Medications That May Affect Your Drug Test
Some prescription and over-the-counter medications can cause a non-negative result on an immunoassay drug screen. Use the search below to check any medication you are taking before your appointment.
Upload DocumentationWhat Is a Non-Negative Result?
Drug screening tests used at collection sites are immunoassay tests. They are fast and cost-effective, but designed to be sensitive — meaning they can sometimes react to substances other than the drug being screened for. This is called a non-negative or presumptive positive result. It does not automatically mean you have used an illegal substance.
Why Do Medications Cause This?
Many prescription and over-the-counter medications share a similar chemical structure to controlled substances. When the immunoassay antibody encounters these medications, it may react as though a controlled substance is present — a phenomenon known as cross-reactivity. Confirmatory testing (GC-MS or LC-MS) is highly specific and will distinguish between a legitimate medication and an illicit substance.
What Should You Do?
If your drug test result is non-negative, a Medical Review Officer (MRO) will contact you directly. Prepare your proof — prescription label, physician letter, or pharmacy dispensing records — and upload your documentation securely through this portal before or after your MRO interview to help expedite the process.
Upload your documentation →Medications Grouped by Drug Class
The following tables list common prescription and non-prescription medications that have been documented to cause cross-reactive (non-negative) results on immunoassay drug screens. This list is not exhaustive. If you are taking a medication not listed here, please upload your documentation through the secure portal or contact your MRO directly.
Jump to class:
Amphetamines / Methamphetamines Benzodiazepines Cannabinoids (THC) Opiates / Opioids Phencyclidine (PCP) Barbiturates Cocaine (Benzoylecgonine) Methadone LSD (Lysergic Acid Diethylamide) Tricyclic Antidepressants (TCAs) Buprenorphine
Amphetamines / Methamphetamines
Amphetamine immunoassays are particularly prone to cross-reactivity due to the phenylethylamine structure shared by many common medications. The following medications have been documented in peer-reviewed literature to cause non-negative amphetamine results.
| Medication (Generic) | Common Brand Names | Commonly Used For | Test Type |
|---|---|---|---|
| Lisdexamfetamine | Vyvanse | ADHD, binge eating disorder | Urine Oral Fluid |
| Amphetamine / Dextroamphetamine | Adderall, Adderall XR | ADHD, narcolepsy | Urine Oral Fluid |
| Dextroamphetamine | Dexedrine, Dextrostat | ADHD, narcolepsy | Urine Oral Fluid |
| Methamphetamine (prescribed) | Desoxyn | ADHD, obesity (rarely prescribed) | Urine Oral Fluid |
| Bupropion | Wellbutrin, Zyban | Depression, smoking cessation | Urine Oral Fluid |
| Trazodone | Desyrel | Depression, insomnia | Urine |
| Fluoxetine | Prozac | Depression, anxiety, OCD | Urine Oral Fluid |
| Desipramine | Norpramin | Depression | Urine |
| Doxepin | Sinequan, Silenor | Depression, insomnia, anxiety | Urine |
| Selegiline | Eldepryl, Zelapar | Parkinson's disease | Urine |
| Aripiprazole | Abilify | Schizophrenia, bipolar disorder, depression | Urine |
| Chlorpromazine | Thorazine | Schizophrenia, bipolar disorder | Urine |
| Thioridazine | Mellaril | Schizophrenia | Urine |
| Promethazine | Phenergan | Nausea, allergies, motion sickness | Urine Oral Fluid |
| Pseudoephedrine | Sudafed | Nasal congestion, colds | Urine Oral Fluid |
| Ephedrine | Bronkaid, Primatene | Nasal congestion, asthma | Urine Oral Fluid |
| Phenylephrine | Sudafed PE, Neo-Synephrine | Nasal congestion | Urine |
| Phenylpropanolamine | Formerly in Dimetapp, Robitussin CF | Nasal decongestant (withdrawn from most markets) | Urine |
| Brompheniramine | Dimetapp | Allergies, cold symptoms | Urine |
| Methylphenidate | Ritalin, Concerta, Biphentin | ADHD | Urine |
| Atomoxetine | Strattera | ADHD | Urine |
| Phentermine | Adipex-P, Lomaira | Weight management | Urine |
| Amantadine | Symmetrel | Parkinson's disease, influenza | Urine |
| Labetalol | Trandate | Hypertension | Urine |
| Mexiletine | Mexitil | Cardiac arrhythmias | Urine |
| Metformin | Glucophage | Type 2 diabetes | Urine |
| Ranitidine | Zantac (withdrawn in many markets) | Heartburn, acid reflux | Urine |
| Ofloxacin | Floxin | Bacterial infections | Urine |
| L-methamphetamine (Vicks Inhaler) | Vicks Inhaler | Nasal congestion (OTC inhaler) | Urine |
| DMAA (Dimethylamylamine) | Various pre-workout supplements | Energy/athletic performance supplement | Urine |
Benzodiazepines
Benzodiazepine immunoassays detect nordiazepam and oxazepam metabolites. Certain NSAIDs, SSRIs, and antiretrovirals have been documented to cross-react with this assay.
| Medication (Generic) | Common Brand Names | Commonly Used For | Test Type |
|---|---|---|---|
| Sertraline | Zoloft | Depression, anxiety, OCD, PTSD | Urine |
| Oxaprozin | Daypro | Pain, inflammation, arthritis | Urine |
| Fenoprofen | Nalfon | Pain, inflammation | Urine |
| Flurbiprofen | Ansaid | Arthritis, pain | Urine |
| Ketoprofen | Orudis | Pain, inflammation | Urine |
| Ibuprofen | Advil, Motrin | Pain, fever, inflammation | Urine |
| Efavirenz | Sustiva | HIV treatment | Urine |
| Diphenhydramine | Benadryl, Unisom | Allergies, sleep aid | Urine Oral Fluid |
| Hydroxyzine | Atarax, Vistaril | Anxiety, allergies | Urine |
| Promethazine | Phenergan | Nausea, allergies | Urine |
| Chlorpromazine | Thorazine | Schizophrenia, bipolar disorder | Urine |
Cannabinoids (THC)
Several NSAIDs, proton pump inhibitors, antiretrovirals, and hemp-derived products have been documented to cause cross-reactive non-negative results on THC immunoassay screens.
| Medication (Generic) | Common Brand Names | Commonly Used For | Test Type |
|---|---|---|---|
| Ibuprofen | Advil, Motrin | Pain, fever, inflammation | Urine |
| Naproxen | Aleve, Naprosyn | Pain, inflammation, arthritis | Urine |
| Sulindac | Clinoril | Arthritis, pain | Urine |
| Fenoprofen | Nalfon | Arthritis, pain | Urine |
| Dronabinol | Marinol, Syndros | Nausea (chemotherapy), appetite stimulation | Urine Oral Fluid |
| Pantoprazole | Protonix, Tecta | Acid reflux, GERD | Urine |
| Omeprazole | Losec, Prilosec | Acid reflux, GERD, ulcers | Urine |
| Esomeprazole | Nexium | Acid reflux, GERD | Urine |
| Efavirenz | Sustiva | HIV treatment | Urine |
| CBD / Hemp products | Various CBD oils, hemp foods | Wellness, pain relief (OTC) | Urine |
| Lamotrigine (synthetic cannabinoid screen) | Lamictal | Epilepsy, bipolar disorder | Urine |
Opiates / Opioids
Opiate immunoassays can react to a wide range of medications that share structural similarities with morphine and codeine. Certain antibiotics, antipsychotics, and OTC medications are well documented to cross-react.
| Medication (Generic) | Common Brand Names | Commonly Used For | Test Type |
|---|---|---|---|
| Dextromethorphan | Robitussin DM, NyQuil, Delsym | Cough suppression | Urine Oral Fluid |
| Rifampin | Rifadin | Tuberculosis, bacterial infections | Urine |
| Levofloxacin | Levaquin | Bacterial infections | Urine |
| Ofloxacin | Floxin | Bacterial infections | Urine |
| Diphenhydramine | Benadryl | Allergies, sleep aid | Urine |
| Verapamil | Calan, Isoptin | Heart conditions, hypertension | Urine |
| Quinine | Qualaquin | Malaria | Urine |
| Quetiapine | Seroquel | Schizophrenia, bipolar disorder, depression | Urine |
| Tramadol | Ultram, Zytram | Moderate to severe pain | Urine Oral Fluid |
| Tapentadol | Nucynta | Moderate to severe pain | Urine |
| Naloxone | Narcan | Opioid overdose reversal | Urine |
| Amisulpride | Solian | Schizophrenia | Urine |
| Poppy Seeds | Food source | Dietary — baked goods | Urine |
Phencyclidine (PCP)
PCP immunoassays have documented cross-reactivity with several common prescription and OTC medications, particularly antidepressants, antihistamines, and analgesics.
| Medication (Generic) | Common Brand Names | Commonly Used For | Test Type |
|---|---|---|---|
| Dextromethorphan | Robitussin DM, NyQuil | Cough suppression | Urine Oral Fluid |
| Diphenhydramine | Benadryl | Allergies, sleep aid | Urine |
| Doxylamine | Unisom SleepTabs, Diclectin | Sleep aid, morning sickness | Urine |
| Ibuprofen | Advil, Motrin | Pain, fever, inflammation | Urine |
| Tramadol | Ultram, Zytram | Moderate to severe pain | Urine Oral Fluid |
| Venlafaxine | Effexor | Depression, anxiety, PTSD | Urine |
| Imipramine | Tofranil | Depression, bedwetting | Urine |
| Meperidine | Demerol | Moderate to severe pain | Urine |
| Ketamine | Ketalar | Anaesthesia, treatment-resistant depression | Urine |
| Lamotrigine | Lamictal | Epilepsy, bipolar disorder | Urine |
| Thioridazine | Mellaril | Schizophrenia | Urine |
Barbiturates
Barbiturate screens are generally reliable, but certain NSAIDs and sleep aids have been documented to cause non-negative results.
| Medication (Generic) | Common Brand Names | Commonly Used For | Test Type |
|---|---|---|---|
| Phenytoin | Dilantin | Epilepsy, seizure disorders | Urine |
| Primidone | Mysoline | Epilepsy | Urine |
| Ibuprofen | Advil, Motrin | Pain, fever, inflammation | Urine |
| Naproxen | Aleve, Naprosyn | Pain, inflammation | Urine |
| Doxylamine | Unisom SleepTabs | Sleep aid, morning sickness | Urine |
Cocaine (Benzoylecgonine)
The cocaine metabolite screen is highly specific. The primary documented cause of a non-negative result is coca leaf tea (herbal tea). Topical cocaine is used medically in ENT surgery and will produce a legitimate positive.
| Medication (Generic) | Common Brand Names | Commonly Used For | Test Type |
|---|---|---|---|
| Topical Cocaine HCl | Cocaine HCl solution (medical use) | ENT surgical and procedural anaesthesia | Urine Oral Fluid |
| Coca Leaf Tea | Mate de coca (herbal tea) | Herbal beverage (altitude sickness remedy) | Urine |
Methadone
Methadone immunoassays have documented cross-reactivity with several antipsychotics, antihistamines, and antidepressants.
| Medication (Generic) | Common Brand Names | Commonly Used For | Test Type |
|---|---|---|---|
| Diphenhydramine | Benadryl | Allergies, sleep aid | Urine |
| Doxylamine | Unisom SleepTabs | Sleep aid, morning sickness | Urine |
| Quetiapine | Seroquel | Schizophrenia, bipolar disorder | Urine |
| Chlorpromazine | Thorazine | Schizophrenia, bipolar disorder | Urine |
| Clomipramine | Anafranil | OCD, depression | Urine |
| Thioridazine | Mellaril | Schizophrenia | Urine |
| Verapamil | Calan, Isoptin | Heart conditions, hypertension | Urine |
LSD (Lysergic Acid Diethylamide)
LSD immunoassays are known to have broad cross-reactivity. A large number of antidepressants, antipsychotics, and other medications have been documented to produce non-negative LSD results.
| Medication (Generic) | Common Brand Names | Commonly Used For | Test Type |
|---|---|---|---|
| Amitriptyline | Elavil | Depression, neuropathic pain, migraine prevention | Urine |
| Desipramine | Norpramin | Depression | Urine |
| Doxepin | Sinequan, Silenor | Depression, insomnia, anxiety | Urine |
| Imipramine | Tofranil | Depression, bedwetting | Urine |
| Fluoxetine | Prozac | Depression, anxiety, OCD | Urine |
| Sertraline | Zoloft | Depression, anxiety, OCD, PTSD | Urine |
| Bupropion | Wellbutrin, Zyban | Depression, smoking cessation | Urine |
| Trazodone | Desyrel | Depression, insomnia | Urine |
| Venlafaxine | Effexor | Depression, anxiety | Urine |
| Buspirone | Buspar | Anxiety | Urine |
| Risperidone | Risperdal | Schizophrenia, bipolar disorder | Urine |
| Haloperidol | Haldol | Schizophrenia, Tourette's syndrome | Urine |
| Chlorpromazine | Thorazine | Schizophrenia, bipolar disorder | Urine |
| Prochlorperazine | Stemetil, Compazine | Nausea, vomiting, migraine | Urine |
| Thioridazine | Mellaril | Schizophrenia | Urine |
| Metoclopramide | Maxeran, Reglan | Nausea, gastroparesis | Urine |
| Diltiazem | Cardizem, Tiazac | Hypertension, angina, arrhythmia | Urine |
| Verapamil | Calan, Isoptin | Heart conditions, hypertension | Urine |
| Fentanyl | Duragesic, Actiq | Severe pain, anaesthesia | Urine |
| Methylphenidate | Ritalin, Concerta | ADHD | Urine |
| Labetalol | Trandate | Hypertension | Urine |
| Brompheniramine | Dimetapp | Allergies, cold symptoms | Urine |
Tricyclic Antidepressants (TCAs)
TCA immunoassay screens can produce non-negative results with certain antipsychotics and muscle relaxants that share structural similarities with tricyclic antidepressants.
| Medication (Generic) | Common Brand Names | Commonly Used For | Test Type |
|---|---|---|---|
| Cyclobenzaprine | Flexeril | Muscle spasms, musculoskeletal pain | Urine |
| Quetiapine | Seroquel | Schizophrenia, bipolar disorder, depression | Urine |
| Carbamazepine | Tegretol | Epilepsy, bipolar disorder, neuropathic pain | Urine |
| Cyproheptadine | Periactin | Allergies, appetite stimulation | Urine |
| Diphenhydramine | Benadryl | Allergies, sleep aid | Urine |
| Hydroxyzine | Atarax, Vistaril | Anxiety, allergies | Urine |
Buprenorphine
Buprenorphine immunoassay screens used to monitor opioid use disorder treatment have documented cross-reactivity with certain antipsychotics and analgesics.
| Medication (Generic) | Common Brand Names | Commonly Used For | Test Type |
|---|---|---|---|
| Amisulpride | Solian | Schizophrenia | Urine |
| Sulpiride | Dolmatil | Schizophrenia, depression | Urine |
| Tramadol | Ultram, Zytram | Moderate to severe pain | Urine |
Note on Oral Fluid Testing
Oral fluid (saliva) drug tests have a shorter detection window than urine tests and are generally less susceptible to cross-reactivity. However, medications marked with an oral fluid indicator above have been documented to cause non-negative results on oral fluid immunoassay screens. The same MRO review process applies to both test types.
Important Notice
This information is provided for educational purposes to help donors prepare for their drug test appointment. It is not a guarantee of any specific test result. The cross-reactivity of any medication depends on the specific immunoassay used, the dose taken, and individual metabolism. All non-negative results are subject to Medical Review Officer (MRO) review and confirmatory testing before any final determination is made. If you have questions about your medications and drug testing, consult your prescribing physician or pharmacist.
Taking one of these medications?
Upload your prescription label, physician letter, or pharmacy dispensing record securely for the Medical Review Officer.