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, a generic variety of the medication cyclobenzaprine, is a muscle relaxer that is usually prescribed for the short-term relief of muscle spasms. Flexeril is also sometimes used for long-term conditions such as chronic fatigue syndrome and fibromyalgia. Flexeril users commonly experience drowsiness, fatigue, nausea, muscle weakness, dry throat or mouth, appetite loss, diarrhea and gas while taking the medication.