It has been proven that amoxicillin along with many new types of anti=biotics can cause false positives on a drug test. Best to talk to your pharmacist AND doctor to prior to a drug test to know what...
Not that I'm aware of, but colchicine can kill you.
i think not
not for cocaine, possibly for opiates considering it metabolizes into morphine...
In VERY high doses it can rarely show a false positive, but that kind of dosage would be very unsafe.