What the FDA labels say about taking them together
Canagliflozin and phenobarbital
Canagliflozin's FDA label of June 11, 2026 names phenobarbital in its drug interactions section; the phenobarbital labels PlainMeds reads (2) do not name canagliflozin. The canagliflozin label: “UGT enzyme inducers decrease canagliflozin exposure which may reduce the effectiveness of INVOKANA.”
Check it at the source: the canagliflozin FDA label on DailyMed (effective June 11, 2026, Janssen Pharmaceuticals, Inc.); the phenobarbital FDA label on DailyMed (effective August 27, 2026).
What does the canagliflozin label say about phenobarbital?
Canagliflozin label, drug interactionsUGT Enzyme Inducers Clinical Impact: UGT enzyme inducers decrease canagliflozin exposure which may reduce the effectiveness of INVOKANA. … antihyperglycemic agent in patients who require additional glycemic control [see and ]. Examples: Rifampin, phenytoin, phenobarbital, ritonavir
Source: FDA drug label (INVOKANA), Janssen Pharmaceuticals, Inc., effective June 11, 2026 (SPL set b9057d3b-b104-4f09-8a61-c61ef9d4a3f3), via openFDA; the full label on DailyMed
What does the phenobarbital label say about canagliflozin?
Phenobarbital's label (effective August 27, 2026) and its 1 other brand-application label do not name canagliflozin in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (Phenobarbital), Chartwell RX, LLC, effective August 27, 2026 (SPL set 74428144-fb24-40a5-a670-3b876e2d116c), 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
| Canagliflozin | Phenobarbital | |
|---|---|---|
| Labeled for | Heart attack and coronary artery disease, Type 2 diabetes, Chronic kidney disease | Seizures and epilepsy |
| Boxed warning | No | No |
| Pharmacy cost (NADAC) | $19.13 per tablet 100 mg tablet | $0.213 per tablet 100 mg tablet |
| Shortage now | No current entry | A presentation being discontinued |
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