A comprehensive review of herbal medicine products in the latest issue of the Drug and Therapeutics Bulletin (DTB) shows that there is little conclusive evidence to justify the widespread use of herbal medicines to relieve the symptoms of the painful joint condition osteoarthritis.
The products involved contain devil’s claw and recently, the UK drug regulator, the Medicines and Healthcare products Regulatory Agency (MHRA), has approved several of these products under the Traditional Herbal Registrations scheme. According to the DTB, the trial results for devil’s claw “are equivocal.”
It is estimated that approximately 8.5 million individuals in the UK suffer from joint pain and other symptoms that are potentially caused by osteoarthritis, which is also known as degenerative arthritis or degenerative joint disease. Osteoarthritis is caused by ageing or wear and tear to the joints, usually the knees or hips and finger, and involves damage to cartilage and other structures in and around the joints.
Various vegetable extracts and herbs have traditionally been used in Herbal medicine for the treatment of osteoarthritis, such as devil’s claw, cat’s claw, ginger, rosehip, Indian frankincense, willow bark, nettleturmeric and vegetable extracts from avocado or soybean oils (ASUs).
The DTB warns that few studies have been conducted on using herbal medicines for osteoarthritis. Previous studies frequently demonstrate limitations and design flaws like differences in the chemical make-up of the same herb, and therefore compromise the validity of any results. In addition, the DTB says, these studies were conducted in insufficient numbers of patients and were too short, which for long-term conditions, such as osteoarthritis, is of particular importance.
According to the DTB, current clinical trial evidence suggests that the ASUs Rosehip and Indian frankincense potentially work, and appear to bring on few unwanted side effects, however they add that: “More robust data are needed.”
The DTB state that: ‘evidence in favor of their use is at best equivocal or unconvincing’ in terms of the remaining ASUs, and points out that Herbal drugs can also interfere with other medicinal products and prescription drugs.
It also states:
“Herbal medicines can have significant pharmacological actions, and so can cause unwanted effects and have potentially dangerous interactions with other medicines (both herbal and conventional).”
For example, the DTB announces that extensive use of nettle can interfere with diabetes drugs and medicine for treating lower blood pressure by depressing the central nervous system. Whilst Willow bark can trigger digestive symptoms and renal problems, some herbal drugs can potentially worsen the symptoms of other underlying conditions. Cat’s claw and nettle should not be used during pregnancy, and willow bark is not recommended for those suffering from asthma, peptic ulcers, or anyone with clotting disorders.
The DTB concludes that:
“Herbal medicines have traditionally been used for the relief of osteoarthritis symptoms. However, there is a lack of licensed herbal medicinal products on the market for such symptoms, and none specifically licensed for osteoarthritis. Also the efficacy and safety of such products is generally under researched and information on potentially significant herb-drug interactions is limited.”
It advises doctors to routinely ask their patients with osteoarthritis if they are taking any herbal products.
Written by Petra Rattue