This drug works, this one doesn't; this herb is good, no, it's badDrug/herb safety and effectiveness is a complicated issue
With conflicting news on drugs and herbs daily, it is getting really confusing for consumers to pick what is good for them. Results from clinical trials and observational studies are published daily and there is more confusion.
Clinical trials are research studies involving people. They test whether particular treatments are safe and how well they work. We need to know: Does a treatment work? Does it work better than other treatments? Does it have any side effects? Clinical trials are designed to answer these questions and improve health and quality of life for patients. Until well-designed trials have been carried out, we simply do not have enough evidence to know if a treatment is both effective and safe.
Clinical trials constitute the gold standard to assess the efficacy and safety of new medicines. However, because they are conducted in standardized conditions far from the real world of prescription and use, discrepancies in patient selection or treatment conditions may alter both the effectiveness and risks. Postmarketing surveillance of a drug can further refine, or confirm or deny, the safety of a drug after it is used in the general population by large numbers of people who have a wide variety of medical conditions.
The basic idea behind observational studies is to examine groups of people or patients for exposures and associate the results with a disease outcome. The problem is that there may be factors of importance which are either unknown or poorly understood. The possibility of hidden bias may cause the analysis to provide a false result.
To help simplify and summarize clinical trial data for practitioners, researchers conduct and publish meta-analyses of research. A meta-analysis is a statistical review of multiple clinical trials, as single studies are often insufficient for providing definitive answers to clinical questions.
While recognizing the value of meta-analyses in medical literature, it is important to point out one potentially serious problem with this approach in the field of herbal medicine - the "pooling" of different products to reach a conclusion about one particular herb.
When comparing products that differ in extraction technique, plant part, delivery system and dose, it makes the question of equivalency a very valid one. So when one conducts a systematic review or meta-analysis of all echinacea clinical trials, what does the conclusion mean when the pooled studies include products containing Echinacea purpurea fresh pressed juice from the aerial parts of the plant, Echinacea purpurea root, Echinacea pallida root, Echinacea angustifolia root, or any combination thereof, using different solvents in differing doses?
Evaluating these products from an analytical perspective, there is a definite difference between E. purpurea fresh pressed juice and E. pallida dried root, When the conclusion makes broad, sweeping statements such as "Herb x has not shown to be effective in a review of the clinical trials," it must be called into question if the review is lumping together different products.
A fundamental principle of any experiment is that the larger the number of subjects, the smaller the margin of error and the greater the confidence in the outcome of the study. Small studies generally have large uncertainties in results unless the effect of the intervention is very pronounced. Because there are so many companies making the same herbal preparation, no one wants to invest to do a large trial. It is understandable that many healthcare providers and consumers believe that one herbal product can simply be substituted for another; however, in some situations it may be important to ask if two products manufactured by two different companies have biological and pharmaceutical equivalence.
According to the United States pharmacopeia, two products are pharmaceutically equivalent if they contain the same active ingredient, are in the same dosage form, and use the same route of administration, and if the label states the same conditions of use.
This is pretty straightforward for single-ingredient products such as acetaminophen or aspirin, which is why one can expect the same effects from a generic or branded product. This is sometimes not true, though; many patients who have been stable on a branded product for years fail to respond to an equivalent generic. Pharmaceutical equivalency gets tricky when dealing with complex substances such as botanicals. Good research reporting should include the source of the plant material, whether it is fresh, dried or baked, extracted with alcohol or some other solvent, the ratio of the plant material to the final extract as well as any chemical standardization and formulation details in the published reports.
Dosing in herbal products is another problem. What is the optimal dose for a particular herb or herbal product? There is very little consistency in dose across the myriad of products found in the marketplace. This leaves consumers confused about how much to take, practitioners confused about how much to recommend and researchers confused about how much to study
I think the biggest problem with evaluating the efficacy and safety of herbal products is a lack of understanding of what it takes to characterize an herbal preparation. Synthetic, single-entity drugs are relatively easy to characterize, as they are usually single chemicals. Herbal preparations, on the other hand, are very complex, containing hundreds of compounds. Many conventional healthcare practitioners don't realize that it is not enough just to provide the name of the botanical, i.e., garlic or echinacea. As an example, there are many different preparations of garlic: dried garlic, aged garlic, garlic oil, etc. These different garlic preparations have different chemical profiles. And, in addition to the chemical composition, the formulation is also important for therapeutic effect. Some products may dissolve easily in the stomach and digestive system, while others may not.
Sometimes the clinical trials are not able to answer questions, because every individual is different. Researchers are coming to understand just how individualized human physiology and human pathology really are. On a genetic level, the tumors in one person with cancer may not be identical to those of any other. Even in a more widespread condition like high cholesterol, the variability between individuals can be great, meaning that any two patients may have starkly different reactions to a drug.
So what should be done? I think the best approach is to personalize the treatment plan. Patient and the physician partner together and review the literature and pick the best option for the patient, keeping in mind his/her conditions and other drugs and herbs in use. It is not as simple as some people think, picking up an herb from the shelf after reading about it on the internet or watching something on TV. The same is true regarding stopping a drug after looking at the commercials on TV. It is always a great choice to go and discuss it with your physician because he/she will be able to guide you through the maze of medical literature.
Uday Jani, MD, FACP, is board certified in internal medicine and fellowship trained in integrative medicine. He practices at Shore View Medical P.A., 28312 Lewes-Georgetown Highway, Milton, 302-684-0990.