Licorice is a sweet, flavorful herb that has been used in foods and medicines for thousands of years. Some candies are flavored with licorice, and medicine made from licorice root has been used for a variety of health conditions, such as heartburn, peptic ulcers and sore throat. Licorice interacts with numerous prescription medications, however. Also, people with certain health conditions should not take licorice. Talk to your doctor before using licorice, especially if you take any prescription medications.
Licorice and Hypertension Medications
Licorice should not be used with medications for the management of hypertension, including angiotensin converting enzyme, or ACE, inhibitors and diuretics. These medications include the prescription drugs captopril, enalapril, losartan, chlorothiazide, chlorthalidone and many others. Licorice may interfere with the effectiveness of these medicines or worsen side effects. According to National Institutes of Health online medical encyclopedia Medline Plus, licorice can increase blood pressure, which means it may decrease the effectiveness of medications used to treat high blood pressure, or hypertension. Licorice can also lower blood levels of the essential electrolyte mineral potassium. Diuretics, commonly prescribed for hypertension, also lower potassium, so taking licorice and diuretics may result in dangerously low potassium levels.
Licorice and Estrogens
Licorice also may also interact with prescription medications containing the female hormone estrogen. Licorice may produce estrogenic or anti-estrogenic effects, which means it may raise or lower the level of estrogen in the body, interfering with the effects of medications that provide estrogen, such as hormone therapy pills. Examples of estrogenic drugs that may interact with licorice include conjugated equine estrogens, ethinyl estradiol, estradiol and many oral contraceptives. Additionally, according to the University of Maryland Medical Center, there have been reports of women who took licorice while on oral contraceptives who developed low potassium levels and high blood pressure.
Other Medications that Interact with Licorice
Licorice may cause dangerous interactions with numerous other medications. According to Medline Plus, licorice may increase the breakdown and decrease the effectiveness of warfarin, a drug used to prevent blood clotting. Because of its potassium-lowering effects, licorice interacts with many medications that lower potassium, which, in addition to diuretics, also include digoxin, ethacrynic acid, furosemide, laxatives and corticosteroid medications such as hydrocortisone and prednisone. Taking licorice with medicines that are broken down by the liver, such as celecoxib, lovastatin and ibuprofen, may increase or decrease the effects of these medications. In addition, licorice may interact with MAO inhibitors and medications for diabetes.
Other Considerations
According to the UMMC, people with the following health conditions should not take licorice: heart failure, heart disease, fluid retention, hypertension, diabetes, kidney disease and diabetes. Licorice supplements include teas, tablets and liquid extracts made from licorice root. Some licorice contains an ingredient called glycyrrhizin, which is associated with serious side effects, including heart irregularities and numbness in the arms and legs. Supplements made with deglycyrrhizinated licorice, or DGL, are not associated with these same side effects. Some foods and candies contain licorice, although many "black licorice" products are flavored with anise oil and do not contain any licorice. Candies made with real licorice will usually include "licorice extract" or "licorice root extract" in their list of ingredients.
