Can Cyclobenzaprine (Flexeril) show up on a drug test?
By
Dr Natalia Marceli Stephanes (PhD)
Author bio
Dr Natália Marcéli Stephanes PhD is a Pharmacist with expertise in Drugs Administration and Toxicity; Discovery of New Drugs; Cancer Treatment; Biochemical Analyzes and Hematological Analyzes. She writes and reviews content on these topics.
Dr Natália Marcéli Stephanes’ Highlights:
- Pharmacist at the Department of Health of Santa Catarina State, Brazil
- PhD with a focus on oncology treatment
- Years of experience in commercial pharmacy
- Bachelor, Master and PhD degrees in Pharmacy at the Federal University of Santa Catarina
Professional Experience:
From her undergraduate studies to her Master’s and Doctorate degrees in Pharmacy, Dr Natália Marcéli Stephanes has participated in numerous scientific studies in the field of oncology and onco-hematology at the University Hospital of the Federal University of Santa Catarina, Brazil. Her research has focused on understanding the molecular and biochemical bases of malignant neoplasms and investigating safer and more effective therapeutic alternatives.
Dr Natália Marcéli Stephanes has also served as an assistant professor of haematology for undergraduate students at the Federal University of Santa Catarina. Additionally, she held the position of professor of Hospital Pharmacy at the Qualificar Technical School in Brazil, where she developed instructional materials for use in the Pharmacy Postgraduate Program at the Leonardo Da Vinci University Center.
In addition to her academic experiences, Dr Natália Marcéli Stephanes possesses a strong expertise in commercial pharmacy, with in-depth knowledge of medications, their routes of administration, desired effects, adverse effects, and toxicity.
Currently, Dr Natália Marcéli Stephanes works as a Pharmacist at the Health Department of Santa Catarina State, where her role entails providing pharmaceutical scientific consulting services to judges.
Education:
- 2016 Bachelor in Pharmacy at the Federal University of Santa Catarina, Brazil
- 2018 Master in Pharmacy at the Federal University of Santa Catarina, Brazil
- 2023 PhD in Pharmacy at the Federal University of Santa Catarina, Brazil
The main publications of Dr Natália Marcéli Stephanes are:
Falchetti M ; Delgobo M, Zancanaro H, Almeida K, Das Neves RN, Dos Santos B, Stefanes NM, et al. Bishop Omics-based identification of an NRF2-related auranofin resistance signature in cancer: Insights into drug repurposing. Comput. Biol. Med [Internet]. 2023; 152:106347.
Feuser PM, Matos dos Santos PC, Cordeiro AP, Stefanes NM, Walter LO, Maioral MF, Santos-Silva MC, et al. Antineoplastic activity of free 4-nitrochalcone and encapsulated in poly(thioether-ester) nanoparticles obtained by thiol-ene polymerization in two human leukemia cell lines (Jurkat and K562). J Drug Deliv Sci Technol [Internet]. 2022; 67:102924.
Jacques AV, Stefanes NM, Walter LO, Perondi DM, Efe FL, Souza LFS, Sens L, et al. Synthesis of chalcones derived from 1-naphthylacetophenone and evaluation of their cytotoxic and apoptotic effects in acute leukemia cell lines. Bioorg. Chem [Internet]. 2021; 116:105315.
Duarte BF, Vieira DSC, Lisboa ML, Stefanes NM, Grando LJ, Santos-Silva MC. Características clínico-epidemiológicas de pacientes portadores de carcinoma de células escamosas de boca. Arquivos Catarinenses de Medicina. 2021; 50(2): 232–245.
Machado V, Jacques AV, Stefanes NM, Santos-Silva MC, Biavatti MW. Anti-leukemic activity of semisynthetic derivatives of Lupeol. Nat. Prod. Res. 2021; 35(22):4494-4501.
Bigolin A, Maioral MF, Stefanes NM, Mascarello A, Chiaradia-Delatorre LD, Nunes RJ, Yunes RA, et al. A novel sulfonamide derivative as a strong and selective apoptotic agent against hematological malignancies. Chem. Pap. 2020; 74:2965–2976.
Bigolin A, Maioral MF, Stefanes NM, Zatelli GA, Philippus AC, Falkenberg MB, Santos-Silva MC. Cytotoxic mechanisms of primin, a natural quinone isolated from Eugenia hiemalis, on hematological cancer cell lines. Anticancer Drugs. 2020; 31(7):709-717.
Maioral MF, Stefanes NM, Neufeldt PD, Chiaradia-Delatorre LD, Nunes RJ, Santos-Silva MC. Aldehyde biphenyl chalcones induce immunogenic apoptotic-like cell death and are promising new safe compounds against a wide range of hematologic cancers. Future Med. Chem. 2020; 12(8):673–688.
Perondi DM, Jacques AV, Stefanes NM, Maioral MF, Sens L, Pacheco LA, Cury NM, et al. A novel thiosemicarbazone as a promising effective and selective compound for acute leukemia. Anticancer Drugs. 2019; 30(8):p 828-837.
Rengifo AFC, Stefanes NM, Toigo J, Mendes C, Argenta DF, Dotto MER, Santos-Silva MC, et al. PEO-chitosan nanofibers containing carboxymethyl-hexanoyl chitosan/dodecyl sulfate nanoparticles loaded with pyrazoline for skin cancer treatment. Eur. Polym. J. 2019; 119:335-343.
Rengifo AFC, Stefanes NM, Toigo J, Mendes C, Santos-Silva MC, Nunes RJ, Parize AL, et al. A new and efficient carboxymethyl-hexanoyl chitosan/dodecyl sulfate nanocarrier for a pyrazoline with antileukemic activity. Mater. Sci. Eng. C [Internet]. 2019; 105:110051.
Maioral MF, Stefanes NM, Bigolin A, Zatelli GA, Philippus AC, Falkenberg MB, Santos-Silva MC. Miconidine acetate, a new selective and cytotoxic compound with synergic potential, induces cell cycle arrest and apoptosis in leukemia cells. Invest. New Drugs. 2019; 37:912–922.
Srefanes NM, Toigo J, Maioral MF, Jacques AV, Chiaradia-Delatorre LD, Perondi DM, Ribeiro AAB, et al. Synthesis of novel pyrazoline derivatives and the evaluation of death mechanisms involved in their antileukemic activity. Bioorg. Med. Chem. 2019; 27(2):375-382.
Maioral MF, Bodack CN, Stefanes NM, Bigolin A, Mascarello A, Chiaradia-Delatorre LD, Yunes RA, et al. Cytotoxic effect of a novel naphthylchalcone against multiple cancer cells focusing on hematologic malignancies. Biochim. 2017; 140:48-57.
You can view some of Dr Natália’s work below and links to her professional profile below.
Research Gate: https://www.researchgate.net/profile/Natalia-Stephanes
Linkedin: https://www.linkedin.com/in/nataliamarceli/
Can Cyclobenzaprine (Flexeril) show up on a drug test?
No, Cyclobenzaprine (Flexeril) does not show up on the standard drug urine immunoassay. However, it will show up if the test is specifically done to check the presence of Cyclobenzaprine.
This medication is a muscle relaxant and is not recommended to be used for more than 10 days. Now, Cyclobenzaprine is not a substance of abuse and will not show up on a general drug testing procedure.
The medication is also not known to cause a false positive or make you fail a drug test. However, if you’re being checked for Cyclobenzaprine, it will definitely show up.
How long does Cyclobenzaprine stay in your system?
Cyclobenzaprine has a long half-life and it stays in your system for about 18-24 hours, but it can go as high as 37 hours in some people (1).
Because of the longer half-life, Cyclobenzaprine can take 4 to 8 days to leave your system completely and it is detectable in urine tests during this time period.
If you’re on standard doses, the drug will definitely not show up and if you’re taking a prescription medication, you don’t need to worry about it.
However, if you’re overusing the medication – it will still not show up on a drug test, but there is no way to be certain. Make sure you only take as much Cyclobenzaprine as prescribed by your healthcare provider.
Cyclobenzaprine and other muscle relaxants like Methocarbamol can be used for muscle pain, but these medications can not help with other kinds of pain, like dental pains. So, make sure you are using the medication for the right reasons.
How to generally prevent getting a false positive?
There are a number of medications which are known to cause false positives. The easy fix is to avoid using the culprit medication 2-3 days before the test to give your body enough time to get rid of the medication. However, not every single medication can be skipped.
There are some meds like antidepressants and antipsychotic medications that can cause a false positive but you should never stop taking these meds for the sake of avoiding a false positive.
The best way to deal with that is to talk to your healthcare provider and inform the drug testing authorities about your prescription medication that can cause a false positive. This way, getting a false positive will not affect you in any way.
However, if your testing technique is more accurate than the preliminary urine drug immunoassay, you may not get any false positives because of the accuracy of the tests.
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References
1.-
PubChem [Internet]. Bethesda (MD): National Library of Medicine (US), National Center for Biotechnology Information; 2004-. PubChem Compound Summary for CID 2895, Cyclobenzaprine; [cited 2023 Jan. 8]. Available from: https://pubchem.ncbi.nlm.nih.gov/compound/Cyclobenzaprine
