiol (CBD). Mouse studies have

shown that THC and CBD have anti-inflammatory effects, and that CBD blocked

progression of RA and produced improvements in symptoms.

Dr Jubb, Consultant Rheumatologist, at the University Hospital

Birmingham NHS Foundation Trust, UK, said: " Patients had a baseline

assessment at the beginning of the trial and then were randomised to receive

either the CBM or placebo. Patients only took the doses in the evening in

order to minimise possible intoxication-type reactions. The starting dose

was one actuation within half an hour of retiring, and this was increased by

one actuation every two days to a maximum of six doses according to

individual response over a period of two weeks. Stable dosing was then

maintained for a further three weeks. "

The researchers found that in comparison with the placebo, patients who had

taken the CBM had statistically significant improvements in pain on movement

pain at rest, quality of sleep, inflammation (measured by a Disease

Activity Score involving 28 joints - DAS 28) and intensity of pain (measured

by the Short-Form McGill Pain Questionnaire SF-MPQ).

For instance, on a score of 0-10 where 0 is no pain, CBM patients on average

moved from 7 to 4.8 for pain on movement (placebo patients moved from 6.7 to

5.3), 5.3 to 3.1 (placebo 5.3 to 4.1) for pain at rest, and 5.7 to 3.4

(placebo 5.8 to 4.6) for quality of sleep. On the DAS 28 score of 0-10, the

CBM patients moved from 5.9 to 5 (placebo 6 to 5.9), and on the SF-MPQ score

of 0-100 for intensity of pain at present, the CBM patients moved from 48 to

33, while the placebo patients remained unchanged at 50.

Adverse side effects were mostly mild or moderate (e.G. Dizziness,

light-headedness, dry mouth, nausea). Of the eight patients who experienced

mild dizziness, in four patients this occurred during the initial two-week

period when they were gradually increasing the doses, and two occurred two

days after this initial period, so these were probably due to patients

getting used to the correct dose. No patients taking the CBM had to withdraw

from the trial due to adverse side effects, but three did from the placebo

group.

Dr Philip Robson, Senior Research Fellow and Consultant Psychiatrist at the

Oxford University Department of Psychiatry and Director of the Cannabinoid

Research Institute within GW Pharmaceuticals (the manufacturer of Sativex),

explained: " Withdrawals from the placebo group were probably due to a

psychological effect, a spontaneous occurrence, or a reaction with another

medicine. "

Dr Jubb said: " The results from the first controlled study of CBM in

rheumatoid arthritis are encouraging, with overall improvements in pain on

movement and at rest, improvement in the quality of sleep and improvement in

the overall condition of the patients' arthritis. Whilst the differences are

small and variable across the patient group, they represent benefits of

clinical relevance and indicate the need for more detailed investigation

through larger trials to see exactly where CBM could be best used with

minimum side effects. "

If further trials are run, researchers will probably extend the dosing

period over the full 24-hour period. Dr Robson said: " The beneficial effects

in this study occurred in the context of a dosing regime restricted to

evening dosing in order to minimise any possible intoxication-type reactions

However, 24-hour dosing with Sativex, using a self-titration regime, in

trials for multiple sclerosis resulted in only minimal intoxication scores. "

He continued: " The element that can cause the 'high' in cannabis - THC -

also has valuable pharmacological activity. It is thought to be an essential

therapeutic component and therefore it can't be removed from the medicine.

However, the method of giving the doses, via the mouth spray, and the

principle of self-titration, where each patient gradually determined their

own optimal dose level up to a maximum of six doses a day, minimised the

risk of intoxication. "

Dr Robson said that fears that the CBM could be abused by patients hoping to

get a " high " were probably unfounded. " It seems that in practice this is a

very rare event. More than 1,000-patient years of treatment with Sativex in

clinical trials have been accumulated and to date there has not been a

single documented case of abuse. The fact is that the motivation of

medicinal users of cannabis-based medicine is entirely different from

recreational users: the former simply want symptom relief and the ability to

go about their normal lives, and for them intoxication would be a distinct

disadvantage; for the latter, smoking marijuana is infinitely more

intoxicating than Sativex and is still easily available. "

[1] Preliminary assessment of the efficacy, tolerability and safety of a

cannabis-based medicine (Sativex) in the treatment of pain caused by

rheumatoid arthritis. Rheumatology Advance Access published on November 9,

2005.

doi:10.1093/rheumatology/kei183

[2] Rheumatoid arthritis affects three times as many women as men. Prevalence in

the UK is approximately 0.5% in men and 1.8% in women, increasing after the age

of 64 to 2% in men and 5% in women. There are many more people with less severe

forms of RA that do not meet the diagnostic criteria for definite or classical

disease.