A
digoxin level of 0.9 nanograms/mL was found in a patient taking an un-named herbal remedy, which contained black cohosh root (Cimicifuga racemosa), cayenne pepper fruit (Capsicum annuum), hops flowers (Humulus lupulus), skullcap herb (Scutellaria lateriflora), valerian root (Valeriana officinalis) and wood betony herb (Pedicularis canadensis), all of which contain digoxin-like compounds which are detected by
digoxin antibody immunoassays. Three packaged teas (Breathe Easy, blackcurrant, and jasmine) and 3 herbs (pleurisy root, chaparral, peppermint) have been found, in theory, to provide a therapeutic daily dose of
digoxin, if 5 cups a day are drunk.
It is apparent that if a patient taking
digoxin also consumed these herbal remedies or teas they could develop
symptoms of
digoxin toxicity. However, theoretical interactions with herbal remedies are not always translated into practice. For example, hawthorn is used in cardiac disorders and the leaves and berries are reported to contain digoxin-like substances, but a study in healthy subjects found no pharmacokinetic or pharmacodynamic interaction between
digoxin and an
extract of hawthorn leaves and flowers (Crataegus oxyacantha). Therefore although these predicted interactions should be borne in mind when using
digoxin and herbal remedies they cannot be taken as total proof that an interaction will occur.