Gingko’s Synergy with Prescribed Medication

Article by Ann Walker

Ginkgo (Ginkgo biloba) trees are sometimes called living fossils – they have thrived on Earth with little genetic change since the time of the dinosaurs, around 200 million years ago. They are tough and resilient trees which survived fallout from the asteroid that extinguished the dinosaurs and from the atomic bomb dropped on Hiroshima in 1945. In China the nuts were used for millennia as medicine for lung complaints, but it is the extracts of the leaves that were developed as medicine in Germany from the 1960s. Ginkgo is the most researched herbal medicine in the world, with attention focused in particular for its benefits as treatment for dementia, memory loss and pain caused by too little blood flow (claudication).

So, it’s good to see increasing evidence coming forward of positive herb-drug interactions (or synergy). This past twelve months, we have seen two examples of synergy in ginkgo studies. The first was a combination of ginkgo with steroids (PMID: 29797955). The forty-two volunteers in the study had lost their sense of smell due to nasal congestion following a viral infection. All received daily steroids, but half of them also took ginkgo extract daily for 3 months. While the sense of smell was improved in all patients, it was improved to a greater extent in the combination group.

The second study was larger, with 136 elderly people with depression (PMID: 30278520). All took the antidepressant citalopram daily but half of them took, in addition, a daily supplement of ginkgo. The combined treatment alleviated depression faster that citalopram alone. Furthermore, the lowering of depression was accompanied by a drop in S100B protein in the bloodstream. S110B is released by ‘housekeeping’ cells in the brain in response to injury and levels are high in depression. In this study, the drop in S100B levels in the combined group was greater than in the citalopram-alone group.

Practitioners of herbal medicine always check the drugs their patients are using/prescribed, to avoid potential herb-drug interactions. Fortunately, proven negative interactions between herbs and drugs in humans are rare, but, even so, the media frequently carries scare stories of adverse interactions based on speculative, rather than proven cases. Often adverse herb-drug interactions cited in the press are based on extrapolated data from laboratory animals fed high levels of the herb, or test-tube studies or just plain guesses. So, it is good to see research reports of positive interactions (synergy) between herbs and drugs.

PMID = PubMed identifier

Ann Walker PhD FCPP MNIMH RNutr
Course Director DHM
Herbal Practitioner