Herbal medicines are preparations that contain plants or parts of plants, whether in the crude or processed state, and claim therapeutic or prophylactic properties. They are available as modern drug preparations like drops, tablets, dragées and capsules, and also as traditional preparations like herbal teas. The concept of efficacy in phytotherapy is based on the mixture of substances contained in the medicinal plant. Preparations of a single plant, as well as combinations of two or more plants, are available on the market.
RELEVANCE IN THE EUROPEAN MARKET
Herbal preparations have a long history as medicinal products and some are known to be effective and safe drugs. During the past decades, public interest in herbal medicines has increased due to the trend towards natural sources and to a healthy lifestyle. Therefore, the market share of herbal medicines in the pharmaceutical market has steadily increased during the last decade. Herbal medicines are available in all European countries, although their importance varies considerably from one country to another. Germany and France alone account for approximately 75% of the herbal medicine sales in Europe. In 2000, approximately 30% of the over-the-counter drugs (OTC drugs) sold in German pharmacies were herbal medicines.
REGULATORY ASPECTS
- Due to their complex composition and their natural origin, some peculiarities of herbal medicines regarding the assessment of quality, safety, and efficacy have to be considered:
- The raw materials are not homogenous; the amount and quality of active ingredients can vary due to different cultivation and harvesting methods; quality assurance has to start with the cultivation of raw materials.
- Not only the main active ingredients are important, the accompanying substances may influence the bioavailability and efficacy considerably; herbal drugs are effective due to their complex combination.
- The method of manufacturing decisively influences the composition of the herbal drug.
Many herbal medicines have a high safety margin with respect to possible health risks (broad therapeutic window; low risk of side effects and interactions). On the other hand interactions have been reported (St. John's wort) with other drugs, and some preparations have been removed from the market due to hepatotoxic risks/reactions (kava kava).
However, if a new herbal preparation claims therapeutic or prophylactic benefits, then safety, efficacy and quality data comparable to the requirements for a chemical entity are mandatory for marketing authorisation. These data may be provided in the form of pharmacological, toxicological and clinical studies, or by means of other scientific knowledge as for example monographs, medical experience reports, and relevant literature. The compilation of this scientific knowledge is supported by several organisations. The ESCOP (European Scientific Co-operation on Phytotherapy) prepares monographs on the medicinal uses of plant drugs on the basis of published information. These monographs are submitted to the EMEA (European Agency for the Evaluation of Medicinal Products) as proposals for core-SPC (Summary of Product Characteristics) documents.
The Herbal Medicinal Products Working Party of the EMEA aims to facilitate the Mutual Recognition Procedure for herbal medicines by providing guidance for authorities and applicants and developing new guidance for the evaluation of quality, safety, and efficacy of herbal medicines. In Germany, the Commission E of the BfArM (Federal Institute for Drugs and Medical Devices) prepared monographs for 330 medicinal plants up to 1994. These monographs are now maintained by the German "Kooperation Phytopharmaka".
HERBAL MEDICINES CAN BE DIVIDED INTO THREE CATEGORIES:
1. New entities: plants or preparations of plants that had no medicinal use so far or that claim a new indication are subject to the same requirements as new chemical entities in respect of the assessment of quality, safety, and efficacy. This can include also a new extraction procedure for known herbals.
2. Well-established use: for plants and preparation of plants with well-documen-ted safety and efficacy data in the claimed indication, an abridged application can be submitted.
3. Traditional use: for certain indications, safety and efficacy is assumed for plants and preparation of plants with a long experience (30 years at least).
In all three categories, full quality documentation has to be submitted.
As the European Mutual Recognition Procedure assumes greater importance, harmonisation of the requirements for the evaluation of herbal medicines by the relevant European authorities becomes a major objective. However, the national regulations for herbal medicines in the individual European member states differ significantly.
SITUATION IN SWITZERLAND
Of 7,890 drugs registered at the Swiss authority, Swissmedic, in 2001, 971 (12.3%) were herbal drugs.
Since 2002, all herbal medicines, with a few exceptions, have to be registered at Swissmedic (HMG, Art. 9). Especially for small companies in the business of herbal medicines, this represents a considerable effort. Therefore, an abbreviated application is provided for complementary and herbal medicines (HMG, Art. 14; VAZV, Art. 1).
With an abbreviated application, the following documents have to be submitted to demonstrate safety and efficacy of the drug:
- Proof of therapeutic equivalence to an approved drug
- Documented medical experience and case reports
- Bibliographic documentation if the results are assignable to the drug (VAZA Art. 9)
For new substances and new indications, a full documentation including preclinical and clinical studies is necessary. A bibliographic documentation may be sufficient if no new indication is claimed. If no adequate bibliographic data are available, new studies have to be conducted in any case. Comprehensive guidance for the marketing application of complementary and herbal medicines in Switzerland has still to be elaborated.
- The authors are with RCC Ltd