Common Trade Names
Multi-ingredient preparations : Alvita Teas Licorice Root, Alvita Teas Licorice Sticks, Full Potency Licorice Root Vegicaps, Gaia Herbs Licorice Root A/F, Gaia Herbs Licorice Root SFSE, Licorice ATC Concentrate, Licorice and Garlic, Licorice Root Extract, Licorice Root Tea, Natrol Licorice Root Capsules, Natural Arthro- Rx, Nature’s Answer Licorice Root Low Alcohol and Alcohol Free, Nature’s Herbs Licorice Phytosome Capsules, Nature’s Herbs Licorice Power-Certified Potency Capsules, Solaray Licorice Root, Tea with Mint, Tubi’s Organic Licorice Licorice Bars and Chews, Tummy Soother
Capsules: 100 to 520 mg licorice root
Liquid extracts: licorice extract, deglycyrrhizinized licorice extract
Tablets: 7 mg of licorice root and 333 mg of pure concentrated garlic
Also available in candy, chewing gum, herbal teas, throat lozenges, and tobacco products.
Most medicinal products use the roots and dried rhizomes of Glycyrrhiza Zabra, a perennial herb or low-growing shrub. Spanish licorice, the most common variety, is derived from G. glabra var. typica. Licorice plants are native to the Mediterranean but widely cultivated in the United States, Russia, Spain, Turkey, Greece, India, Italy, Iran, and Iraq.
The rhizomes and roots contain 5% to 9% glycyrrhizin (glycyrrhizic acid), a glycoside that is 50 times sweeter than sugar. Hydrolysis of glycyrrhizin yields glycyrrhetic acid, which is not sweet. Other compounds include ammonia, oleane triterpenoids, glucose, mannose, and sucrose. Aqueous extracts of licorice contain 10% to 20% glycyrrhizin.
Glycyrrhizin is hydrolyzed by intestinal flora to the pharmacologically active form, glycyrrhetic acid. The main effect oflicorice is to potentiate, rather than mimic, endogenous steroids .
Studies in animals suggest that glycyrrhizin and glycyrrhetic acid have mild anti-inflammatory effects. Glycyrrhizin may stimulate gastric mucous synthesis through effects on prostaglandins, which may explain its ulcer-healing properties.
Anecdotally, licorice has effective demulcent (soothing) and expectorant properties and mild laxative and antispasmodic effects. A Chinese licorice preparation called Zhigancao has been found to have antiarrhythmic effects, including prolonged PR and QT intervals. Glycyrrhizin may also lower cholesterol and triglyceride levels and exert antianemic, antihepatotoxic, and immunosuppressive effects.
Because of its anecdotal use for gastric irritation, licorice derivatives have been studied for antipeptic action. Licorice was also evaluated as a treatment for Addison’s disease and was found to enhance mineralocorticoid activity but could not mimic it when adrenal activity was absent.
Glycyrrhizic acid has been used as a shampoo to reduce sebum secretion from the scalp and for cold sores, eczema, and mouth ulcers.
In the United States, glycyrrhizin is used mainly as a flavoring and sweetening agent for bitter drugs, and in beverages, candies, chewing gum, tobacco products, and toothpastes. It is also added to some cough and cold preparations for its expectorant and demulcent effects.
For peptic ulcer, 200 to 600 mg P.O. of glycyrrhizin daily for no longer than 6 weeks, according to the German Commission E .
The following tea is believed to provide glycyrrhizin in the middle of this dosage range: 1 tsp (2 to 4 g) of crude licorice to Yo cup (120 ml) of boiling water, simmered for 5 minutes. Cool, strain, and take P.O. t.i.d. after food.
CNS: hypertensive encephalopathy .
CV: heart failure and cardiac arrest (with overdose), ventricular tachycardia .
EENT: transient visual loss and disturbances after ingestion of 1,4 to 2lb oflicorice candy.
Endocrine: growth retardation reduced serum testosterone levels .
GU: renal tubular damage.
Metabolic: hypokalemia pseudoprimary hyperaldosteronism .
Musculoskeletal: muscle weakness (with hypokalemia), myopathies, rhabdomyolysis.
Respiratory: pulmonary edema .
Antihypertensives, diuretics: May increase hypokalemic effects of some diuretics. Avoid administration with licorice.
Corticosteroids (including topicals): May increase effects. Use together cautiously.
Digoxin: May induce hypokalemia; risk of digitalis toxicity. Avoid administration with licorice.
Loratadine, procainamide, quinidine, other drugs that may prolong QT interval: May have additive effects. Use together cautiously.
Spironolactone: May block ulcer-healing and aldosterone-like effects of licorice. Avoid administration with licorice.
Contraindications and precautions
Licorice is contraindicated in patients with arrhythmias; CV, renal, or hepatic disease; or hypertension. Avoid using it in pregnant or breastfeeding patients; effects are unknown. Use cautiously under medical supervision in elderly patients.
Monitor for hypokalemia in the patient receiving diuretics.
A single large dose of licorice is less likely to cause toxicity than prolonged intake of smaller amounts.
Alert Licorice poisoning may be insidious. Monitor for pseudoprimary hyperaldosteronism causing mineralocorticoid-like effects (headache, lethargy, sodium and water retention, hypokalemia, hypertension, and heart failure). Monitor for electrolyte (potassium, calcium, and sodium) imbalances, alkalosis, electrocardiographic abnormalities, and hypertension.
Caution the patient about the dangers of excessive and chronic licorice intake, including fluid retention and electrolyte imbalances.
Inform the patient of potential drug interactions.
Points of Interest
Licorice has been used medicinally since Roman times and is popular in Chinese herbal medicine .
Most “licorice candy” sold in the United States is flavored with anise oil and does not actually contain licorice.
Although licorice derivatives have been studied for use against peptic ulcer disease, such products have not performed better than H 2 antagonists and may be less well tolerated. Glycyrrhetic acid may playa role in increasing the topical action of low-potency steroids while minimizing systemic effects, but this research is still preliminary. Glycyrrhetic acid is the chief cause of licorice-induced pseudohyperaldosteronism syndrome seen with licorice ingestion, because of its inhibitory effect on the enzyme 11 beta-hydroxysteroid dehydrogenase. Surprisingly, licorice in any form, even as candy, should be considered cautiously because chronic ingestion of low doses as well as high doses can be toxic, exemplified by a multitude of serious adverse events documented in the literature.
By: Robert Baird
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