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diflunisal

Salicylate derivative · Analgesic, Anti-inflammatory

Salicylate derivativeAnalgesic, Anti-inflammatory
CDSCO approved
EXCRETION
—
not curated
INTERACTIONS
12 major
SEVERE in our sources
PREGNANCY
C
FDA category + note
Top interactionssee all 12 →
  • AcalabrutinibSevereDatabaseDDInter
  • AnisindioneSevereDatabaseDDInter
  • ApixabanSevereDatabaseDDInter
  • ArdeparinSevereDatabaseDDInter

Mechanism

Diflunisal is a competitive inhibitor of cyclooxygenase (COX). It is not metabolized to salicylic acid.

Indications

Analgesia (osteoarthritis, musculoskeletal strains or sprains)Mild to moderate painOsteoarthritisRheumatoid arthritis

Dosing

Adult
250–500 mg every 8–12 h (maximum = 1 g/dose and 4 g/day)
Pediatric
Children <12 y: 10–15 mg/kg every 4 h (maximum 5 doses/24 h)

Pharmacokinetics

Onset
Peak plasma concentration (Cp) 2–3 h
Half-life
8–12 h
Protein binding
99%
Metabolism
Glucuronide metabolite

Side effects

Common
Fewer auditory side effects than aspirinFewer and less intense GI side effects than aspirinFewer antiplatelet effects than aspirin

Pregnancy & lactation

Pregnancy

C

Lactation

Excreted into breast milk.

Drug interactions

Acalabrutinib
Severe
Database

Drug interaction classified as: synergy

Source: DDInter

Anisindione
Severe
Database

Drug interaction classified as: synergy

Source: DDInter

Apixaban
Severe
Database

Drug interaction classified as: synergy

Source: DDInter

Ardeparin
Severe
Database

Drug interaction classified as: synergy

Source: DDInter

Avapritinib
Severe
Database

Drug interaction classified as: synergy

Source: DDInter

Betrixaban
Severe
Database

Drug interaction classified as: synergy

Source: DDInter

Brinzolamide
Severe
Database

Drug interaction classified as: distribution

Source: DDInter

Cabozantinib
Severe
Database

Drug interaction classified as: synergy

Source: DDInter

Cidofovir
Severe
Database

Drug interaction classified as: synergy

Source: DDInter

Dalteparin
Severe
Database

Clinical effect not specified

Source: DDInter

Danaparoid
Severe
Database

Clinical effect not specified

Source: DDInter

Dasatinib
Severe
Database

Clinical effect not specified

Source: DDInter

Related guidelines

Rheumatoid arthritis
IRA · Rheumatology · 2023
Rheumatoid arthritis
EULAR · Rheumatology · 2022
Rheumatoid arthritis
ACR · Rheumatology · 2021
Knee osteoarthritis
MOHFW · Orthopaedics · 2021
Inflammatory bowel disease
OTHER · Gastroenterology · 2015

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Textbook-sourced·Sources: Goodman & Gilman 14e·Updated: 2026-05-10