According to an article in the journal Clinical Therapeutics, the duration of action of cyclobenzaprine hydrochloride is four to six hours. The medication relaxes muscles and is used in treating muscle spasms and extendi... More »

The effects of Juvederm last between 9 and 12 months, according to WebMD. How long the treatment lasts depends on a number of factors. More » Health

The shingles vaccine is effective for about six years, and possibly longer, according to the Centers for Disease Control and Prevention. As of 2015, studies are underway to determine the exact length of time the shingles... More » Health Conditions & Diseases Skin Conditions

A pill imprinted with "V" on one side and 2632 on the other indicates cyclobenzaprine hydrochloride, according to The pill is most commonly used to treat muscle spasms. More »

A single dose of Diphenhydramine hydrochloride, commonly known as Benadryl, is active in the body for between four and six hours on average. The drug is almost completely excreted from the body within 24 hours, as explai... More »

According to, the standard adult dosage for oral preparations of Demerol (meperidine hydrochloride) is between 50 and 150 milligrams, given every four to six hours. For children, the dose is calculated accordin... More » Health Medications & Vitamins

The duration of an adrenaline surge varies by the individual as well as the type of stress causing the alarm within the body, explains HowStuffWorks. If the adrenaline surge comes from seeing a cat stuck up in a tree, th... More »