Contrave is a prescription weight-management medication that combines two active ingredients: naltrexone and bupropion [1.7.3]. While effective for its intended purpose, a significant concern for individuals undergoing employment or medical screening is its potential to affect drug test results. The primary issue stems from one of its components, bupropion, which has a known history of causing false positives [1.8.2].
Understanding Contrave's Components
To understand why Contrave can trigger a positive drug screen, it's essential to look at its two active ingredients and their mechanisms of action.
Bupropion
Bupropion is classified as an aminoketone antidepressant and is also used for smoking cessation [1.7.5]. It works by inhibiting the reuptake of norepinephrine and dopamine, two key neurotransmitters in the brain [1.7.3]. Its chemical structure, however, bears a resemblance to amphetamines. This structural similarity is the main reason it can interfere with certain types of drug tests [1.4.4].
Naltrexone
Naltrexone is an opioid antagonist used to treat opioid and alcohol use disorders [1.7.2]. It works by blocking opioid receptors in the brain, which negates the effects of opioid drugs [1.7.3]. While naltrexone itself is not an opioid, there have been rare instances and anecdotal reports of it or its metabolites causing false positives on some screens for opiates or oxycodone, likely due to structural similarities [1.5.1, 1.5.6]. However, this is considered much less common than the issue with bupropion [1.2.2].
The Core Question: Can Contrave Cause a Failed Drug Test?
Yes, Contrave can cause a false-positive result on a urine drug screen, specifically for amphetamines [1.2.1, 1.3.6]. This is a well-documented interaction.
Bupropion and False Positives for Amphetamines
Numerous studies and FDA labels confirm that bupropion can lead to false-positive urine tests for amphetamines [1.4.1, 1.4.6]. The issue lies with the initial screening method used by most labs.
- Initial Screening Tests (Immunoassays): These tests are fast and inexpensive but lack high specificity [1.4.1]. They use antibodies to detect the general shape of a drug molecule. Because the metabolites of bupropion are structurally similar to amphetamines, they can cross-react with the test's antibodies, triggering a positive result [1.4.4]. One study noted that therapeutic use of bupropion was a frequent cause of false-positive amphetamine screens [1.4.4].
- Confirmatory Tests (GC-MS/LC-MS): If an initial screen is positive, a second, more definitive test should be performed. Gas Chromatography-Mass Spectrometry (GC-MS) or Liquid Chromatography-Mass Spectrometry (LC-MS) are highly specific methods that separate molecules by their precise mass and chemical properties. These tests can accurately distinguish between bupropion metabolites and actual amphetamines, and will correctly identify the initial result as a false positive [1.4.1].
Comparison Table: Contrave Components and Drug Test Interactions
| Feature | Bupropion | Naltrexone |
|---|---|---|
| Drug Class | Aminoketone Antidepressant [1.7.5] | Opioid Antagonist [1.5.2] |
| Primary False Positive Risk | Amphetamines [1.2.1] | Opiates/Oxycodone (uncommon) [1.5.1, 1.5.4] |
| Test Type Affected | Immunoassay (IA) Screens [1.4.4] | Immunoassay (IA) Screens [1.5.2] |
| Confirmatory Test Result | Will be negative for amphetamines [1.4.1] | Will be negative for illicit opioids [1.5.4] |
What To Do if You Have a Positive Test While on Contrave
Receiving a positive drug test result can be alarming, but there is a standard process to address false positives caused by prescription medication.
- Disclose Your Medications: The most crucial step is to be proactive. Inform the testing facility and the Medical Review Officer (MRO) of all prescription medications you are taking, including Contrave, before the test if possible [1.2.1, 1.8.3].
- Request Confirmatory Testing: If the initial screen comes back positive, insist on a confirmatory test like GC-MS. This is the standard procedure to verify a positive result and will differentiate bupropion from amphetamines [1.9.4].
- Provide Proof of Prescription: A Medical Review Officer (MRO), who is a licensed physician, will contact you to discuss any positive results [1.9.2]. You will have the opportunity to provide proof of your valid prescription for Contrave. The MRO will then verify the prescription with the pharmacy or prescribing doctor [1.9.3].
- Verification by MRO: Once the MRO validates your prescription and determines it is the cause of the positive screen, they will report the final result to the employer as negative [1.9.5].
Conclusion
The concern over failing a drug test while taking Contrave is valid, but manageable. The bupropion component is known to cause false positives for amphetamines on initial immunoassay screens due to structural similarities. The naltrexone component poses a much lower, but still possible, risk of interacting with opiate screens. The key is the two-step testing process. A highly specific confirmatory test (GC-MS/LC-MS) will ultimately clear a false positive. By proactively disclosing your prescription to the testing administrator or MRO and understanding your rights, you can effectively manage and resolve any issues that arise from a false-positive screen.
For more information from the manufacturer, you can visit the official CONTRAVE® HCP website.
