I've never taken either one of those but I got this off of a website in the off chance that it may be of a little help.

SOMA:

Carisoprodol, a muscle relaxant, is used with rest, physical therapy, and other measures to relax muscles and relieve pain and discomfort caused by strains, sprains, and other muscle injuries.

Although side effects from carisoprodol are not common, they can occur. Tell your doctor if any of these symptoms are severe or do not go away:

* drowsiness
* dizziness
* clumsiness
* headache
* fast heart rate
* upset stomach
* vomiting
* skin rash

If you experience any of the following symptoms, call your doctor immediately:

* difficulty breathing
* fever
* weakness
* burning in the eyes

FLEXERIL:

What is cyclobenzaprine?
• Cyclobenzaprine is a muscle relaxant. It works by blocking nerve impulses (or pain sensations) that are sent to your brain.
• Cyclobenzaprine is used to relieve pain, tenderness, and limitation of motion caused by muscle spasms. It is used, along with rest and physical therapy, for short-term treatment (i.e., 2 to 3 weeks).
• Cyclobenzaprine may also be used for purposes other than those listed in this medication guide.

•If you experience any of the following serious side effects, stop taking cyclobenzaprine and seek emergency medical attention:
·an allergic reaction (difficulty breathing; closing of your throat; swelling of your lips, tongue, or face; or hives);
· seizures, hallucinations, or confusion;
· blurred vision;
· increased heart rate; or
· depression.
•Other, less serious side effects may be more likely to occur. Continue to take cyclobenzaprine and talk to your doctor if you experience
· drowsiness or dizziness;
· dry mouth or a bad taste in your mouth;
· insomnia;
· difficulty urinating; or
· sweating.
•If you stop taking this medication suddenly, you may experience some withdrawal effects.
•Side effects other than those listed here may also occur. Talk to your doctor about any side effect that seems unusual or that is especially bothersome

Hope this wasn't too reiterative.