Urinary and stomach pH levels can have a strong effect on DL-amphetamine excretion and absorption.[28] An acidic stomach and GI pH will decrease the absorption of Adderall,[12] and acidic urine levels will decrease the reabsorption of the drug through the renal system.[29] Co-administration of acidic substances (e.g., citric acid) causes decreased renal reabsorption of DL-amphetamine; whereas, alkaline agents (e.g., antacids) may cause a marked increase in renal tubular reabsorption. The increased reabsorption can increase the retention of amphetamines, with potential to result in dangerously high serum levels
Fuck yeah, antacids.