What the FDA labels say about taking them together
Guanfacine and rifampin
Guanfacine's FDA label of June 23, 2025 names rifampin in its drug interactions section; the rifampin label PlainMeds reads does not name guanfacine. The guanfacine label: “Consider dose increase”
Check it at the source: the guanfacine FDA label on DailyMed (effective June 23, 2025, Takeda Pharmaceuticals America, Inc.); the rifampin FDA label on DailyMed (effective February 11, 2026, Lupin Pharmaceuticals, Inc.).
What does the guanfacine label say about rifampin?
Guanfacine label, drug interactionsConcomitant Drug Name or Drug Class: Strong and moderate CYP3A4 inducers, e.g., rifampin, efavirenz; Clinical Rationale and Magnitude of Drug Interaction: Guanfacine is primarily metabolized by CYP3A4 and its plasma concentrations can be significantly affected resulting in a decrease in exposure; Clinical Recommendation: Consider dose increase [see ]
Source: FDA drug label (Intuniv), Takeda Pharmaceuticals America, Inc., effective June 23, 2025 (SPL set b972af81-3a37-40be-9fe1-3ddf59852528), via openFDA; the full label on DailyMed
What does the rifampin label say about guanfacine?
Rifampin's label (effective February 11, 2026) does not name guanfacine in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (rifampin), Lupin Pharmaceuticals, Inc., effective February 11, 2026 (SPL set b56004f0-f23d-47f6-80c7-39884fccbccc), 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
| Guanfacine | Rifampin | |
|---|---|---|
| Labeled for | ADHD, High blood pressure | n/a |
| Boxed warning | No | No |
| Pharmacy cost (NADAC) | $0.147 per tablet 1 mg tablet | $0.679 per capsule 300 mg capsule |
| Shortage now | A presentation being discontinued | In shortage |
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