frameshift mutation / frame-shift mutation; frameshift. A frameshift mutation is a genetic mutation caused by a deletion or insertion in a DNA sequence that shifts the way the sequence is read. A DNA sequence is a chain of many smaller molecules called nucleotides.
As for Flexeril (cyclobenzaprine) is is not a controlled substance under US, Canadian, or international law. Some drugs used as muscle relaxants ARE controlled substances like Valium and many US states and countries have listed Soma (carisoprodol) as a controlled substance (or prohibited it).
Flexeril (cyclobenzaprine) is a muscle relaxant. It works by blocking nerve impulses (or pain sensations) that are sent to your brain. Flexeril is used together with rest and physical therapy to treat skeletal muscle conditions such as pain or injury. Flexeril may also be used for other purposes not listed in this medication guide.