Shldr neck muscle pain. have 10mg flexeril (cyclobenzaprine hcl). how long to feel relief other than just being sleepy? i take 1/4-1/2 tablet at bedtime

1-2 hours.: The time that it takes to work will depend upon the specific situation. It is absorbed rather quickly, so will have some benefit within the first 1-2 hours. When used for acute treatment of muscle spasm, it is usually prescribed to be taken three times per day, because the effect may wear off within 8-12 hours, even though the drug has a long half-life (an average of 18 hours).