How Long Do Benzodiazepines Stay in Your System?

Centrax is a brand-name prescription benzodiazepine, which is also known as prazepam in its generic form. As with other benzodiazepines, Centrax is considered to be a sedative drug that depresses the central nervous system. Centrax affects GABA, a calming neurotransmitter, increasing its effects and creating a feeling of calm and tranquility. Benzodiazepines like Centrax are only intended as short-term medications. All benzodiazepines, or “benzos,” such as Centrax are considered to be habit-forming. That risk of substance use disorder makes them ill-suited as long-term treatment medications. As Centrax affects the GABA neurotransmitter, the drug can also trigger a dopamine response. That dopamine response can trigger reward responses in the brain, which can lead to substance use disorder.

Benzodiazepines all have very similar mechanisms of action. Where they differ, however, is in how quickly they take effect and how long the effects last. Some benzodiazepines have a short onset of action, meaning that once someone takes the drug, it starts affecting them quickly. This rapid onset of action makes certain benzos more addictive than others. The quicker a drug starts working, the more addictive it may be. There are also benzodiazepines that are short-acting or long-acting. This refers to how long they remain in the system and work. Some benzodiazepines last only a few hours, while others can provide effects for days. Longer-acting benzodiazepines tend to accumulate in the system.

How Long Does Centrax (Prazepam) Stay in the System?

People often wonder how long Centrax stays in the system, particularly if they have to take a drug test. Benzodiazepines, in general, can show up on a urine test anywhere from 2-28 days after the last dose. There is a large variance based on the specific benzodiazepine used, the amount taken, and individual factors such as metabolism. People might also wonder how long Centrax remains in the system to anticipate when withdrawal symptoms will begin to surface. Knowing the onset of action and how long Centrax stays in the system can also help people understand how addictive the drug is.

Centrax is one of the longest-lasting benzodiazepines available, with an active metabolite half-life of 29 to 224 hours. This means that it could take more than 400 hours to fully eliminate one specific metabolite left behind by the drug. Many drug tests are designed to screen for metabolites of parent drugs, which often remain much longer.

Since Centrax leaves behind a metabolite that can stay in the body for so long, this drug may show up on a drug test for much longer than most other substances. Centrax also starts working very quickly. Its onset of action is about 30 minutes and the duration of the effects last around 12 hours. It is likely that Centrax will accumulate in the system, so it is especially dangerous to mix the drug with opioids, alcohol or other central nervous system depressants.

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Medical Disclaimer

The Recovery Village aims to improve the quality of life for people struggling with substance use or mental health disorder with fact-based content about the nature of behavioral health conditions, treatment options and their related outcomes. We publish material that is researched, cited, edited and reviewed by licensed medical professionals. The information we provide is not intended to be a substitute for professional medical advice, diagnosis or treatment. It should not be used in place of the advice of your physician or other qualified healthcare providers.