Does Cymbalta cause prolonged QT interval? (+7 tips)

In this article, we will discuss whether Cymbalta causes prolonged QT interval. We will share the factors that can contribute to prolonged QT interval while using Cymbalta. Moreover, this article will also mention the safest antidepressants for cardiovascular patients.

Does Cymbalta cause prolonged QT interval?

Yes, Cymbalta can cause prolonged QT interval. However, it is not a common side effect of Cymbalta. The risk of QT interval prolongation associated with Cymbalta is generally higher at higher doses of the medication. 

The QT interval is the measure of the heart’s electrical cycle. Prolongation of the QT interval can potentially lead to a serious, life-threatening heart rhythm disorder known as Torsade de Pointes.

Cymbalta is an antidepressant classified as a serotonin-norepinephrine reuptake inhibitor (SNRI). SNRIs administered at higher doses can exert a more pronounced noradrenergic effect, potentially leading to elevated heart rate and blood pressure.

Cymbalta increases the levels of serotonin and norepinephrine in the brain. These neurotransmitters play a role in the cardiovascular system and can influence the QT interval. They can interact with ion channels in the heart, affecting the electrical conduction system.(1)

However, the specific interactions with ion channels that may contribute to QT interval prolongation are not fully elucidated.

It’s important to note that the risk of Cymbalta affecting heart rhythm is generally considered to be low. However, individuals taking Cymbalta, especially at higher doses, must be closely monitored for QT interval prolongation.  

What does the research suggest?

Studies on QT interval prolongation associated with Cymbalta specifically have shown mixed results. Some studies found no significant QT prolongation, while others reported small but statistically significant increases.

Several large-scale studies have found no significant association between Cymbalta use and QT prolongation. However, studies suggest that higher doses of Cymbalta appear to be linked with a greater risk of prolonged QT interval. (2)

One case report describes two heart failure patients taking Cymbalta 20mg. The two patients developed tachycardia, heart palpitations and chest pain two months after starting Cymbalta. (3)

In addition, approximately 1.6% of 17,386 Cymbalta users experienced cardiovascular events. (4)

Patients with pre-existing cardiovascular conditions should undergo careful monitoring while taking Cymbalta, given the potential cardiovascular risks associated with the medication.


What factors contribute to prolonged QT interval while using Cymbalta?

Several factors can contribute to the prolonged QT interval associated with Cymbalta. Although the risk of QT interval prolongation is considered to be low, this risk is increased by some factors, including (5):

  • Dosage: The incidence of prolonged QT interval is dose-dependent. Higher doses of Cymbalta are more likely to cause QT interval prolongation.


  • Individual sensitivity: Some individuals are genetically more susceptible to QT interval prolongation, regardless of medication use. 


  • Use of concurrent medications: Certain medications, such as other antidepressants, antipsychotics and antibiotics, can interact with Cymbalta and increase the risk of QT interval prolongation.


  • Medical history: Individuals with a history of heart rhythm disorders, congenital long QT syndrome, diabetes mellitus, elevated serum cholesterol levels, and hyperthyroidism are at higher risk of experiencing changes in heart rhythm while using Cymbalta. 


  • Age and gender: Elderly females are more likely to experience QT interval prolongation and other cardiovascular events. 


  • Alcohol consumption: Alcohol can interact with Cymbalta and increase the risk of QT interval prolongation.


  • Electrolyte imbalance: Low levels of potassium, magnesium and calcium can significantly lead to changes in the heart rhythm.


  • Hepatic or renal impairment: These conditions can affect how Cymbalta is metabolized and eliminated from the body, potentially increasing the side effects of the medication.


What to do if Cymbalta causes prolonged QT interval?

If you experience a prolonged QT interval or have concerns about the potential impact of Cymbalta on your heart. It’s crucial to take the following steps:

  • Contact your healthcare provider: Report your symptoms or concerns to your healthcare provider for appropriate management of your condition. Do not stop taking Cymbalta or adjust your dosage without consulting your healthcare provider.


  • Seek medical evaluation: Your healthcare provider will likely conduct a thorough medical evaluation, which may include an electrocardiogram (ECG) to assess your heart’s electrical activity and determine the suitable interventions.


  • Discontinuation or dose adjustment of Cymbalta: In some cases, healthcare providers may choose to discontinue Cymbalta or adjust the dosage to mitigate the risk of QT interval prolongation.


  • Monitoring: Regular monitoring is essential to track your heart rhythm and QT interval. This can help ensure your cardiovascular health is appropriately managed.


  • Review of medications: Your healthcare provider will likely review all medications you are taking to identify potential interactions that can contribute to prolonged QT interval.


  • Lifestyle consideration: Make healthy choices such as regular exercise, a balanced diet and stress management to protect your heart.


What are the safest antidepressants for cardiovascular patients?

Some antidepressants are considered safer for individuals with cardiovascular conditions. However, individual responses to antidepressants vary widely and their safety for individuals with cardiovascular conditions depends on various factors.

Interestingly, selective serotonin reuptake inhibitors (SSRIs) have been proposed to possess beneficial effects on the cardiovascular system through complex pathways. SSRIs are often considered among the safer options for cardiovascular patients. (1) Examples of SSRIs include:

  • Sertraline (Zoloft): It is considered the first-line choice for cardiovascular patients due to its minimal effects on heart rate and blood pressure.


  • Citalopram (Celexa): It’s generally safe for most patients, but higher doses may require monitoring.


  • Escitalopram (Lexapro): It has a similar safety profile to citalopram.


  • Fluoxetine (Prozac): It may have a slight increase in heart rate, but generally considered safe for most patients.


We can conclude that Cymbalta can cause prolonged QT interval. Although it is generally considered to be safe, close monitoring is required, especially when given at higher doses. I recommend you talk to your doctor about your symptoms or concerns regarding prolonged QT interval. Always follow your healthcare provider’s recommendations and attend regular check-ups to monitor your health while on antidepressant therapy.


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Aronow WS, Shamliyan TA. Effects of antidepressants on QT interval in people with mental disorders. Arch Med Sci. 2020 May 29;16(4):727-741.


Zhang L, Chappell J, Gonzales CR, Small D, Knadler MP, Callaghan JT, Francis JL, Desaiah D, Leibowitz M, Ereshefsky L, Hoelscher D, Leese PT, Derby M. QT effects of duloxetine at supratherapeutic doses: a placebo and positive controlled study. J Cardiovasc Pharmacol. 2007 Mar;49(3):146-53.,QT%20corrected%20by%20any%20method.


Stevens DL. Duloxetine-Associated Tachycardia. Annals of Pharmacotherapy. 2008;42(10):1511-1513.


Xue F, Strombom I, Turnbull B, Zhu S, Seeger J. Treatment with duloxetine in adults and the incidence of cardiovascular events. J Clin Psychopharmacol. 2012 Feb;32(1):23-30.


van Noord C, Eijgelsheim M, Stricker BH. Drug- and non-drug-associated QT interval prolongation. Br J Clin Pharmacol. 2010 Jul;70(1):16-23.,slow%20heart%20rate%20and%20electrolyte

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