Gabapentin is a prescription medication primarily used to manage certain types of nerve pain and seizures. It is available under various brand names, including Neurontin, Gralise, and Horizant. It is also sometimes prescribed to treat restless legs syndrome. Gabapentin works by influencing nerve activity in the brain to reduce abnormal excitement and alter pain signals.
Gabapentin and False Positive Results
Gabapentin can sometimes lead to false positive results on initial drug screenings. This happens because its chemical structure can be similar enough to certain illicit substances, causing the test to mistakenly identify it through cross-reactivity. Though not an illicit substance, gabapentin has been reported to cause false positives for several drug classes.
Gabapentin has caused false positive results for benzodiazepines on immunoassay tests. It has also interfered with tests, producing false positives for amphetamines. This interference correlated with high levels of gabapentin in the sample.
While gabapentin is not typically included in standard drug screening panels and differs structurally from many tested substances, these instances highlight the potential for inaccurate initial results. Cross-reactivity means a positive screening result does not definitively confirm an illicit substance when gabapentin has been used.
How Drug Tests Work
Drug tests typically involve two main stages: an initial screening test and a confirmatory test. Initial screening tests, often immunoassays, are designed for rapid and cost-effective detection of common drug classes or their metabolites. These tests utilize antibodies that bind to specific drug molecules or their breakdown products.
Immunoassays are known for their speed but can sometimes lack specificity, leading to cross-reactivity with substances like gabapentin that have similar chemical structures. If the initial screening returns a positive result, it is considered presumptive and does not quantify the drug concentration. Confirmatory tests are then crucial.
Confirmatory tests, such as gas chromatography-mass spectrometry (GC-MS) or liquid chromatography-mass spectrometry (LC-MS), are highly accurate and specific. These methods separate and identify individual compounds in a sample based on their unique molecular structures, effectively distinguishing gabapentin from illicit substances. GC-MS is often considered the “gold standard” for forensic substance identification due to its high specificity and accuracy.
What to Do If Concerned
If you take gabapentin and anticipate a drug test or receive a false positive, several steps can be taken. Disclose your gabapentin use to the testing facility or employer before the test. Providing documentation, such as a valid prescription or a doctor’s note, can help clarify your medication use.
If an initial positive screening result occurs, request a confirmatory test, such as GC-MS or LC-MS. These advanced tests can accurately identify gabapentin and rule out illicit drugs. You also have the right to engage with a Medical Review Officer (MRO), who can verify legitimate prescriptions and interpret results in the context of your medical history.
Continue taking gabapentin as prescribed and do not discontinue it without consulting your healthcare provider. Abruptly stopping gabapentin can lead to withdrawal symptoms or worsening of the condition it treats. Open communication with medical professionals and testing personnel is key to resolving any potential misunderstandings.