Everything we consume has a specific time to get eliminated from the body. Medicines have a process of consumption, metabolization, the actual effect and the elimination. It takes some specified half lives and time in this process.

Muscle relaxers relax muscles by blocking pain signals to the brain. It is a short-term relaxer and stays in the body for a certain period and is excreted. The duration  of muscle relaxers in the human body also depends on several factors. (A bit over the edge)

So how much time does it stay in our system? These types of doubts can help to become more aware of medicine and your health.

How Long Does Muscle Relaxers Stay in Your System?

Our body is a great network of muscle tissues, bone and complex systems. Sometimes it gets disturbed due to stiffness of muscles. Muscle relaxers are fast affecting medicine. 

The average period of muscle relaxers is from 4 to 6 hours. It is excreted through urine, however, some muscle relaxers can stay in the system for longer as the effects vary from drug to drug and person to person.

If you are consuming muscle relaxers for long-term, it can be detected for about 10 days or as you continue the dose. The half-life is a parameter to calculate the duration of drug.The effectiveness and excretion of muscle relaxers are tested through their half-life.

Carisoprodol stays for 6 hours in your system after consumption. You might wonder about the half-life concept. With half life calculation of medicine you can get to know the elimination time of any medicine. (Ballantyne, Jane C. FRCA;  September 1997).

Muscle Relaxer And Half-Life

Half-life is a powerful parameter to measure the half-elimination of life of the drug. In simple words when you consume a muscle relaxer and the half-life is about 1 hour, it states that 50% of the muscle relaxer quantity is worked out/absorbed in that one hour and the rest can be used and excreted afterward. Hence it is called Half-life.

For your understanding let's put some simple maths

Flexeril is eliminated within 5 days to 15 days. And it has a half-life of 1 to 3 days, the calculation goes like

  • 5*(Half-life): 5*1=5 days
  • 5*(Half-life): 5*3= 15 days

Half-life is calculated through observance of the dosage system. (Browning, R., Jackson, J.L. and O’Malley, P.G., 2001.)

Factors Affecting the Duration of Muscle Relaxers in the Human Body

  • Alcohol: Consumption of alcohol with muscle relaxers can increase the accommodation period in the human body.
  • Dosage: Dosage patterns can affect the elimination, dosage patterns can vary from person to person. The missed dose can affect the duration of the drug
  • Medical conditions: Medical conditions can vary in dosage and types of muscle relaxants to be used. Some relaxers have a high time to absorb.
  • Body mass: Mass of the body affects the excretion of the drug, the bigger the size the longer (What is the elimination?) will be excretion time.
  • Metabolism rate: High metabolism rate will help to excrete out drugs    quickly and vice versa.

Muscle Relaxers and Their Duration of Elimination

Generic Name

Brand Name

Elimination time



  11 Hour



8 days



24 hours



4 hours



1 ½ hours

We hope your doubts are clear.


Generally, the average life of a muscle relaxer in your system is about 4 to 6 hours and then it is thrown out of your system. Muscle relaxers are used for the short term and also in chronic pain. Hope you learned about the half-life of drugs. You also learned various factors can affect the elimination time of drugs in your system.


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