Ginkgo biloba: Contraindications. Practice Points. FAQ

Contraindications and Precautions If unusual bleeding or bruising occurs, stop use immediately. Although new clinical evidence suggests that Ginkgo biloba does not affect clotting times, it may be prudent to suspend use for 1 week prior to major surgery. CEREBRAL HAEMORRHAGE AND EPILEPSY Recent, rare case reports have suggested that ginkgo should be used with caution in people with known risk factors for cerebral haemorrhage and epilepsy until further investigation can clarify its safety. Pregnancy Use Not recommended in pregnancy as insufficient reliable evidence is available to determine safety. Practice Points / Patient Counselling • Ginkgo biloba is a complex herb that contains many different active constituents and works by means of multiple mechanisms. Therefore, it has applications in many varied conditions. • It is an effective treatment in conditions of acquired cognitive impairment, including dementia of any degree of severity and intermittent claudication, according to evidence from meta-analyses. • Positive evidence also exists for premenstrual syndrome, sudden deafness, Raynaud’s syndrome and depression when associated with cognitive decline. • Largely based on the herb’s physiological Read more […]

Ginkgo biloba: Significant Interactions

PLATELET INHIBITOR DRUGS Due to its platelet-activating factor antagonist activity, Ginkgo biloba may theoretically enhance the effects of these drugs and increase risk of bruising or bleeding; however, three clinical trials have cast doubt on the clinical significance of this activity — observe patients taking this combination. WARFARIN Theoretically, ginkgo may increase bleeding risk when used together with warfarin; however, two randomised double-blind studies have found that Ginkgo biloba does not affect the pharmacokinetics, pharmacodynamics, INR or clinical effects of warfarin, and two clinical trials have not found evidence of significant effects on bleeding. Due to the potential seriousness of such an interaction, caution is still advised. CHOUNERGIC DRUGS Cholinergic activity has been identified for ginkgo; therefore, combined use may theoretically increase drug activity — observe patients using this combination, although the effects may be beneficial when used under supervision. DOXORUBICIN In vivo research suggests that ginkgo can prevent doxorubicin-induced cardiotoxicity suggesting a potentially beneficial interaction, although no human studies are available to confirm clinical significance. ANTIDEPRESSANT Read more […]

Ginkgo biloba: Uses. Dosage. Adverse Reactions

Other Uses Ginkgo biloba is used for many other indications, including improving connective tissue conditions such as haemorrhoids, common allergies, reducing the effects of exposure to radiation and to prevent some of the complications associated with diabetes. In the UK and other European countries, the cardioprotective effects of EGb 751 in myocardial ischaemia and reperfusion are currently being investigated in preclinical studies. ADJUNCT IN CANCER TREATMENT As a herb with significant antioxidant activity, ginkgo has been used to reduce the toxic side-effects of some chemotherapeutic drugs. Evidence from in vivo studies demonstrate protective effects against nephrotoxicity induced by cisplatin and cardiotoxicity induced by doxorubicin. Clinical trials are not yet available to determine its effectiveness in practice. CANCER PREVENTION A 2005 review puts forward the case that Ginkgo biloba should be more widely used as a safe, preventative agent for reducing cancer incidence. This recommendation is based on results from numerous in vitro and experimental studies showing that ginkgo affects many factors associated with the incidence and mortality of cancer. Dosage Range The recommended dose varies depending Read more […]

Ginkgo biloba: Clinical Use

Ginkgo biloba is a complex herb that contains many different active constituents and works by means of multiple mechanisms. In practice, its therapeutic effect is a result of interactions between constituents and mechanisms, giving it applications in many varied conditions. To date, most of the research conducted in Europe has used a standardised preparation known as EGb 761, available commercially as Rokan, Tanakan or Tebonin. DEMENTIA, MEMORY IMPAIRMENT Ginkgo biloba has been used and studied as a cognitive activator in a variety of populations, such as cognitively intact people, those with cerebral insufficiency, age-related memory impairment, Alzheimer’s dementia or multi-infarct dementia. A 2002 Cochrane review of the scientific literature concluded that Ginkgo biloba produces benefits superior to placebo within 12 weeks’ treatment in people with acquired cognitive impairment, including dementia, of any degree of severity. Cognition, activities of daily living and measures of mood and emotional function show significant benefit for ginkgo compared with placebo. Some clinical studies have also found that EGb 761 improves the capacity of geriatric patients to cope with the stressful demands of daily life. Clinical Read more […]

Ginkgo biloba: Background. Actions

Historical Note Ginkgo biloba is one of the world’s oldest living tree species, earning it the name ‘living fossil’. Its existence can be traced back more than 200 million years and it was commonly found in North America and Europe before the Ice Age. Ginkgo was first introduced into Europe in 1690 by the botanist Engelbert Kaempfer, who described it as the ‘tree with duck feet’. Ginkgo has been used medicinally for many centuries and is now one of the most popular therapeutic agents prescribed in Europe by medical doctors. It has been estimated that in Germany and France, prescriptions for ginkgo make up 1% and 1.3%, respectively, of total prescription sales. Also popular in the United States, it was the top selling herbal medicine in 1999 with sales of US$148 million. Common Name Ginkgo Other Names Adiantifolia, Arbre aux quarante ecus, bai guo ye, duck foot tree, fossil tree, gin-nan, icho, Japanese silver apricot, kew tree, maidenhair tree, salisburia, silver apricot, tempeltrae, temple balm, yinhsing Botanical Name / Family Ginkgo biloba (family Ginkgoaceae) Plant Parts Used In modern times the leaf is used, but traditionally the nut was also used. Chemical Components Important constituents present in Read more […]

Licorice: Practice Points – Patient Counselling. FAQ

Contraindications and Precautions Licorice should be used with caution in people with hypertension (or a genetic predisposition to hypertension) or fluid retention, and is contraindicated in hypotonia, severe renal insufficiency, hypokalaemia, liver cirrhosis and cholestatic liver disease. The effects are likely to be dose-dependent and more likely in people with essential hypertension with a particular tendency to 11HSD inhibition by licorice. It is also contraindicated in people with a deficiency in 11HSD. Long-term use (>2 weeks) at therapeutic doses should be monitored closely due to the potential side-effects. Additionally, a high-potassium low-sodium diet should be consumed during treatment. As licorice may questionably reduce testosterone levels in men, it should be used with caution in men with a history of impotence, infertility or decreased libido. Pregnancy Use Licorice is contraindicated in pregnancy. A Finnish trial found that high consumption of licorice during pregnancy increased the likelihood of early delivery but did not significantly affect birth weight or maternal blood pressure. Practice Points / Patient Counselling • Licorice has been used as a food, flavouring agent and medicine Read more […]

Licorice: Significant Interactions

Controlled trials exist that have identified drug interactions. However, in most cases, the interactions are based on evidence of pharmacological activity, case reports or theoretical reasoning. The deglycyrrhizinated licorice form is considered safer and less likely to result in drug interactions. ANTICOAGULANTS Isoliquiritigenin inhibits platelet aggregation and glycyrrhizin inhibits prothrombin according to in vitro and in vivo tests. Whether the effect is clinically significant for licorice remains to be determined — use high doses with caution. ANTIHYPERTENSIVES High-dose glycyrrhizin taken long term can lead to increased blood pressure, thereby reducing drug efficacy. Caution — monitor blood pressure when high-dose licorice preparations are taken for longer than 2 weeks. CHEMOTHERAPY (PACLITAXEL AND VINBLASTINE) A constituent of licorice has demonstrated significant potentiation of paclitaxel and vinblastine chemotherapy in vitro. Observe — beneficial interaction is theoretically possible under medical supervision. CORTICOSTEROIDS Concurrent use of licorice preparations potentiates the effects of topical and oral corticosteroids (e.g. prednisolone). Some practitioners employ licorice to minimise Read more […]

Licorice: Adverse Reactions

Many of the adverse effects attributed to licorice are due to glycyrrhetinic acid (GA) at doses above 100-400 mg/day. For this reason, the deglycyrrhizinated licorice (DGL) may be safer and more appropriate in cases where glycyrrhizin (GL) or GA are not required for efficacy. Side-effects may be more pronounced in people with essential hypertension who appear to be more sensitive to the inhibition of 11HSD by licorice than normotensive subjects. • Hypercortisolism and pseudohyperaldosteronism — associated with sodium retention, potassium loss and suppression of the renin-angiotensin-aldosterone system and presenting as hypertension, fluid retention, breathlessness, hypernatraemia and hypokalaemia. • Hypokalaemia — may present as hypotonia and flaccid paralysis, peripheral oedema, polyuria, proximal myopathy, lethargy, paraesthesiae, muscle cramps, headaches, tetany, breathlessness and hypertension. In practice, licorice is often mixed with the potassium-rich herb dandelion leaf, which also has mild diuretic effects. • Hypokalaemic paralysis — although rare, some cases have been reported as a result of chronic licorice use. • Rhabdomyolysis — a number of cases are reported in the scientific Read more […]

Licorice: Clinical Use. Dosage

PEPTIC ULCER AND DYSPEPSIA The anti-inflammatory, mucoprotective and anti-ulcer activities of licorice make it an attractive treatment for peptic ulcer. While these effects have been attributed to the glycyrrhizin (GL) and glycyrrhetinic acid (GA) constituents, the deglycyrrhizinated licorice (DGL), which contains <3% GL, has also been investigated and appears to produce the most promising results when used long term. DGL also promotes differentiation of undifferentiated cells to mucous cells and stimulates mucus production and secretion. In an uncontrolled trial of 32 patients with chronic duodenal ulcer, 3800 mg/day of DGL (in five divided doses) produced signs of healing in all cases and total restoration of mucosa in a majority of subjects. Although treatment continued for 24 weeks, considerable improvement was seen in 56% of patients by week 12 and in 78% by week 16. A shorter 4-week trial of 96 patients with gastric ulcer failed to produce the same positive results. DGL plus antacid (Caved-S; 2 tablets chewed three times daily between meals) was as effective as cimetidine (200 mg three times daily plus 400 mg at night) after 6 weeks, according to one randomised single-blind trial of 100 volunteers with Read more […]

Licorice: Other Actions

SEX HORMONES Testosterone Whether licorice consumption affects testosterone levels is still unknown, as conflicting results have been obtained from clinical studies. Armanini et al have conducted a series of trials investigating the effects of licorice on testosterone levels in males with mixed results. One study showed that licorice (7 g/day equivalent to 0.5 g GA) was able to reversibly reduce testosterone levels within 7 days, by inhibiting 17,20-lyase (involved in the conversion of 17-hydroxyprogesterone to androstenedione) and 17-beta-hydroxysteroid dehydrogenase (involved in the conversion of androstenedione to testosterone). Another study twice attempted to replicate these results, but was unable to detect an effect on testosterone levels in either study; the authors suggest that inappropriate use of statistical tests in the first study may explain the varying results. More clinically promising are the results from a small trial of nine healthy women (22-26 years) in the luteal phase of their menstrual cycle. The women received 3.5 g licorice (containing 7.6% w/w of GL) daily for two cycles. Total serum testosterone decreased from 27.8 (±8.2) to 19.0 (±9.4) ng/dL in the first month and to 17(±6.4) Read more […]