Does duloxetine (Cymbalta) cause cardiac complications or myalgia?

From the Guidelines

Duloxetine (Cymbalta) does not seem to produce clinically important electrocardiographic or blood pressure changes, but it can cause nausea and other side effects, and its efficacy in types of neuropathic pain other than painful diabetic neuropathy is unknown. When considering the use of duloxetine, it is essential to weigh its potential benefits against its potential risks, particularly in patients with pre-existing medical conditions. According to the study published in the Mayo Clinic Proceedings 1, duloxetine has shown consistent efficacy in painful diabetic neuropathy, with effectiveness sustained for 1 year in an open-label trial. However, its efficacy in other types of neuropathic pain is unknown. Some key points to consider when prescribing duloxetine include:

• Duloxetine does not seem to produce clinically important electrocardiographic or blood pressure changes, making it a potentially safer option for patients with cardiac concerns compared to other medications like venlafaxine, which can cause cardiac conduction abnormalities and blood pressure increases 1.
• The most common adverse effect of duloxetine is nausea, which can be reduced by administering 30 mg once daily for 1 week before increasing to 60 mg once daily 1.
• Duloxetine's dosing is simple, with 60 mg once daily appearing to be as effective as 60 mg twice daily 1.
• A recent review concluded that aminotransferase monitoring is unnecessary for patients taking duloxetine 1. In terms of myalgia, while the study does not specifically address muscle pain as a side effect of duloxetine, it is recognized that some patients may experience generalized aches or specific muscle discomfort while taking the medication. If you're experiencing heart-related symptoms or persistent muscle pain while taking Cymbalta, you should contact your healthcare provider immediately. Don't stop taking Cymbalta suddenly as this can cause withdrawal symptoms. Your doctor might consider adjusting your dose, switching medications, or implementing strategies to manage these side effects while maintaining your treatment for depression or anxiety.

From the FDA Drug Label

Cardiac Disorders — Frequent: palpitations; Infrequent: myocardial infarction, tachycardia, and Takotsubo cardiomyopathy. Laboratory Changes in Adults Duloxetine delayed-release capsules treatment in placebo-controlled clinical trials across approved adult populations, was associated with small mean increases from baseline to endpoint in ALT, AST, CPK, and alkaline phosphatase; General Disorders and Administration Site Conditions — Frequent: chills/rigors; Infrequent: falls, feeling abnormal, feeling hot and/or cold, malaise, and thirst; Rare: gait disturbance Musculoskeletal and Connective Tissue Disorders — Frequent: musculoskeletal pain; Infrequent: muscle spasms and myalgia

Duloxetine (Cymbalta) may cause cardiac complications, as evidenced by the following adverse reactions:

• Palpitations (frequent)
• Myocardial infarction (infrequent)
• Tachycardia (infrequent)
• Takotsubo cardiomyopathy (infrequent)
• Increased systolic blood pressure and diastolic blood pressure
• Increased heart rate

Duloxetine (Cymbalta) may also cause myalgia, as evidenced by the following adverse reactions:

• Musculoskeletal pain (frequent)
• Muscle spasms (infrequent)
• Myalgia (infrequent) 2

From the Research

Cardiac Complications

• Duloxetine may increase the risk of cardiac complications, as it can raise heart rate and diastolic blood pressure 3
• A meta-analysis found that duloxetine increased heart rate by 2.22 beats/min and diastolic blood pressure by 0.82 mmHg 3
• However, a retrospective cohort study found that the rate of acute myocardial infarction, stroke, and out-of-hospital mortality among new users of duloxetine was comparable to those who initiated gabapentin 4

Myalgia

• There is no direct evidence to suggest that duloxetine causes myalgia, but it is used to treat chronic musculoskeletal pain 5
• A systematic review and meta-analysis found that duloxetine was effective in reducing pain levels and improving depressive symptoms in patients with chronic musculoskeletal pain 5
• Common adverse events associated with duloxetine are consistent with its pharmacology and are mainly referable to the gastrointestinal and nervous systems, but myalgia is not specifically mentioned 6

Safety and Adverse Events

• Duloxetine is generally safe and well-tolerated, with few reported serious side effects 6
• The most common adverse events associated with duloxetine are nausea, headache, and dizziness 6
• Duloxetine should not be used in combination with CYP 1A2 inhibitors or nonselective, irreversible monoamine oxidase inhibitors 6