Cymbalta (duloxetine) is an antidepressant drug manufactured by Eli Lilly and Company prescribed to treat a variety of conditions in addition to depression — including anxiety, fibromyalgia, and chronic muscle and bone pain.

While the drug has been popular, with almost $24 billion in total sales, patients who stop taking Cymbalta may face an increased risk of severe withdrawal side effects known as Cymbalta Discontinuation Syndrome.

A study published by the Journal of Affective Disorders linked serious withdrawal side effects to the abrupt discontinuation of Cymbalta in almost half of patients taking the drug.

Although the warning label states that symptoms of withdrawal “occurred at a rate greater than or equal to 1%,” recent studies have determined them to be much more frequent and severe. In six double-blind trials of Cymbalta funded and conducted by Eli Lilly, about 44 percent of patients reported withdrawal symptoms, 50.6 percent of which were considered “moderate” while 9.6 percent were classified as “severe.”

Another much larger open-label trial (where test subjects knew they were taking Cymbalta) determined that approximately 51 percent of patients suffered Cymbalta withdrawal symptoms (46.3 percent moderate, 17.2 percent severe).

Nowhere on the Cymbalta warning label does it state that such a large percentage of patients (up to 51 percent) will experience withdrawal, or that the majority of those symptoms will be moderate to severe. Cymbalta withdrawal side effects can last for days or weeks and may even contribute to dependence among patients who want to stop taking the drug.

Patients who discontinue use of antidepressant drugs often experience some degree of withdrawal side effects. However, the side effects from Cymbalta can be so severe that doctors have assigned them a diagnosis of their own – Cymbalta Discontinuation Syndrome.

This condition’s symptoms include:

• Blackouts – periods of lost time, in which there are no memories of what has happened.
• “Brain zaps” – a sensation, often triggered by movement, of an electrical storm in your brain. Highly disturbing, and very common.
• Dizziness/vertigo – sometimes so severe patients are bedridden.
• Emotional instability – unexplained crying or anger.
• Suicidal ideations – the impulse to kill oneself.
• Insomnia
• Vomiting/diarrhea

According to an FDA Warning, Cymbalta Discontinuation Syndrome can cause “injury, distress and life management impacts” when a patient quits taking the drug. These Cymbalta withdrawal symptoms may be so severe that patients have to keep taking Cymbalta simply to lessen the effects of the withdrawal, causing a person to become dependent on the drug.

The duration of Cymbalta withdrawal varies from patient to patient, but can last for three months or more. Symptoms may appear after Cymbalta is discontinued or the dosage is lowered.

The Cymbalta prescribing information states: “A gradual reduction in the dose rather than abrupt cessation is recommended whenever possible.” However, gradually stepping down the dosage of Cymbalta is extremely limited because the drug is only available in 20 mg, 30 mg and 60 mg capsules that cannot be divided or cut in half.