Does Cymbalta raise blood sugar? (3+ factors)

In this article, we will answer the question “Does Cymbalta raise blood sugar?”. We will discuss the research findings, the factors affecting blood sugar while taking Cymbalta and alternatives that can be prescribed to overcome any blood sugar changes.

Does Cymbalta raise blood sugar?

Yes, Cymbalta does tend to slightly increase blood sugar levels in some individuals undergoing treatment. However, the rise in blood sugar may not be evident in everyone as the effects of Cymbalta may vary from person to person.

Cymbalta (also known as Duloxetine) is an antidepressant belonging to the class of serotonin and norepinephrine reuptake inhibitors (SNRIs).  It is approved by the FDA for the treatment of major depressive disorder (MDD), generalised anxiety disorder (GAD), fibromyalgia, diabetic peripheral neuropathic pain (DPNP) and chronic musculoskeletal pain (1).

Small increases in blood glucose and total cholesterol levels have been observed in individuals on Cymbalta.  The FDA has also warned of worsening glycemic and lipid control in patients receiving Cymbalta for DPNP. So the use of Cymbalta for such patients requires extra caution (1).

How does Cymbalta raise blood sugar?

Cymbalta has not been shown to increase blood glucose while used for a short duration. Even when used for a longer duration, only a slight increase is noted.

A proposed mechanism by which Cymbalta can induce such a change is the increase in weight caused by this medication. Weight gain can lead towards obesity and impaired glycemic control.  Other mechanisms by which Cymbalta can affect blood sugar levels are the disruption in the homeostasis of glucose, increased resistance and decreased secretion of insulin from the pancreas (2).

However, much more research is required to assess how Cymbalta can affect glycemic control and cause an increase in blood sugar levels.

What does research suggest?

A few research studies on the impact of Duloxetine on blood glucose have been published. Most of these studies report a slight increase in the blood glucose levels.

A research study assessing the safety and efficacy of Duloxetine in the doses of 40mg and 60 mg for the long-term treatment of diabetic neuropathic pain reported a significant increase in plasma glucose and total cholesterol levels in individuals who received this medication for 52 weeks (3).

Another study evaluating the change in glycemic control in patients using Duloxetine for DPNP reported an increase in fasting blood sugar levels. Mild changes were also seen with some lipid parameters (4).

In a meta-analysis of glycemic control in patients having conditions other than DPNP it was concluded that Duloxetine did not cause significant changes in fasting plasma glucose and HbA1C levels (5).

Another study, examining the effect of Duloxetine on glycemic control also reinforced this claim by stating that Duloxetine was not associated with a rise in blood sugar in individuals taking it for the management of symptoms of DPNP (6).

What factors can affect blood sugar levels while on Cymbalta?

The following factors may contribute to an increase in blood sugar while the individual is also on Cymbalta therapy:


The dose of the medication can affect plasma glucose levels. Increased activity of serotonin and norepinephrine can become a cause for the rise in blood sugar.


Any underlying medical condition like diabetes and pancreatitis can cause an increase in blood sugar levels while the individual is taking Cymbalta.

Physical inactivity

Physical inactivity can increase the insulin resistance of the body. Individuals who have a sedentary lifestyle and are also taking Cymbalta may have increased blood glucose levels.


Obesity or an increase in weight can be a cause of disruption in the glycemic control of individuals. As Cymbalta can also cause an increase in weight, obese individuals may be at a higher risk of hyperglycemia.

Concomitant medications

Using other antidepressants like selective serotonin reuptake inhibitors (SSRIs), tricyclic antidepressants (TCAs) or other medications like corticosteroids can increase blood glucose levels while the patient is taking Cymbalta.

Unhealthy diet

Poor nutrition or an unhealthy diet may cause imbalances in blood glucose levels due to the absence of healthy and nutritious components in the diet.


Cortisol is a hormone released during stress. It also increases blood glucose levels. If an individual is stressed cortisol is released which can then cause increased levels of blood glucose in patients.

What to do if Cymbalta increases your blood sugar?

If Cymbalta is increasing your blood sugar levels, you should consult your healthcare provider and discuss your concerns. If Cymbalta is the cause of increased blood glucose levels then your doctor may gradually taper off your medication and prescribe another drug for your condition.

However, before reducing the dose of Cymbalta your healthcare provider will evaluate your symptoms, and thoroughly assess your condition to determine whether Cymbalta is the actual reason for the increase in your blood sugar levels or if any other underlying condition is the culprit of this effect.

Only after proper evaluation will the dose of Cymbalta be reduced and another antidepressant prescribed. If Cymbalta is not the problem, then the underlying condition will be treated and Cymbalta therapy will be continued.

Keep in mind not to stop your medication or make any changes in your dosage without the advice of your healthcare provider.

What are alternatives to Cymbalta if it raises blood sugar?

Many alternatives can be given to individuals if Cymbalta is causing a rise in blood sugar levels. The efficacy of these alternatives depends on the individual characteristics, the condition being treated and the response of the patient to the medication. Some of these alternatives are as follows:

  • Citalopram
  • Escitalopram
  • Fluoxetine
  • Milnacipran
  • Trazodone

In this article, we answered the question of whether Cymbalta can cause a rise in blood sugar levels. We discussed the mechanisms by which Cymbalta can cause an increase in blood glucose levels and factors which influence blood glucose levels while on Cymbalta. We also discussed what you should do if Cymbalta increases blood sugar levels and alternatives that can be given in this condition.

In my opinion, some individuals may notice an increase in blood sugar levels while on Cymbalta therapy. However, the response of every person differs when taking Cymbalta so not everyone will experience this side effect. But if you do experience a rise in blood sugar levels you should immediately consult your healthcare provider about dose reduction or alternative treatments.

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The Food and Drug Administration (FDA). HIGHLIGHTS OF PRESCRIBING INFORMATION. CYMBALTA® (duloxetine hydrochloride) Delayed released capsules for oral use. Available from: 


Burcu M, Zito JM, Safer DJ, Magder LS, Shaya FT, Rosenthal GL. Association of antidepressant medications with incident type 2 diabetes among Medicaid-insured youths. JAMA pediatrics. 2017 Dec 1;171(12):1200-7.


Yasuda, H., Hotta, N., Kasuga, M., Kashiwagi, A., Kawamori, R., Yamada, T., Baba, Y., Alev, L. and Nakajo, K., 2016. Efficacy and safety of 40 mg or 60 mg duloxetine in Japanese adults with diabetic neuropathic pain: Results from a randomized, 52‐week, open‐label study. Journal of Diabetes Investigation, 7(1), pp.100-108.


Hardy T, Sachson R, Shen S, Armbruster M, Boulton AJ. Does treatment with duloxetine for neuropathic pain impact glycemic control?. Diabetes Care. 2007 Jan 1;30(1):21-6.


Crucitti A, Zhang Q, Nilsson M, Brecht S, Yang CR, Wernicke J. Duloxetine treatment and glycemic controls in patients with diagnoses other than diabetic peripheral neuropathic pain: a meta-analysis. Current medical research and opinion. 2010 Nov 1;26(11):2579-88.


RASKIN J, Wang F, Wernicke JF, Stroud C, Clemens JW. Duloxetine does not affect glycemic control or lipid profiles in patients with diabetic neuropathic pain. Poster APA, Atlanta. 2005.

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