Quotation from the draft document issued by the German Federal Institute for Drugs and Medical Devices (BfArM) "Assessment of possible pharmacokinetic interactions between medicinal products and herbal drugs"
(available in German language):
With regard to clinical data, Directive 2001/83/EC, Annex I, stipulates:
"If the medicinal product is normally to be administered concomitantly with other medicinal products, particulars shall be given of joint administration tests performed to demonstrate possible modification of the pharmacological action.
Pharmacokinetic interactions between the active substance and other medicinal products or substances shall be investigated."
On this basis, investigations or bibliographic data on interactions are also to be requested as soon as elder, multi-morbid patients are involved who often take more than one medicinal product. Among others, this fact is applicable for hawthorn preparations in the indication "declining cardiac performance corresponding to NYHA II".