What the FDA labels say about taking them together
Efavirenz and guanfacine
Guanfacine's FDA label of June 23, 2025 names efavirenz in its drug interactions section; the efavirenz label PlainMeds reads does not name guanfacine. The guanfacine label: “Consider dose increase”
Check it at the source: the efavirenz FDA label on DailyMed (effective March 31, 2024, Cipla USA Inc.); the guanfacine FDA label on DailyMed (effective June 23, 2025, Takeda Pharmaceuticals America, Inc.).
What does the efavirenz label say about guanfacine?
Efavirenz's label (effective March 31, 2024) 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 (Efavirenz), Cipla USA Inc., effective March 31, 2024 (SPL set 92603fa5-7a2c-4bfb-9a70-aadb4fba952c), via openFDA; the full label on DailyMed
What does the guanfacine label say about efavirenz?
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
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
| Efavirenz | Guanfacine | |
|---|---|---|
| Labeled for | HIV | ADHD, High blood pressure |
| Boxed warning | No | No |
| Pharmacy cost (NADAC) | $1.28 per tablet 600 mg tablet | $0.147 per tablet 1 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