Brief Answer:
Some similarities

Detailed Answer:
Hello and welcome to Ask A Doctor service.

I have reviewed your query and here is my advice.

Flexeril is similar to an anti-depressant amitryptiline but its mainly used as muscle relaxant e.g in fibromyalgia. Its used for muscle stiffness, pains, sleep problems.

Cymbalta also has similar profile. It has been mainly used as anti-depressant but also is used for muscle stiffness, pain syndromes, sleep problems, anxiety disorder.

So their effects and side effects can add-up to some extent.

Hope this helps. Let me know if I can assist you further.
Dr Vaishalee

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