Metronidazole and Cimetidine Interaction
Drug interaction information between Metronidazole and Cimetidine.
Metronidazole and Cimetidine have a documented minor interaction in FDA labeling.
FDA drug labeling documents a minor-severity interaction between Metronidazole 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 slows down how fast your liver breaks down metronidazole, which causes the medicine to stay in your body longer.
FDA Label Information
Drugs that Inhibit CYP450 Enzymes The simultaneous administration of drugs that decrease microsomal liver enzyme activity, such as cimetidine, may prolong the half-life and decrease plasma clearance of metronidazole.
Metronidazole Also Interacts With
- Theophylline major
- Lithium minor
- Disulfiram minor
- Phenytoin minor
- Phenobarbital minor
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 Metronidazole + 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 Metronidazole's 10. In the minor band specifically: Metronidazole has 9 (also Lithium, Disulfiram, Phenytoin, Phenobarbital); Cimetidine has 63 (also Albendazole, Alogliptin, Alosetron, Alprazolam).
What mechanism field is on file for Metronidazole and Cimetidine?
Cimetidine slows down how fast your liver breaks down metronidazole, which causes the medicine to stay in your body longer.
Cimetidine carries more major-labeled pairs than Metronidazole
SPL source-record counts only. This page's band is minor · classes on file: Metronidazole (Nitroimidazole Antibiotic); Cimetidine (H2 Receptor Antagonist).
Cimetidine has 4 major-labeled pairs vs Metronidazole's 1. This page itself is in the minor band, not the major band.
1 major · 0 moderate · 9 minor · 10 total
- Other minor peers for Metronidazole
- Lithium
- Disulfiram
- Phenytoin
- Phenobarbital
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.