Is it normal to have a drug test threshold 1000 ng/mL for 5 mg of Dextro-amphetamine?

Question

Hi doctor,

I take 5 mg of Dextro-amphetamine (low-dose Adderall) daily as prescribed. I have to take a monthly drug test. However, my results consistently show negative for Amphetamines which is a problem because they see I have a prescription for Dextro-amphetamine. Yet, it appears I am doing something else with it since my urinalysis keeps showing negative for Amphetamines. I do not know why my results keep coming back negative. I know I am taking a very low dose, though, and the drug test threshold is 1000 ng/mL. I am currently taking Methadone (55 mg), Wellbutrin (300 mg), and Propanolol (40 mg). Is that too high of a threshold for 5 mg of Dextro-amphetamine?

Answer 1

Hi,

Welcome to icliniq.com. I understand your concern. Amphetamine excretion increases with increasing urine flow. Therefore, high urine flow (due to over-drinking water or diuretic drugs) will increase excretion. Hence not detectable in urine. The excretion is also increased with acidic urine pH. If any acidic foods (lemon, orange, vitamin C, etc.) or acidic drugs can hurry up the excretion of Amphetamine, so not be detected in urine. Please think about any such foods you are consuming. The concomitant drugs do not have any of such actions. The earlier research on human volunteers showed that the urine Amphetamine test was positive only in 19 % if the oral dose was 5 mg. As the dose is increased, the detecting ability is increased. Another factor is the screening cutoff of 1000 ng/mL (reference range), which is too high for the low (5 mg) oral dose. The above-said factors contribute to your urine negative test. I hope you find it helpful. Kind regards.