Do muscle relaxers show up on a drug test

Countless of people are asking: How long do muscle relaxers stay in your system? If you’re one of these individuals, you may be asking this question because you’re scheduled for a drug test, and you don’t want to test positive. Muscle relaxers can be a godsend, especially if you’re lifestyle includes rigorous physical activities. However, excessive use of this product can eventually take a toll on your health.

This is because some muscle relaxants could mimic the reaction of tricyclic antidepressants. This will generally test positive in a drug test. This means that when you take too many muscle relaxants or become too dependent on it, your drug test will show that you’ve been using some kind of anti-depressant. In this case, if you come up positive for tricyclic antidepressants, it would be a minus factor for you, especially if you’re in search of employment.

The positive result will indicate that you are prone to depression. An employer will not hire someone, who has the tendency to become depressed. An employee who’s emotionally unstable can eventually become a liability to the business, not an asset. Employers would always choose to hire individuals who are mentally and physically healthy, and you wouldn’t be able to fit this qualification if you tested positive in a drug test.

Therefore, you must know how long the muscle relaxer stays in your system, so you could adjust your job hunting accordingly. This information will help determine when you should stop using muscle relaxants and what you should do to ensure that this product will not become the reason why you’ll have a positive drug test. This is most especially applicable if you’re on medication with drugs causing muscle relaxation.

Must Read: How Long Does Alcohol Stay In Your System

Here’s a video about muscle relaxants:

How Long Do Muscle Relaxers Stay in Your System?

The Influencing Factors

The hidden truth is that there are various factors that affect the elimination of the drug from your body. These are:

  1. Concentration of The Drug Administered

Additionally, the concentration of the drug taken in must also be considered. The higher the concentration of the drug administered, the longer it stays in your system. If you plan to undergo a drug test soon, make sure to stop using any type of muscle relaxer as soon as possible. Time is of the essence to ensure that the compounds that are found in muscle relaxers will not be found in your body during the drug test.

  1. Detoxifying and Metabolizing Function of Your Liver

The major functions of the liver are to detoxify and metabolize drugs that enter your body. Thus, if your liver is impaired, the drug will have a long time being metabolized and detoxified, and thus may remain in your system longer than normal.

For you to know whether your kidney is still functioning or not, consider talking to your doctor about it. Aside from your body’s ability to flush out muscle relaxers, the condition of your kidney will also affect your chances of securing a job in the future.

  1. Ability of Your Kidney to Eliminate The Drug and Its Metabolites

Likewise, the major function of the kidneys is to eliminate waste products of metabolism and unwanted toxic substances from your body.

Consequently, when you have an impaired or dysfunctional kidney, drugs that enter your body will have difficulty being excreted, and will remain in your system longer than normal.

  1. Weight of The Person

The body mass of the person has to be considered too. The greater the weight or body mass, the quicker the drug can be eliminated from the system.

  1. Age and Sex

The speed of elimination of drugs in the elderly is decreased. So, if you’re 50 and above, you should expect a slower elimination of the drug. This is due to the fact that your organs are already ‘old’; you have less efficient organs. Thus, the drug will stay in your system longer.

Usually, males have larger body mass, so the drug is more quickly eliminated from their systems than in women.

  1. Frequency and Length of Drug Intake

The frequency and length of intake has also an effect on how long the drug stays in your system.

A person, who takes the drug 3 times a day for 5 days, will eliminate the drug more slowly, than a person, who has taken it once a day for 2 days only.

  1. Presence of Drugs That can Interact with The Muscle Relaxer

There are certain drugs that can prevent the elimination of muscle relaxer drugs, so they stay longer in your system. These can be CYP3A4 inhibitors, such as Ritonavir and Chloramphenicol.

The points mentioned in this article should be enough for you to gradually minimize and stop the use of muscle relaxers. Instead of using this product, opt to look for natural supplements, such as herbs or hemp oil. These products don’t leave any residue in your blood that can lead to a positive drug test.

Aside from relaxing your muscles, these natural supplements can also provide several other health benefits, such as mental wellness and stress relief.

Specific Instances That You Must Know

How long do muscle relaxers stay in your system

Normal person with intermittent intake of drug (after discontinuance)

In normal persons, without organ impairment, and intermittent intake of muscle relaxers (Examples are Valium, Robaxin, Flexeril and Skelaxin); the drug will stay in your systemic circulation for 5 to 14 days after last dose. Take note that in this case, the intake is intermittent.

The half-life of Flexeril is typically 18 hours, but it’s eliminated from your system after around 36 to 42 hours.

Normal person, who are fast metabolizers (after discontinuance)

The drug can be cleared in systemic circulation within a period of 48 to 72 hours. But, to be sure, you may want to extend the number of days, so that the muscle relaxer will be completely excreted from your body.

You have to discontinue completely, the drug as well. Also, hydration could help significantly in eliminating the drug from your system.

Water is a universal solvent, so it can aid your organs in ‘washing’ away drugs that have entered your body. You should drink more than 8 glasses of water per day.

Persons with hepatic and renal dysfunction (after discontinuance)

The elimination of drug is prolonged, so it stays in your system longer than normal. You can expect the drug to stay around 8 to 37 days. This will also depend on the severity of the dysfunction. The more severe the impairment, the longer the drug could be eliminated.


I have answered the question: How long do muscle relaxers stay in your system? As discussed, there are multifarious factors that affect its elimination, so there are many answers. The answer depends on what category you belong to.

Evaluate your body’s physiologic status and determine how many hours will the muscle relaxer stay in your system. Remember to consider all the factors involved.

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