Cymbalta (duloxetine) is commonly used to treat depression and generalized anxiety. The drug belongs to a class of antidepressant medicines known as serotonin and norepinephrine reuptake inhibitors (SNRIs). In some cases Cymbalta may be prescribed to treat pain due to diabetic neuropathy and fibromyalgia.

History of Cymbalta

In August 2004, the U.S. Food and Drug Administration (FDA) approved duloxetine for the treatment of depression under the brand name Cymbalta. Shortly afterward, Cymbalta became the first and only officially indicated drug in the United States for the management of pain from diabetic peripheral neuropathy. In February 2007, Cymbalta got approval from the FDA for the treatment of generalized anxiety.

How Does Cymbalta Work?

Cymbalta inhibits the reuptake of serotonin and norepinephrine in the central nervous system. It also increases dopamine by acting on dopamine reuptake pumps, thus increasing the diffusion of dopamine in the brain. It also decreases pro-inflammatory cytokines and increases the anti-inflammatory ones, which assist in relieving depression symptoms. The pain-relieving properties of this drug are thought to be due to the blocking of sodium channels.

Dosage FAQs

  • What are the normal dosages for this medication?
    • Major depression: A normal dose of this drug for patients over 18 is 60 mg once daily.
    • Generalized anxiety: In adults over 18 years of age, an initial dose of 30 mg daily is administered, which can be increased to 60 mg; the maximum dose should not exceed 120 mg.
    • Diabetic neuropathy: The dose for diabetic neuropathy is 60 mg once daily but should not exceed 120 mg daily. Cymbalta should be discontinued of there is no response and the treatment should be reviewed every three months.
       
  • How does my body process this drug?
    Cymbalta is absorbed in the gastrointestinal tract and has a moderate bioavailability (about 50%). The onset of action is after about 2 hours and it reaches a maximum plasma concentration after about 6 hours. This medication is metabolized in the liver. If taken with food, this drug may not reach peak concentration for about 10 hours. It has a half-life of 12 hours after which it is excreted in the urine (70%) and feces (30%).
     

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    Is it safe to use this drug if I am pregnant or become pregnant during treatment?
    Cymbalta should be used with great caution during pregnancy and should be only used if the potential benefits outweigh the risk. This question should be carefully considered by you and your doctor before reaching a decision.
  • What are some ways to get the most out of my treatment with this drug?
    Cymbalta is prescribed for several mental health conditions that are often effectively treated with psychotherapy. If you are prescribed this drug for depression or anxiety, consider finding a qualified therapist or counselor to help with your mental health treatment. While psychotropic medication can be great for dulling or relieving debilitating symptoms, it cannot teach a person positive coping methods, self-care strategies, or help someone understand what they are experiencing better. Connecting with a therapist and building a good therapeutic relationship may help improve a person’s quality of life and result in a better mental health outcome than treatment with medication alone.

Possible Side Effects

The most frequent adverse effects of this medication include, but are not limited to the following:

  • Changes in libido
  • Altered appetite
  • Nausea, vomiting, and diarrhea
  • Sleeplessness
  • Drowsiness
  • Dry mouth
  • Fatigue
  • Increased sweating

The patient should stop taking the drug if they experience seizures, painful skin rashes, symptoms of allergic reaction, difficulty breathing, and symptoms of serotonin syndrome that include experiencing confusion, restlessness, sweating, shivering, shaking, hallucinations, rapid heartbeat, and sudden muscle jerking.

Drug Interactions

This medication carries with it several important drug interactions of which to be aware. If you are prescribed this medication, please consult your doctor and/or pharmacist on the following drug interactions:

Precautions

While taking this drug, you should be aware of the following important warnings:

  • Bleeding: It is possible for this drug to increase risks of excessive bleeding, especially if you take medications such as aspirin, ibuprofen, ketoprofen, or warfarin.
  • Blood pressure and heart rate: Cymbalta may cause an increase in blood pressure and/or rapid heart rate. If you have been diagnosed with high blood pressure or other types of heart disease, caution is recommended. Inform your doctor of your entire heart health history before taking this drug.
  • Bone fractures: This drug may increase the risk of a bone fracture, especially for elderly people.
  • Diabetes: This medication may cause drowsiness for people with diabetes and may decrease the control of blood sugar.
  • Kidney impairment: Kidney impairment may cause an accumulation of this drug and its metabolites in your system.
  • Liver impairment: Cymbalta is metabolized in the liver, so liver impairment may increase the incidence of side effects.
  • Suicidal behavior and thoughts: This drug may increase suicidal ideation and behavior. Inform your doctor of any severe changes in mood or development of suicidal thoughts.

How to Safely Withdraw

Quitting this drug abruptly can result in severe withdrawal symptoms. In fact, in light of much anecdotal evidence, the FDA has labeled severe withdrawal from this drug Cymbalta Discontinuation Syndrome. Stopping this medication without a safe plan between you and your physician may cause these side effects:

  • Dizziness
  • Abnormal, sometimes frightening dreams
  • Difficulty falling or staying asleep
  • Numbness or tingling sensations in body extremities
  • Increased irritability
  • Anxiety
  • Nausea, vomiting, or diarrhea
  • Flu-like symptoms including sweating and muscle and joint pain

The dose should be tapered down gradually to minimize the effects of withdrawal.

References:

  1. Alessandro, S. and Kato, M. (2008). The serotonin transporter gene and effectiveness of SSRIs. Expert Review of Neurotherapeutics, 8(1), 111.
  2. Bab, I. and Yirmiya, R. (2010). Depression, selective serotonin reuptake inhibitors, and osteoporosis. Current Osteoporosis Reports, 8, 185.
  3. Barrera, A.Z., Torres, L.D., and Munoz, R.F. (2007). Prevention of depression: The state of the science at the beginning of the 21st century. International Review of Psychiatry, 19(6), 655.
  4. Bellingham, G.A. and Peng, P.W. (2010). Duloxetine: A review of its pharmacology and use in chronic pain management. Regional Anesthesia Pain Medication, 35, 294.

Page content reviewed by James Pendleton, ND.