What the FDA labels say about taking them together
Gabapentin and magnesium hydroxide
Gabapentin's FDA label of May 12, 2026 names magnesium hydroxide in its drug interactions section; the magnesium hydroxide label PlainMeds reads does not name gabapentin. The gabapentin label: “Maalox ® The mean bioavailability of gabapentin was reduced by about 20% with concomitant use of an antacid (Maalox ® ) containing magnesium and aluminum hydroxides.”
Check it at the source: the gabapentin FDA label on DailyMed (effective May 12, 2026, Viatris Specialty LLC); the magnesium hydroxide FDA label on DailyMed (effective August 21, 2026).
What does the gabapentin label say about magnesium hydroxide?
Gabapentin label, drug interactionsMaalox ® (aluminum hydroxide, magnesium hydroxide) The mean bioavailability of gabapentin was reduced by about 20% with concomitant use of an antacid (Maalox ® ) containing magnesium and aluminum hydroxides.
Gralise label (Almatica Pharma LLC, June 30, 2026), drug interactionsAn increase in gabapentin AUC values have been reported when administered with hydrocodone. ( 7.6 ) An increase in gabapentin AUC values have been reported when administered with morphine. ( 7.7 ) An antacid containing aluminum hydroxide and magnesium hydroxide reduced the bioavailability of gabapentin immediate release by about approximately 20%, but by only 5% when gabapentin was taken 2 hours after antacids.
Source: FDA drug label (Gralise, NDA022544), Almatica Pharma LLC, effective June 30, 2026 (SPL set 466273b1-c9fc-3930-c94b-aa11394d5140), via openFDA
Source: FDA drug label (Neurontin), Viatris Specialty LLC, effective May 12, 2026 (SPL set 97935fd9-1d4a-43b6-a5d9-de994591187b), via openFDA; the full label on DailyMed
What does the magnesium hydroxide label say about gabapentin?
Magnesium hydroxide's label (effective August 21, 2026) does not name gabapentin in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (MiraFAST soft chews), Bayer HealthCare LLC., effective August 21, 2026 (SPL set 2cee67dd-b71f-32b8-e063-6394a90ae864), 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
| Gabapentin | Magnesium hydroxide | |
|---|---|---|
| Labeled for | Nerve pain and fibromyalgia, Seizures and epilepsy | Constipation, Acid reflux and ulcers |
| Boxed warning | No | No |
| Pharmacy cost (NADAC) | $0.0218 per capsule 100 mg capsule | $0.0095 per mL Milk of magnesia suspension |
| 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