This summary of a Cochrane review presents what we know from research about the effects of herbal therapy for rheumatoid arthritis (RA).
The review shows that in people with RA:
- Evening primrose oil, borage seed oil, or blackcurrent seed oil (containing gamma-linolenic acid (GLA)) probably improve pain; may improve function; and probably does not increase adverse events (unwanted side effects).
- Tripterygium wilfordii Hook F may improve some symptoms of rheumatoid arthritis, and higher doses (180 mg - 350 mg daily) may be more effective than lower doses (60 mg daily). There are some adverse events associated with Tripterygium wilfordii Hook F.
- We are uncertain of the effects of other herbal therapies because only single studies were available, or important features of RA, such as changes in the number of swollen and tender joints, were not reported.
Often we do not have precise information about side effects and complications, particularly for rare but serious side effects. Possible side effects associated with Triperygium wilfordii Hook F may include painful periods in women, decreased fertility in men, insufficient urine excretion, and increased rate of infections. Possible side effects associated with GLA sourced from evening primrose oil include headache, nausea, and diarrhoea, and rare complications include allergy and seizures.
What is rheumatoid arthritis and what is herbal therapy?
When you have RA, your immune system, which normally fights infection, attacks the lining of your joints. This makes your joints swollen, stiff and painful. The small joints of your hands and feet are usually affected first. There is no cure for rheumatoid arthritis at present, so treatments are used to relieve pain and stiffness and improve your ability to move.
Herbal interventions are defined as any plant preparation (whole, powder, extract, standardised mixture) used for medicinal purposes. Historically, many herbal therapies have been used to treat RA. Like conventional non-herbal drugs, many herbal therapies are believed to act by blocking the activity of these immune cells and substances and reducing inflammation in the joints, and some people believe they have fewer side effects.
Best estimate of what happens to people with rheumatoid arthritis:
Pain (higher scores mean worse or more severe pain):
-People who took eveing primrose oil, primrose oil, borage seed oil, or blackcurrent seed oil (wih the active ingredient GLA) rated their pain to be 33 points lower (9 to 56 points lower) on a scale of 0 to 100 after 6 months of treatment (33% absolute improvement).
-People who took placebo rated their pain to be 19 points lower after treatment.
Physical function (higher score means greater disability):
-People who took GLA rated their disability 16% better.
-People who placebo rated their disability 5% better.
Several herbal interventions are inadequately justified by single studies or non-comparable studies in the treatment of rheumatoid arthritis. There is moderate evidence that oils containing GLA (evening primrose, borage, or blackcurrant seed oil) afford some benefit in relieving symptoms for RA, while evidence for Phytodolor® N is less convincing.Tripterygium wilfordii products may reduce some RA symptoms, however, oral use may be associated with several side effects. Many trials of herbal therapies are hampered by research design flaws and inadequate reporting. Further investigation of each herbal therapy is warranted, particularly via well designed, fully powered, confirmatory clinical trials that use American College of Rheumatology improvement criteria to measure outcomes and report results according to CONSORT guidelines.
Herbal medicine interventions have been identified as having potential benefit in the treatment of rheumatoid arthritis (RA).
To update an existing systematic (Cochrane) review of herbal therapies in RA.
We searched electronic databases Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library), MEDLINE, EMBASE, AMED, CINAHL, Web of Science, Dissertation Abstracts (1996 to 2009), unrestricted by language, and the WHO International Clinical Trials Registry Platform in October 2010.
Randomised controlled trials of herbal interventions compared with placebo or active controls in RA.
Two authors selected trials for inclusion, assessed risk of bias and extracted data.
Twelve new studies were added to the update, a total of 22 studies were included.
Evidence from seven studies indicate potential benefits of gamma linolenic acid (GLA) from evening primrose oil, borage seed oil, or blackcurrent seed oil, in terms of reduced pain intensity (mean difference (MD) -32.83 points, 95% confidence interval (CI) -56.25 to -9.42,100 point pain scale); improved disability (MD -15.75% 95% CI -27.06 to -4.44%); and an increase in adverse events (GLA 20% versus placebo 3%), that was not statistically different (relative risk 4.24, 95% CI 0.78 to 22.99).
Three studies compared Tripterygium wilfordii (thunder god vine) to placebo and one to sulfasalazine and indicated improvements in some outcomes, but data could not be pooled due to differing interventions, comparisons and outcomes. One study reported serious side effects with oral Tripterygium wilfordii Hook F. In the follow-up studies, all side effects were mild to moderate and resolved after the intervention ceased. Two studies compared Phytodolor® N to placebo but poor reporting limited data extraction. The remaining studies each considered differing herbal interventions.