Will bupropion (Wellbutrin) test positive for cocaine in a standard drug test?

Bupropion Can Test Positive for Cocaine on Standard Drug Screens

Bupropion can cause false-positive results for amphetamines or cocaine on standard urine immunoassay screening tests due to lack of specificity of these screening methods. 1

Why False Positives Occur

• Standard urine drug screens typically use immunoassays that, while sensitive, are susceptible to cross-reactions resulting in false-positive results 2
• Bupropion's chemical structure shares similarities with stimulants, which can trigger positive results on preliminary screening tests 1
• The FDA drug label specifically warns that "false-positive urine immunoassay screening tests for amphetamines have been reported in patients taking bupropion" 1

Clinical Implications

• False-positive results can have serious consequences in clinical settings, potentially leading to inappropriate treatment decisions or unwarranted suspicion of substance misuse 2
• This cross-reactivity is particularly relevant in settings where bupropion is prescribed for:
  • Depression treatment 3
  • Smoking cessation 3
  • ADHD management 3
• Some patients with previous cocaine use have reported cocaine-like sensations when taking bupropion, suggesting pharmacological similarities that may contribute to cross-reactivity on tests 4

Confirmation Testing

• When unexpected positive results occur for cocaine or amphetamines in a patient taking bupropion, confirmatory testing is essential 1
• Confirmatory tests using gas chromatography/mass spectrometry (GC/MS) can distinguish bupropion from cocaine and amphetamines 1
• The FDA label explicitly states: "Confirmatory tests, such as gas chromatography/mass spectrometry, will distinguish bupropion from amphetamines" 1

Recommendations for Clinical Practice

• Always inform patients taking bupropion about the possibility of false-positive drug test results 2
• Document bupropion use in medical records to help interpret unexpected drug test results 2
• When drug testing is required for patients on bupropion:
  • Request specific confirmatory testing if initial screening is positive 1
  • Communicate with the laboratory about the patient's medication regimen 5
  • Consider discussing unexpected results with a toxicologist 5

Important Caveats

• False-positive results may persist even after discontinuation of bupropion therapy 1
• The consequences of false-positive results can be severe in some contexts, such as employment screening, legal situations, or substance use monitoring programs 3
• Establishing a working relationship with your local toxicology laboratory can facilitate proper interpretation of results 5