Is Irenka (Duloxetine) equivalent to Cymbalta (Duloxetine)?

From the FDA Drug Label

1. Indications and Usage Duloxetine delayed

-release capsules are indicated for the treatment of: Major depressive disorder in adults Generalized anxiety disorder in adults and pediatric patients 7 years of age and older Diabetic peripheral neuropathic pain in adults Fibromyalgia in adults Chronic musculoskeletal pain in adults Additional pediatric use information is approved for Eli Lilly and Company, Inc.’s CYMBALTA (duloxetine) delayed-release capsules. However, due to Eli Lilly and Company Inc.’s marketing exclusivity rights, this drug product is not labeled with that pediatric information. The drug Irenka is not mentioned in the label, but duloxetine is, which is also known as Cymbalta (by Eli Lilly and Company, Inc.).

• Duloxetine and Cymbalta are the same medication, duloxetine.
• The label for duloxetine does mention Cymbalta, indicating they are the same. 1

From the Research

Switching from Irenka to Cymbalta is not a medication change, but rather a switch between brand names of the same medication, duloxetine, and can be done at the same dosage level under medical supervision. Irenka and Cymbalta both contain duloxetine as their active ingredient, so the transition should be straightforward with no taper needed [ 2 ]. You can typically switch at the same dosage level (for example, 30mg of Irenka to 30mg of Cymbalta). Since these are the same medication with potentially different inactive ingredients, most patients experience no difference in effectiveness. However, some patients might notice subtle differences due to the formulation of inactive ingredients. If you experience any new side effects after switching, contact your healthcare provider.

Key Considerations

• Always take duloxetine with food to reduce stomach irritation, and never abruptly stop taking either medication as this can cause discontinuation symptoms [ 3 ].
• Insurance coverage often drives these brand switches, as formularies may prefer one brand over another.
• Duloxetine has been shown to be effective in the treatment of major depressive disorder, with significant improvements in core emotional symptoms and painful physical symptoms associated with depression [ 4 ].
• The medication is generally well tolerated, although it may be appropriate to avoid initiating treatment with the 60 mg/day dosage due to a higher discontinuation rate due to adverse events in some studies [ 4 ].

Potential Side Effects

• Nausea is a common side effect of duloxetine, and has been cited as the primary reason for discontinuation of the medication in trials [ 3 ].
• Increases in blood pressure have been mild, but caution should be used in patients with hypertension [ 3 ].
• Patients with a creatinine clearance of <30 mL/min and patients with hepatic impairment should avoid duloxetine [ 3 ].

Switching Strategy

• Switching antidepressants is an appropriate strategy to use if there is a minimal response to an initial antidepressant [ 2 ].
• Broadly, switching within class after non-response is recommended for mild-moderate depression and out-of-class for patients with a more severe depression or melancholia [ 2 ].