Can taking naproxen cause me to have a faulty urine screen?

the only way it shows up as a false positive is if u bought one of them over the counter home drug test cause they are never accurate. my wife works 4 quest diagnostic & that is one of the most asked questions so if ur test is done at a lab ur absolutely fine I actually take the naproxen cause the ibuprofrin 800's mess my stomach up. but ur fine bro trust me...

Hey Crazydrugs,

The following is a list of drugs/conditions that can cause a false positive for marijuana (THC) and cocaine:

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)

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

As you can see the naproxen is listed for causing a false positive for THC, but not sure why you had a positive for cocaine.

I found this by googling false positive on drug test if you want to do some more reading.

Best wishes,

Laurie