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 Use in Pregnancy and Breastfeeding (Cyclobenzaprine) Flexeril is used as a muscle relaxing agent in the treatment of different spastic muscular disorders. Its primary component is cyclobenzaprine and this drug is widely prescribed for it safe and efficacious use. Muscle disorders can occur in pregnant women and in those who are breastfeeding. Obviously, in such cases, there is a concern about the use of any drug and Flexeril is no exception.