How long will Zantac show up in a urine test?

28 Dec 2009

I am sorry I do not know the answer. But this is a great question as I did not know Zantac will cause a false positive for methamphetamine and amphetamine.

Thank you for asking this and I look forward for an answer

3 Feb 2013

Zantac (ranitidine) is well documented as providing a false positive result for amphetamines in urine drug screens.
If you have taken Zantac legitimately (on a doctors prescription) tell the drug testing personnel.

The half-life of Zantac is about 3 hours. This is the time it takes for the drug level in your plasma to be reduced by half. So half of the Zantac is out of your system in 3 hours, leaving half. Half of the remaining half is out in the next 3 hours leaving 1/4. Half of the remaining 1/4 is out in the next 3 hours leaving 1/8, etc.
As a rough estimate it usually takes around 5.5 half lives for a drug to be eliminated from your system. So 5.5 x 3 = 16.5 hours.
To be safe allow 24 hours for Zantac to be out of your system.