What the FDA labels say about taking them together
Amphetamine and ascorbic acid
Amphetamine's FDA label of August 20, 2026 names ascorbic acid in its drug interactions section, and ascorbic acid's label names amphetamine too. The ascorbic acid label: “Bleomycin is inactivated in vitro by ascorbic acid. Amphetamine and Other Drugs Affected by Urine Acidification: Ascorbic acid may cause acidification of the urine and result in decreased amphetamine serum levels …”
Check it at the source: the amphetamine FDA label on DailyMed (effective August 20, 2026, Aurolife Pharma, LLC); the ascorbic acid FDA label on DailyMed (effective May 29, 2026, McGuff Pharmaceuticals, Inc.).
What does the amphetamine label say about ascorbic acid?
Amphetamine label, drug interactionsAcidifying agents Gastrointestinal acidifying agents (guanethidine, reserpine, glutamic acid HCl, ascorbic acid, fruit juices, etc.) lower absorption of amphetamines.
Source: FDA drug label (Amphetamine Sulfate), Aurolife Pharma, LLC, effective August 20, 2026 (SPL set 20735c2e-6304-425f-a4e4-584f6f90d6a0), via openFDA; the full label on DailyMed
What does the ascorbic acid label say about amphetamine?
Ascorbic acid label, drug interactionsBleomycin is inactivated in vitro by ascorbic acid (7.1). Amphetamine and Other Drugs Affected by Urine Acidification: Ascorbic acid may cause acidification of the urine and result in decreased amphetamine serum levels affect excretion and plasma concentrations of other drugs sensitive to urine pH (7.2). Warfarin: Continue standard monitoring (7.3) See 17 for PATIENT COUNSELING INFORMATION Antibiotics: Ascorbic acid may decrease the activities of erythromycin, kanamycin, streptomycin, doxycycline, and lincomycin.
Source: FDA drug label (Ascor), McGuff Pharmaceuticals, Inc., effective May 29, 2026 (SPL set 388aad52-fc01-4784-9791-1dbc80c69306), via openFDA; the full label on DailyMed
These are the labels' own sentences. PlainMeds does not grade interactions; a pharmacist or prescriber can say what they mean for one person's medicines.
Both medicines on the record
| Amphetamine | Ascorbic acid | |
|---|---|---|
| Labeled for | ADHD | n/a |
| Boxed warning | Yes | No |
| Pharmacy cost (NADAC) | $0.449 per tablet 10 mg tablet | n/a |
| Shortage now | No current entry | No current entry |
Source: FDA NDC Directory, CMS NADAC of October 7, 2026 and the FDA Drug Shortage Database (FDA files October 8, 2026)
What next?
- Check more medicines together
- up to five at once