The licorice plant (Glycyrrhiza glabra) root extract contains glycyrrhizin, a compound with significant biological activity that can interact with various medications. Glycyrrhizin functions similarly to the hormone aldosterone, promoting the body's retention of sodium and water while increasing potassium excretion. This effect, termed pseudoaldosteronism, underlies many problematic drug interactions with licorice. This guide highlights medications and drug classes where combining with licorice poses notable risks.
Medications with Significant Interaction Risks
Interactions between licorice and certain medications can be serious, potentially reducing drug effectiveness or increasing toxicity.
Cardiac and Blood Pressure Drugs
Licorice can particularly impact medications for heart conditions and high blood pressure. For instance, diuretics, often called 'water pills,' help the body eliminate excess fluid and sodium, which can lead to potassium loss. Since licorice also causes potassium to be excreted, taking them together can result in critically low potassium levels (hypokalemia). Severe hypokalemia may cause muscle weakness, abnormal heart rhythms, and paralysis. This applies to loop diuretics like furosemide, thiazide diuretics such as hydrochlorothiazide, and can even counteract the effects of potassium-sparing diuretics like spironolactone.
Digoxin (Lanoxin), used for heart failure and irregular heartbeats, is also affected. Low potassium levels induced by licorice significantly raise the risk of digoxin toxicity, which can manifest as nausea, vomiting, blurred vision, and life-threatening cardiac arrhythmias.
Furthermore, licorice can be dangerous for people with high blood pressure (hypertension) as it can raise blood pressure by causing the body to hold onto sodium and water. This effect can diminish the impact of antihypertensive medications. Patients using blood pressure drugs should be careful to avoid licorice.
Blood Thinners
Warfarin (Coumadin), a medication to prevent blood clots, can be affected by licorice. Licorice may reduce how well warfarin works, potentially increasing the chance of developing dangerous blood clots. Due to this risk, healthcare providers usually recommend avoiding licorice entirely while on warfarin.
Corticosteroids
Licorice can amplify the effects and side effects of corticosteroids like prednisone and cortisone acetate, potentially increasing the risk of adverse reactions. This can be especially problematic for those with conditions that require precise corticosteroid management.
Additional Potential Interactions
Licorice may also interact with other substances, including estrogen-based medications like birth control due to potential estrogen-like effects. It might also influence liver enzymes responsible for drug metabolism, potentially altering drug levels in the body. There is also some evidence suggesting licorice could reduce the effectiveness of certain chemotherapy drugs such as paclitaxel and cisplatin.
A Comparison of Licorice's Key Drug Interactions
| Medication Class | Interaction Mechanism | Potential Risk |
|---|---|---|
| Diuretics | Increases potassium loss (hypokalemia) and counteracts effects. | Irregular heartbeat, severe potassium deficiency, impaired fluid removal. |
| Digoxin (Lanoxin) | Decreases potassium, increasing digoxin toxicity. | Potentially fatal cardiac arrhythmias, nausea, vomiting, vision issues. |
| Antihypertensives | Raises blood pressure through sodium and water retention. | Reduces effectiveness of blood pressure medication, causing uncontrolled hypertension. |
| Warfarin (Coumadin) | Decreases effectiveness of the anticoagulant. | Increased risk of dangerous blood clots. |
| Corticosteroids | Increases hormone levels and side effects. | Increased adverse reactions from corticosteroids. |
| Spironolactone | Counteracts the therapeutic effect of the diuretic. | Reduced effectiveness of spironolactone for blood pressure or edema. |
