Rhei rhizoma
Rhei rhizoma contains sennosides that are prodrugs of rhein-anthrone,
having cathartic activity. Therefore R.rhizomais not suitable to give to
patients who have hypofunctional symptoms.
Drug–drug interactions
Some western medicines are known to have potent adverse reactions, e.g.
antitumour agents generally cause anaemia, decrease of leukocytes, and
cause systemic weakness and vomiting. The use of western medicine with
kampo medicines classified as tonic, such as Juzentaihoto,Hochuekkito,
NinjinyoeitoandRikkunshito, can reduce the adverse reaction to western
anticancer drugs in patients and increase their quality of life. As one mech-
anism of action, it has been reported that Juzentaihotoenhances the prolif-
eration of haematopoietic stem cells, and recovery of the haematopoietic
system. Steroids also have side effects such as moon face (swelling),
thrombus, infection and menopausal disorders.
Kampo medicines, such as Shosaikoto, Saireito and Saibokuto, can
reduce these adverse reactions. It is also possible to decrease the daily dose
of steroid and even to stop its use. It has been reported that these kampo
medicines increase endogenous corticosterone concentrations in the body by
affecting steroid metabolism.
It is known that several glycosides in kampo medicines show various
biological activities as prodrugs, and aglycones, which are produced by the
action of glycosidases from intestinal bacteria, can be absorbed into the
blood and be active. Therefore, it is possible that some antibiotics may kill
bacteria and affect the actions of kampo medicines when both are given
together. As kampo medicines are very popular in Japan, drug interactions
between kampo medicines and western medicine should be considered in
order to avoid an undesired change in the efficacy.
Availability of kampo medicines
The first six kampo extract pharmaceutical preparations were developed in
granule form in 1957. Since 1976, 147 kampo granular or powder formu-
lations and one ointment have been approved for reimbursement by the
Japanese national health insurance system. Their acceptance was based on
clinical experience of efficacy and safety without any clinical validation
studies. Herbs that are components of such kampo formulations are also
covered by insurance.
In 1965, the Ministry of Health and Welfare of Japan designated 210
kampo formulations as over-the-counter drugs, chosen on the basis of
Japanese kampo medicine | 247