Phenobarbital and Estradiol Interaction
Drug interaction information between Phenobarbital and Estradiol.
Phenobarbital and Estradiol have a documented minor interaction in FDA labeling.
FDA drug labeling documents a minor-severity interaction between Phenobarbital and Estradiol. This page displays the available source-record category and label text. The category is not an individual risk estimate or medication-combination direction.
How They Interact
Phenobarbital makes your body break down estradiol faster than normal, which makes the hormone medicine less effective.
FDA Label Information
Estradiol, Estrone Progesterone, and Other Steroidal Hormones Pretreatment with or concurrent administration of phenobarbital may decrease the effect of estradiol by increasing its metabolism.
Phenobarbital Also Interacts With
- Nirmatrelvir/Ritonavir major
- Ranolazine major
- Voriconazole major
- Canagliflozin moderate
- Cenobamate moderate
Estradiol Also Interacts With
- Drospirenone/Ethinyl Estradiol major
- Glecaprevir/Pibrentasvir moderate
- Etonogestrel moderate
- Tacrolimus Topical moderate
- Rosuvastatin minor
Frequently Asked Questions
What SPL severity band is on file for Phenobarbital + Estradiol?
Compiled FDA labeling labels this pair minor. That is a source-record field, not an individual medication-combination decision.
Which drug in this pair has the larger labeled-interaction portfolio?
Phenobarbital has 59 labeled pairs on file vs Estradiol's 54. In the minor band specifically: Phenobarbital has 43 (also Doxycycline, Progesterone, Griseofulvin, Bazedoxifene); Estradiol has 50 (also Rosuvastatin, Lamotrigine, Topiramate, Tizanidine).
What mechanism field is on file for Phenobarbital and Estradiol?
Phenobarbital makes your body break down estradiol faster than normal, which makes the hormone medicine less effective.
Phenobarbital carries more major-labeled pairs than Estradiol
SPL source-record counts only. This page's band is minor · classes on file: Phenobarbital (Anticonvulsant (Barbiturate)); Estradiol (Estrogen Hormone).
Phenobarbital has 3 major-labeled pairs vs Estradiol's 1. This page itself is in the minor band, not the major band.
3 major · 13 moderate · 43 minor · 59 total
- Other minor peers for Phenobarbital
- Doxycycline
- Progesterone
- Griseofulvin
- Bazedoxifene
1 major · 3 moderate · 50 minor · 54 total
- Other minor peers for Estradiol
- Rosuvastatin
- Lamotrigine
- Topiramate
- Tizanidine
Sources: FDA Drug Labels (SPL) via openFDA (2026). This is for informational purposes only and is not medical advice. This registry does not provide individual medication-combination directions.
Read our methodology - how this data is sourced, computed, and verified.