Doxepin and Cimetidine Interaction
Drug interaction information between Doxepin and Cimetidine.
Doxepin and Cimetidine have a documented minor interaction in FDA labeling.
FDA drug labeling documents a minor-severity interaction between Doxepin and Cimetidine. 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
Cimetidine blocks the enzymes that normally break down doxepin, which causes the amount of doxepin in your body to double.
FDA Label Information
( 4.2 ) Cimetidine: Increases exposure to doxepin. 7.2 Cimetidine Doxepin exposure is doubled with concomitant administration of cimetidine, a nonspecific inhibitor of CYP isozymes. A maximum dose of 3 mg is recommended in adults and elderly when cimetidine is co-administered with doxepin [see Clinical Pharmacology (12.3 )] 7.3 Alcohol When taken with doxepin, the sedative effects of alcohol may be potentiated [ see Warnings and Precautions (5.2 , 5.4 )].
Cimetidine Also Interacts With
- Levofloxacin major
- Posaconazole major
- Risperidone major
- Valproate major
- Empagliflozin moderate
Frequently Asked Questions
What SPL severity band is on file for Doxepin + Cimetidine?
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?
Cimetidine has 77 labeled pairs on file vs Doxepin's 3. In the minor band specifically: Doxepin has 3 (also Dopamine, Ramelteon); Cimetidine has 63 (also Albendazole, Alogliptin, Alosetron, Alprazolam).
What mechanism field is on file for Doxepin and Cimetidine?
Cimetidine blocks the enzymes that normally break down doxepin, which causes the amount of doxepin in your body to double.
Cimetidine carries more major-labeled pairs than Doxepin
SPL source-record counts only. This page's band is minor · classes on file: Doxepin (Tricyclic Antidepressant (TCA)); Cimetidine (H2 Receptor Antagonist).
Cimetidine has 4 major-labeled pairs vs Doxepin's 0. This page itself is in the minor band, not the major band.
4 major · 10 moderate · 63 minor · 77 total
- Other minor peers for Cimetidine
- Albendazole
- Alogliptin
- Alosetron
- Alprazolam
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.