Phentermine has 3 known drug interactions based on U.S. FDA drug labeling data. Of these, 1 are contraindicated combinations that should be avoided entirely. Notable interactions include combinations with Venlafaxine Hydrochloride, Ioflupane I-123, Venlafaxine Hcl Er. Patients taking Phentermine 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
- 3
- Contraindicated
- 1
- Moderate
- 2
Contraindicated (1)
- Phentermine + Venlafaxine Hydrochloride— Safety and efficacy in combination not established. Coadministration not recommended.
Moderate (2)
- Phentermine + Ioflupane I-123— Binds to dopamine transporter with high affinity and may interfere with Ioflupane I-123 imaging results.
- Phentermine + Venlafaxine Hcl Er— Safety and efficacy of coadministration not established; concurrent use not recommended.