Georgia DUI Blog

Substances that cause False Positive Drug Test Results

THC - Substances or Conditions which can cause false positives
Dronabinol (Marinol)
Ibuprofen; (Advil, Nuprin, Motrin, Excedrin IB etc)
Ketoprofen (Orudis KT)
Kidney infection (Kidney disease, diabetes) Liver Disease
Naproxen (Aleve)
Promethazine (Phenergan, Promethegan)
Riboflavin (B2, Hempseed Oil)

Amphetamines - Substances or Conditions which can cause false positives
Ephedrine, pseudoephedrine, propylephedrine, phenylephrine, or desoxyephedrine
(Nyquil, Contact, Sudafed, Allerest, Tavist-D, Dimetapp, etc)
Phenegan-D, Robitussin Cold and Flu, Vicks Nyquil
Over-the-counter diet aids with phenylpropanolamine (Dexatrim, Accutrim)
Over-the-counter nasal sprays (Vicks inhaler, Afrin)
Asthma medications (Marax, Bronkaid tablets, Primatine Tablets)
Prescription medications (Amfepramone, Cathne, Etafediabe, Morazone,phendimetrazine, phenmetrazine, benzphetamine, fenfluramine, dexfenfluramine,dexdenfluramine,Redux, mephentermine, Mesocarb, methoxyphenamine, phentermine,amineptine, Pholedrine, hydroymethamphetamine, Dexedrine, amifepramone, clobenzorex,fenproyorex, mefenorex, fenelylline, Didrex, dextroamphetamine, methphenidate, Ritalin,pemoline, Cylert, selegiline, Deprenyl, Eldepryl, Famprofazone) Kidney infection, kidney disease, Liver disease, diabetes

Opiates - Substances or Conditions which can cause false positives
Poppy Seeds
Tylenol with codeine
Most prescription pain medications
Cough suppressants with Dextromethorphan (DXM)
Nyquil
Kidney infection, Kidney Disease
Diabetes, Liver Disease

Ecstacy - Substances or Conditions which can cause false positives
Ephedrine, pseudoephedrine, propylephedrine, phenylephrine, or desoxyephedrine
(Nyquil, Contact, Sudafed, Allerest, Tavist-D, Dimetapp, etc)
Phenegan-D, Robitussin Cold and Flu, Vicks Nyquil
Over-the-counter diet aids with phenylpropanolamine (Dexatrim, Accutrim)
Over-the-counter nasal sprays (Vicks inhaler, Afrin)
Asthma medications (Marax, Bronkaid tablets, Primatine Tablets)
Prescription medications (Amfepramone, Cathne, Etafediabe, Morazone,phendimetrazine, phenmetrazine, benzphetamine, fenfluramine, dexfenfluramine, dexdenfluramine,Redux, mephentermine, Mesocarb, methoxyphenamine, phentermine, amineptine, Pholedrine, hydroymethamphetamine, Dexedrine, amifepramone, clobenzorex, fenproyorex, mefenorex, fenelylline, Didrex, dextroamphetamine, methphenidate, Ritalin, pemoline, Cylert, selegiline, Deprenyl, Eldepryl, Famprofazone) Kidney infection, kidney disease
Liver disease, diabetes

Cocaine - Substances or Conditions which can cause false positives
Kidney infection (kidney disease)
Liver infection (liver disease)
Amoxicillin, tonic water

     If a person has taken methamphetamine, that individual should also have its metabolite amphetamine in their system. In other words, levels of both methamphetamine and amphetamine should be detected in both the blood and urine. Some GC/MS assays can falsely yield positive methamphetamine levels when high concentrations of ephedrine or pseudoephedrine are present in the specimen. Depending on the temperature of the injection port, the ephedrine or pseudoephedrine can be converted (or cooked) to methamphetamine. Therefore, sound scientific practice requires a negative report for methamphetamine if only methamphetamine is found in blood or urine. The absence of amphetamine means that the person had not consumed methamphetamine, which would in the ordinary course of metabolism would produce amphetamine. Therefore, in a case where only methamphetamine is found in the blood or urine the person probably had a cold and taken cold medicine containing ephedrine or pseudoephedrine.