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 […]

Licorice: Main Actions

MINERALOCORTICOID EFFECT The glycyrrhetinic acid (GA) constituent in licorice (and its metabolite 3-monoglucuronyl-glycyrrhetinic acid) inhibits the enzyme 11HSD, which catalyses the conversion of cortisol into its inactive metabolite, cortisone. This results in delayed excretion and prolonged activity of cortisol. Additionally, glycyrrhizin (GL) and GA bind to mineralocorticoid and glucocorticoid receptors and may displace cortisol from its carrier molecule, transcortin. Pseudohyperaldosteronism As cortisol levels rise, they stimulate mineralocorticoid receptors in the distal renal tubule. This creates pseudohyperaldosteronism, which has the same clinical features as primary aldosteronism, including sodium retention, fluid retention and oedema, hypertension, hypokalaemia and metabolic alkalosis. A case report suggests that the symptoms occur despite low plasma levels of aldosterone. Decreased plasma renin activity and increased cortisol levels result in vasoconstriction of vascular smooth muscle, which may further exacerbate the hypertensive effects. This may be of particular significance in patients with prolonged intestinal transit time where GA levels can accumulate. ANTI-INFLAMMATORY The anti-inflammatory Read more […]

Licorice: Background

Common Name Licorice Other Names Alcacuz, Chinese licorice, licorice root, liquorice, sweet root, gan cao, kanzo, radix glycyrrhizae, yashimadhu Botanical Name / Family Glycyrrhiza glabra L. (family Leguminosae) It should be differentiated from: G. uralensis (synonyms: Chinese licorice, gan cao, licorice root, sweet root), G. inflata (synonyms: gan cao, zhigancao), G. pralidiflora, G. glandifera, G. pallida, G. tyica and G. violocea, although some studies do not always clearly state which form is used. Plant Parts Used Root and stolon Historical Note Licorice root has been used in Europe since prehistoric times, and its medicinal use is well documented. References to licorice date backto approximately 2500 BC on Assyrian clay tablets and Egyptian papyri. It has been used as both a food and a medicine since ancient times. The genus name, meaning ‘sweet root’, is attributed to the first century Greek physician Dioscorides. The herb is also popular in traditional Chinese and Ayurvedic medicine. Chemical Components Licorice contains several triterpenoid saponins, the most studied of which is glycyrrhizin (GL, also known as glycyrrhizic acid or glycyrrhizinic acid). Other important constituents include: Read more […]

Passionflower: Practice Points – Patient Counselling. FAQ

• Both human and animal studies confirm passionflower has significant anxiolytic activity. • One randomised study found that it has significantly less negative effects on performance than 30 mg oxazepam, yet is as effective for GAD. • Maximal effects may require several days of regular intake. • It is not known whether physical tolerance develops. • One study has shown it improves psychological symptoms during opiate withdrawal when used together with clonidine. • In practice, it is often prescribed with other herbs for stronger anxiolytic effect. Answers to Patients’ Frequently Asked Questions What will this herb do for me? Passionflower has an anxiolytic effect that can relieve restlessness and nervous tension. In higher doses, it is used for insomnia. When will it start to work? When being used for anxiety, it may take 3-4 weeks before significant effects are seen. Are there any safety issues? Overall, passionflower does not appear to impair job performance. However, it may theoretically interact with other sedative medicines when used in high doses. Other interactions are theoretically possible, so use should be monitored by a healthcare professional. Read more […]

Passionflower: Adverse Reactions. Pregnancy Use.

Significant Interactions Controlled studies are not available; therefore, interactions are based on evidence of pharmacological activity and are theoretical. BENZODIAZEPINES Additive effects are theoretically possible at high doses. Use with caution and monitor drug dosage — possible beneficial interaction under medical supervision. BARBITURATES Additive CNS sedation is theoretically possible. Use with caution and monitor drug dosage — possible beneficial interaction under medical supervision. ANTICOAGULANTS Increased risk of bleeding is theoretically possible owing to the coumarin content of the herb — observe patients taking this combination. Adverse Reactions Drowsiness is theoretically possible with excessive doses. One human study found that Passiflora extract has a significantly lower incidence of impairment of job performance compared with oxazepam. One case reports a 34-year-old woman who developed severe nausea, vomiting, drowsiness and episodes of non-sustained ventricular tachycardia following administration of passionflower at therapeutic doses. Pregnancy Use Passionflower has demonstrated the ability to increase uterine contractions in an isolated rat uterus model when compared to control Read more […]

Passionflower: Clinical Use. Dosage

ANXIETY AND NERVOUS RESTLESSNESS Passiflora extract is a popular herb for nervousness and is most often prescribed in combination with other herbs such as valerian. A 2001 double-blind, randomised controlled study involving 36 outpatients diagnosed with GAD found that Passiflora extract was as effective as oxazepam 30 mg/day over a 4-week period and better tolerated. Commission E approved for this indication. INSOMNIA Currently, in vivo evidence supports the sedative activity of Passiflora when used in high doses; however, controlled studies are not available to confirm the clinical efficacy. Passionflower: Other Uses TRADITIONAL USES Traditionally, passionflower has been used to treat neuralgia, generalised seizures, hysteria and insomnia. It has also been used to treat diarrhea, dysentery and dysmenorrhoea by acting on the nervous system. APHRODISIAC Recent tests in mice have identified significant aphrodisiac properties associated with high doses of Passiflora extract. A benzoflavone moiety may be chiefly responsible, as tests with this isolated compound were found to increase libido and fertility of males rats after 30 days’ treatment. ANTITUSSIVE AND ANTIASTHMATIC ACTIVITY Passiflora incarnata was Read more […]