Guanfacine has 13 known drug interactions based on U.S. FDA drug labeling data. 8 are classified as major interactions requiring close medical supervision. Notable interactions include combinations with Efavirenz, Esmolol Hydrochloride, Fluconazole. Patients taking Guanfacine should inform their healthcare provider of all current medications — including over-the-counter drugs and supplements — to avoid potentially harmful combinations. Data sourced from OpenFDA and the NIH National Library of Medicine.
- Total
- 13
- Major
- 8
- Moderate
- 3
- Minor
- 2
Major (8)
- Guanfacine + Efavirenz— CYP3A4 inducer that significantly decreases guanfacine plasma concentrations and exposure. Guanfacine dose increase up t…
- Guanfacine + Esmolol Hydrochloride— Beta blockers increase risk of guanfacine-withdrawal rebound hypertension. If antihypertensive therapy must be interrupt…
- Guanfacine + Fluconazole— CYP3A4 inhibitor that significantly increases guanfacine plasma concentrations and exposure. Dose reduction to 50% of ta…
- Guanfacine + Ketoconazole— CYP3A4 inhibitor that significantly increases guanfacine plasma concentrations and exposure. Dose reduction to 50% of ta…
- Guanfacine + Phenylephrine Hci— Centrally-acting sympatholytic agent that increases the pressor effect of phenylephrine hydrochloride.
- Guanfacine + Phenylephrine Hydrochloride— Centrally-acting sympatholytic agent that increases the pressor effect of phenylephrine hydrochloride.
- Guanfacine + Phenylephrine Hydrochloride Injection, Solution— Centrally-acting sympatholytic agent increases pressor effect of phenylephrine hydrochloride.
- Guanfacine + Rifampin— CYP3A4 inducer that significantly decreases guanfacine plasma concentrations and exposure. Guanfacine dose increase up t…
Moderate (3)
- Guanfacine + Cns-Depressant Drugs— Potential for increased sedation when guanfacine is given concomitantly with CNS-depressant drugs.
- Guanfacine + Phenobarbital— Microsomal enzyme inducer that reduces guanfacine elimination half-life and plasma concentration, particularly in patien…
- Guanfacine + Phenytoin— Microsomal enzyme inducer that reduces guanfacine elimination half-life and plasma concentration, particularly in patien…
Minor (2)
- Guanfacine + Diuretics— No drug interactions reported when guanfacine administered together with diuretics in well-controlled studies.
- Guanfacine + Oral Anticoagulants— No changes in degree of anticoagulation observed when guanfacine administered with oral anticoagulants at 1-2 mg/day for…