How does excess licorice consumption cause hypertension and hypokalemia?

The active ingredient of licorice, glycyrrhizic acid or glycyrrhizin, is first converted to glycyrrhetinic acid (GRA) in the bowel which is then absorbed. Once in the circulation, GRA inhibits activation of 11 β-hydroxysteroid dehydrogenase 2 (11 β-HSD2), an enzyme in renal tissue that converts active cortisol to inactive cortisone. Without the full action of this enzyme, proper sodium and potassium homeostasis would be difficult because cortisol is just as effective in stimulating mineralocorticoid receptors as aldosterone but with 100-1000 times higher concentration than that of aldosterone! 1-3

Other ways that GRA may cause hypertension and hypokalemia include inhibition of 5 β-reductase in the liver, an enzyme that metabolizes aldosterone and direct stimulation of mineralocorticoid receptors, though overall these mechanisms may not be as important as the effect of GRA on cortisol metabolism in renal tissue.1,2

Besides causing fluid retention, licorice ingestion has also been found to increase systemic vascular resistance possibly by increasing vascular tone and remodeling of the vascular wall, potentiating the vasoconstrictor actions of angiotensin II and catecholamines in smooth muscle, and suppressing vasodilatory systems, including endothelial nitric oxide synthase and prostacyclin synthesis.

It’s no wonder that the FDA issued a statement in 2017: “If you’re 40 or older, eating 2 ounces of black licorice a day for a day for at least two weeks could land you in the hospital with an irregular heart rhythm or arrhythmia.” 5

Bonus Pearl: Did you know that as early as 1951, extract of licorice was reported for treatment of Addison’s disease, a combination of licorice and soy sauce has been reported to be “life-saving” in a patient with Addison’s disease (2007), and GRA food supplementation may lower serum potassium in chronic hemodialysis patients (2009)? 6,7



  1. Sontia B, Mooney J, Gaudet L, et al. Pseudohyperaldosteronism, liquorice and hypertension. J Clin Hypertens (Greenwich) 2008; 10:153-57.
  2. Omar HR, Komarova I, El-Ghonemi M, et al. Licorice abuse: time to send a warning message. The Adv Endocrinol Metab 2012;3:125-138.
  3. Penninkilampi R, Eslick EM, Eslick GD. The association between consistent licorice ingestion, hypertension and hypokalaemia: as systematic review and meta-analysis. Journal of Human Hypertension 2017;31:699-707.
  4. Black licorice: trik or treat? 277152.htm
  5. Hautaniemi EJ, Tahvanainen AM, Koskela JK, et al. Voluntary liquorice ingestion increases blood pressure via increased volume load, elevated peripheral arterial resistance, and decreased aortic compliance. Sci Rep 2017;7:10947.
  6. Groen J, Pelser H, Willebrands AF, et al. Extract of licorice for the treatment of Addison’s disease. N Engl J Med 1951;244:471-75.
  7. Cooper H, Bhattacharya B, Verma V, et al. Liquorice and soy sauce, a life-saving concoction in a patient with Addison’s disease. Ann Clin Biochem 2007;44:397-99.
  8. Farese S, Kruse Anja, Pasch A, et al. Glycyrrhetinic acid food supplementation lowers serum potassium concentration in chronic hemodialysis patients. Kidney International 2009;76:877-84.
How does excess licorice consumption cause hypertension and hypokalemia?

My patient with chronic pain complains of difficulty sleeping. Would improving her sleep hygiene impact her pain medication requirement?

Most likely!

We should routinely assess for poor sleep as a potential impediment to adequate pain control in our patients. Substantial research supports a bidirectional relationship between pain and sleep.  That is, not only can pain disrupt sleep but sleep quality can also adversely affect pain.1   In fact, even a short-term disturbance in a stable sleep pattern may lower the pain threshold 2 and the ability to tolerate previously controlled pain.3

These observations are thought to result from activated stress responses from poor sleep hygiene which in turn produce cellular oxidative stress and inflammation of tissues and the nervous system. 4 This process can result in a vicious cycle between increasing pain and persistent insomnia.4,5  Breaking this cycle can reduce pain and improve function, among other desired outcomes.

Ongoing insomnia may also be a sign of a variety of other conditions that should be treated, such as mood disorder and sleep apnea. For example, besides standard non-pharmaceutical measures to improve sleep hygiene, continuous positive air pressure (CPAP) can reduce pain and opioid use in the setting of sleep apnea .2,6

Remember also that controlling pain with opioids in hopes of improving sleep may be counterproductive as opioids can contribute to sleep apnea.7,8  Melatonin may be a better sleep aid in this setting. 9


  1. Wei Y, Blanken TF, Van Someren EJW. Insomnia really hurts: effect of a bad night’s sleep on pain increases with insomnia severity. Front Psychiatry 2018;9:377. doi: 10.3389/fpsyt.2018.00377.
  2. Charokopos A, Card ME, Gunderson C, Steffens C, Bastian LA. The association of obstructive sleep apnea and pain outcomes in adults: a systematic review. Pain Med 2018;19(suppl_1):S69-S75. doi: 10.1093/pm/pny140.
  3. Sivertsen B, Lallukka T, Petrie KJ, et al. Sleep and pain sensitivity in adults. Pain. 2015;156:1433-9.
  4. Iacovides S, George K, Kamerman P, Baker FC. Sleep fragmentation hypersensitizes healthy young women to deep and superficial experimental pain. J Pain. 2017;18:844-854. doi:
  5. Edwards RR, Almeida DM, Klick B, Haythornthwaite JA, Smith MT. Duration of sleep contributes to next-day pain report in the general population. Pain. 2008;137:202-7. doi: 10.1016/j.pain.2008.01.025.
  6. Edwards RR, Almeida DM, Klick B, Haythornthwaite JA, Smith MT. Duration of sleep contributes to next-day pain report in the general population. Pain. 2008 Jul;137(1):202-7. doi: 10.1016/j.pain.2008.01.025.
  7. Marshansky S, Mayer P, Rizzo D, Baltzan M, Denis R, Lavigne GJ. Sleep, chronic pain, and opioid risk for apnea. Prog Neuropsychopharmacol Biol Psychiatry 2018 20;87:234-244.
  8. Jungquist CR, Flannery M, Perlis ML, Grace JT. Relationship of chronic pain and opioid use with respiratory disturbance during sleep. Pain Manag Nurs 2012;13:70-9. doi: 10.1016/j.pmn.2010.04.003.
  9. Landis CA. Is melatonin the next “new” therapy to improve sleep and reduce pain? Sleep 2014; 37: 1405–1406.

Contributed by Paul Arnstein, PhD, RN, FAAN, Mass General Hospital, Boston, MA.

My patient with chronic pain complains of difficulty sleeping. Would improving her sleep hygiene impact her pain medication requirement?