What Medications Test Positive for Methamphetamines? Understanding False Positives

Drug tests are widely used to check for illegal substances, but false positives can sometimes happen. These occur when the test detects a substance that mimics the chemical structure of illegal drugs, leading to incorrect results. If you’ve ever wondered, “What can make you test positive for methamphetamines?” or “What medications test positive for methamphetamines?” — this guide has the answers you need, with a specific focus on Australian contexts.

Understanding False Positives

False positives occur because many drug tests, especially initial screenings like immunoassays, are designed to detect drug classes rather than specific substances. These tests can’t always differentiate between similar compounds, which is why confirmatory testing, such as gas chromatography-mass spectrometry (GC-MS), is crucial to verify results.

Key Factors That Can Lead to False Positives

• Cross-reactivity: When substances with similar structures react with the test.
• Metabolization: Some medications are metabolized into compounds that resemble amphetamines or methamphetamines.
• Environmental exposure: Passive exposure to drugs or contamination.
• Cut-off levels: If the concentration of a substance exceeds the test’s cut-off level, it may trigger a false positive.

Drug Testing Standards in Australia

In Australia, drug testing is regulated by the Australian Standard AS/NZS 4308:2008, which sets guidelines for drug testing in urine samples. This standard is widely used in workplaces, particularly in industries such as mining, construction, and transportation, as well as in pre-employment screening and law enforcement roadside drug testing.

Medications That Can Cause False Positives for Methamphetamines

Several prescription and over-the-counter medications can lead to false positives for amphetamines or methamphetamines. Below are the most common examples:

• Pseudoephedrine: Found in cold and allergy medications like Sudafed and Codral.
• Ephedrine: Used in asthma and nasal decongestants.
• Phentermine: A weight loss medication.
• Dexamphetamine: Commonly prescribed for ADHD.
• Bupropion: Used for depression and smoking cessation.
• Selegiline: A treatment for Parkinson’s disease.
• Trazodone: An antidepressant.
• Quetiapine: An antipsychotic.
• Phenylephrine: Found in decongestants like Dimetapp and some Codral formulations.

Other medications, including designer drugs and stimulants like cathinones, can also trigger a positive result. These medications may metabolize into compounds that resemble amphetamines or methamphetamines, which can lead to detection in drug tests.

Foods and Substances That Might Cause False Positives

While there are no specific foods identified as causing false positives for methamphetamines, it’s helpful to understand how other substances can interfere with drug tests:

• Poppy seeds: Contain trace amounts of morphine and codeine, which can trigger a positive result for opiates. This includes common Australian bakery items like poppy seed bread.
• Hemp seeds: May result in a false positive for THC (marijuana). These are sometimes found in health foods and smoothies in Australia.
• Coca tea: Made from the coca plant, it can cause a positive result for cocaine. This product is illegal in Australia but may be brought in by travelers.
• Tonic water: Contains quinine, which may result in a false positive for opiates.
• Pizza and durian: These can cause false positives on alcohol breath tests but are unrelated to methamphetamines.

Environmental Factors

Passive drug exposure or contamination can also lead to false positives. For example, secondhand smoke from methamphetamines or handling drug-laced objects might result in detection during a test.

How to Minimize the Risk of False Positives

If you’re undergoing a drug test, here are some steps to reduce the risk of misinterpretation:

1. Inform the testing facility about all prescription and over-the-counter medications you’re taking, especially those commonly available in Australia, such as Sudafed or Codral.
2. Avoid consuming foods known to interfere with drug tests, such as poppy seeds or hemp products, before testing.
3. Request confirmatory testing if you suspect a false positive result.

Roadside Drug Testing in Australia

Australian police frequently conduct Mobile Drug Testing (MDT) on drivers to detect substances such as methamphetamines. If a false positive occurs during roadside testing, you can request further testing at a medical facility to confirm the result. It is crucial to disclose any medications you are taking to avoid legal complications.

What to Do If You Test Positive

If you receive a positive drug test result, here’s what you should do:

1. Request confirmatory testing: Tests like GC-MS can accurately identify substances and rule out false positives.
2. Provide documentation: Share a list of all medications, supplements, and dietary habits with the testing facility.
3. Discuss further action: Work with your healthcare provider or employer to clarify the situation.

Medications That May Cause False Positives for Amphetamines

Below is a table of medications that are known to potentially cause false positives for amphetamines or methamphetamines:

By understanding which medications and factors can lead to false positives, you’ll be better prepared to navigate the complexities of drug testing in Australia. Always disclose your medications and request additional testing if needed to ensure accurate results.