Diclofenac

General

• Type: NSAID
• Dosage Forms: Capsule 18mg, 25mg, 35mg; ER Tablet 100mg
• Common Trade Names: Zorvolex

Adult Dosing

Pain, mild-moderate

• Tablet PO 50mg TID, may administer 100mg as first dose

Ankylosing Spondylitis

• PO Delayed Release 25mg 4x daily and 25mg qhs prn

Osteoarthritis

• 35mg PO TID

Pediatric Dosing

NA

Special Populations

• Pregnancy Rating: C, category D if >30wks after gestation
• Lactation: probably safe
• Renal dosing: monitor renal function closely if advanced renal disease
• Hepatic dosing: max 54mg/day

Contraindications

• allergy to class/drug
• ASA or NSAID-induced asthma or urticaria
• caution if:
  • renal impairment, dehydration, elderly or debilitated
  • history of GI bleed or ulcers, alcohol use, or coagulopathy
  • hepatic impairment
  • asthma
  • cardiovascular disease (or high risk of), including CABG surgery periop use, recent MI, CHF, HTN, smoker
  • fluid retention
  • PKU
  • prolonged use

Adverse Reactions

Serious

• GI bleed, ulcer, perforation
• blood dyscrasias, prolonged bleeding time, anemia
• nephrotoxicity, renal papillary necrosis
• MI, stroke, thromboembolism, HTN, CHF
• hepatotoxicity, hepatic necrosis, pancreatitis
• bronchospasm
• exfoliative dermatitis, SJS/TEN

Common

• dyspepsia, nausea/vomiting, abdominal pain, diarrhea, constipation, flatulence
• headache, dizziness, drowsiness, tinnitus
• dizziness
• rash, pruritus, urticaria, photosensitivity
• fluid retention, peripheral edema
• ecchymosis
• elevated creatinine, ALT/AST
• sinusitis

Pharmacology

• Half-life: 1.9 hours
• Metabolism: liver; CYP450 (2C8, 2C9, 3A4 substrate), UGT (2B7 substrate)
• Excretion: urine 65%, bile 35%
• Mechanism of Action: exact MOA unknown; inhibits cyclooxyrgenase, reducing prostaglandin and thromboxane synthesis

See Also

• NSAID
• NSAID toxicity