Taking Prozac (Fluoxetine) With Licorice

There is no interaction but both increase the risk of arrhythmia.

Taking Prozac (Fluoxetine) With Licorice
Sep 01, 2018

Kim asked

How does licorice interact with fluoxetine?

At a glance

  • Prozac and black licorice are both associated with cardiac arrhythmias, although this is rare. 
  • You should speak with your doctor before consuming black licorice if you take any drug associated with cardiac abnormalities.
  • DGL (deglycyrrhizinated licorice) may be a safer alternative if you are looking to supplement with a black licorice product.



There are no known interactions between Prozac (fluoxetine) and licorice or licorice root extracts. However, rarely, both have been associated with QT prolongation and various cardiac arrhythmias.

Therefore, caution is recommended when considering combining fluoxetine with licorice in individuals with cardiac disease or other conditions that may increase the risk of QT prolongation/arrhythmias.

Below, I discuss additional information regarding Prozac (fluoxetine) and licorice.

What Is Prozac?

Prozac (fluoxetine) is a selective serotonin reuptake inhibitor (SSRI), indicated to treat depression and anxiety disorders.

SSRI medications like Prozac have a complex mechanism of action but overall, work by increasing the amount of the neurotransmitter serotonin and altering serotonin receptors in the brain.

In general, Prozac needs to be dosed consistently for 4-6 weeks for the effects of the medication to be realized. While effective, Prozac is associated with a variety of potential side effects, including:

  • Weight fluctuations (gain and loss)
  • Headache
  • Nausea
  • Vomiting
  • Dizziness
  • QT prolongation
  • Sexual dysfunction

Prozac is dosed once daily and can be taken with or without food.

Black Licorice Info

Licorice is an herb native to the Mediterranean and the Middle East but is cultivated around the world. One of the primary active constituents of licorice is glycyrrhizic acid.

Glycyrrhizic acid has a variety of effects on the body but has been reported to cause electrolyte imbalances and increase the risk of cardiac arrhythmias. The negative effects have been extensively reported by the FDA and news outlets.

Per the FDA:

  • No matter what your age, don’t eat large amounts of black licorice at one time.
  • If you have been eating a lot of black licorice and have an irregular heart rhythm or muscle weakness, stop eating it immediately and contact your healthcare provider.
  • Black licorice can interact with some medications, herbs and dietary supplements. Consult a health care professional if you have questions about possible interactions with a drug or supplement you take.

It is important to note that many licorice supplements are processed to remove glycyrrhizic acid and are named DGL (deglycyrrhizinated licorice). DGL supplements are not thought to carry the risk that glycyrrhizic acid-containing licorice does.

Final Words

There are no known interactions between Prozac (fluoxetine) and licorice. However, due to the fact that both can increase the risk of cardiac arrhythmias in susceptible individuals, combining Prozac and licorice should only be done under your doctor's recommendation/supervision.

  1. Constituent properties of licorices derived from Glycyrrhiza uralensis, G. glabra, or G. inflata identified by genetic information. PubMed
  2. Black Licorice: Trick or Treat? FDA
  3. Health risks of black licorice candy. Consumer Reports
  4. An unusual cause of hypokalemic paralysis: chronic licorice ingestion. PubMed
  5. Prozac Prescribing Information. Lilly
  6. Glycyrrhizic acid in liquorice--evaluation of health hazard. PubMed
  7. Licorice-induced hypermineralocorticoidism. PubMed
  8. Drug-Induced Prolongation of the QT Interval. New England Journal of Medicine

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