What the FDA labels say about taking them together
Cobicistat and magnesium hydroxide
Cobicistat's FDA label of February 10, 2026 names magnesium hydroxide in its drug interactions section; the magnesium hydroxide label PlainMeds reads does not name cobicistat.
Check it at the source: the cobicistat FDA label on DailyMed (effective February 10, 2026, Gilead Sciences, Inc.); the magnesium hydroxide FDA label on DailyMed (effective August 21, 2026).
What does the cobicistat label say about magnesium hydroxide?
Cobicistat label, drug interactionsConcomitant Drug Class/Drug Name: Antacids: e.g., aluminum and magnesium hydroxide (please also see and below); Potential Effect ↑ = Increase, ↓ = Decrease, ↔ = No change: ↓ atazanavir; Clinical Comment: TYBOST coadministered with atazanavir: With concomitant use, administer a minimum of 2 hours apart.
Source: FDA drug label (Tybost), Gilead Sciences, Inc., effective February 10, 2026 (SPL set 3784c35c-e87f-410c-900b-8fd6313c6010), via openFDA; the full label on DailyMed
What does the magnesium hydroxide label say about cobicistat?
Magnesium hydroxide's label (effective August 21, 2026) does not name cobicistat 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
| Cobicistat | Magnesium hydroxide | |
|---|---|---|
| Labeled for | HIV | Constipation, Acid reflux and ulcers |
| Boxed warning | No | No |
| Pharmacy cost (NADAC) | n/a | $0.0095 per mL Milk of magnesia suspension |
| Shortage now | A presentation being discontinued | 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