Lorazepam and Probenecid Interaction
Drug interaction information between Lorazepam and Probenecid.
Lorazepam and Probenecid have a documented minor interaction in FDA labeling.
FDA drug labeling documents a minor-severity interaction between Lorazepam and Probenecid. 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
Probenecid blocks the liver from processing lorazepam, which makes the drug stay in your system longer and work more strongly.
FDA Label Information
Concurrent administration of lorazepam with probenecid may result in a more rapid onset or prolonged effect of lorazepam due to increased half-life and decreased total clearance. Lorazepam dosage needs to be reduced by approximately 50% when coadministered with probenecid. The effects of probenecid and valproate on lorazepam may be due to inhibition of glucuronidation.
Lorazepam Also Interacts With
- Valproate minor
- Clozapine minor
- Theophylline minor
- Aripiprazole minor
- Clarithromycin minor
Probenecid Also Interacts With
- Ketorolac major
- Levofloxacin major
- Amoxicillin moderate
- Amoxicillin/Clavulanate moderate
- Ceftazidime/Avibactam moderate
Frequently Asked Questions
What SPL severity band is on file for Lorazepam + Probenecid?
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?
Probenecid has 37 labeled pairs on file vs Lorazepam's 11. In the minor band specifically: Lorazepam has 11 (also Valproate, Clozapine, Theophylline, Aripiprazole); Probenecid has 23 (also Theophylline, Acetaminophen/Oxycodone, Ampicillin/Sulbactam, Carbidopa/Levodopa).
What mechanism field is on file for Lorazepam and Probenecid?
Probenecid blocks the liver from processing lorazepam, which makes the drug stay in your system longer and work more strongly.
Probenecid carries more major-labeled pairs than Lorazepam
SPL source-record counts only. This page's band is minor · classes on file: Lorazepam (Benzodiazepine); Probenecid (Uricosuric Agent).
Probenecid has 2 major-labeled pairs vs Lorazepam's 0. This page itself is in the minor band, not the major band.
0 major · 0 moderate · 11 minor · 11 total
- Other minor peers for Lorazepam
- Valproate
- Clozapine
- Theophylline
- Aripiprazole
2 major · 12 moderate · 23 minor · 37 total
- Other minor peers for Probenecid
- Theophylline
- Acetaminophen/Oxycodone
- Ampicillin/Sulbactam
- Carbidopa/Levodopa
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.