VOLTAREN
Clinical safety rating: caution
Comprehensive clinical and safety monograph for VOLTAREN (VOLTAREN).
Diclofenac inhibits cyclooxygenase (COX-1 and COX-2) enzymes, reducing prostaglandin synthesis, thereby providing anti-inflammatory, analgesic, and antipyretic effects.
| Metabolism | Diclofenac is primarily metabolized in the liver via cytochrome P450 2C9 (CYP2C9) and also by CYP3A4, followed by glucuronidation and sulfate conjugation. Minor metabolites include 4'-hydroxydiclofenac and 5-hydroxydiclofenac. |
| Excretion | Approximately 65% of a dose is excreted renally as unchanged drug and glucuronide conjugates, with about 35% eliminated via biliary/fecal routes as metabolites. |
| Half-life | Terminal elimination half-life is approximately 2 hours (range 1.2–2.5 hours) for diclofenac; this short half-life supports multiple daily dosing. The half-life is not significantly altered in renal impairment but may be prolonged in hepatic disease. |
| Protein binding | >99% bound primarily to albumin. |
| Volume of Distribution | 0.1–0.2 L/kg, indicating limited extravascular distribution consistent with high protein binding. |
| Bioavailability | Oral (immediate-release): ~50% (first-pass metabolism reduces bioavailability); Oral (enteric-coated): ~50%; Intramuscular: ~100%; Topical: approximately 6–10% systemically absorbed; Ophthalmic: negligible systemic absorption. |
| Onset of Action | Oral (immediate-release): 30 minutes; Oral (enteric-coated): 1-2 hours; Intramuscular: 15-30 minutes; Topical: 1-2 hours for local effect; Ophthalmic: 30 minutes. |
| Duration of Action | Oral (immediate-release): 4-6 hours; Oral (enteric-coated): up to 8 hours; Intramuscular: 4-6 hours; Topical: up to 12 hours for local relief; Ophthalmic: 4-6 hours for ocular inflammation. |
| Action Class | NSAID's- Non-Selective COX 1&2 Inhibitors (acetic acid) |
| Brand Substitutes | Dan 100mg Tablet SR, Defenac 100mg Tablet SR, Biovon 100mg Tablet SR, Dersy-SR 100 Tablet, Dolentia 100mg Tablet SR |
Oral: 50-100 mg every 8-12 hours; maximum 150 mg/day. IM: 75 mg once daily for up to 2 days. Topical gel: apply 2-4 g to affected area 4 times daily.
| Dosage form | SOLUTION/DROPS |
| Renal impairment | GFR <30 mL/min: contraindicated. GFR 30-60 mL/min: reduce dose, maximum 50 mg twice daily, monitor renal function. |
| Liver impairment | Child-Pugh A: no adjustment. Child-Pugh B: reduce dose by 50%; maximum 75 mg/day. Child-Pugh C: avoid use. |
| Pediatric use | Children ≥1 year: oral 0.5-1 mg/kg every 8-12 hours; maximum 3 mg/kg/day (up to 150 mg/day). Not recommended for <1 year. |
| Geriatric use | Start at lowest dose (e.g., 50 mg twice daily). Use minimum effective duration, maximum 100 mg/day. Monitor renal function, GI bleeding, and cardiovascular risk. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for VOLTAREN (VOLTAREN).
| Breastfeeding | Diclofenac is excreted into breast milk in low amounts; M/P ratio approximately 0.03. Considered compatible with breastfeeding due to low infant exposure. However, use with caution in lactating women with bleeding disorders or in infants with thrombocytopenia. |
| Teratogenic Risk | Nonsteroidal anti-inflammatory drug (NSAID) associated with increased risk of miscarriage and congenital malformations (particularly cardiac) if used in first trimester. Avoid use in third trimester due to risk of premature closure of ductus arteriosus, oligohydramnios, and necrotizing enterocolitis. FDA Pregnancy Category C (first and second trimesters), Category D (third trimester). |
■ FDA Black Box Warning
Nonsteroidal anti-inflammatory drugs (NSAIDs) cause an increased risk of serious cardiovascular thrombotic events, including myocardial infarction and stroke, which can be fatal. This risk may increase with duration of use. Patients with cardiovascular disease or risk factors for cardiovascular disease may be at greater risk. Diclofenac is contraindicated for the treatment of perioperative pain in the setting of coronary artery bypass graft (CABG) surgery.
| Serious Effects |
["Hypersensitivity to diclofenac or any component of the formulation","History of asthma, urticaria, or other allergic-type reactions after taking aspirin or other NSAIDs","Active gastrointestinal bleeding, ulceration, or perforation","Advanced renal disease","Perioperative pain in the setting of coronary artery bypass graft (CABG) surgery","Third trimester of pregnancy (risk of premature closure of ductus arteriosus)"]
| Precautions | ["Cardiovascular thrombotic events (MI, stroke) – avoid in patients with recent MI, unstable angina, or significant coronary artery disease.","Gastrointestinal ulceration, bleeding, and perforation – use lowest effective dose for shortest duration.","Hypertension and fluid retention – monitor blood pressure.","Renal toxicity – caution in patients with renal impairment, dehydration, or concurrent use of nephrotoxic drugs.","Hepatic toxicity – monitor liver enzymes; discontinue if severe hepatic injury occurs.","Anaphylactoid reactions – cross-sensitivity with aspirin and other NSAIDs."] |
Loading safety data…
| Fetal Monitoring | Monitor maternal renal function, blood pressure, and platelet count. Fetal ultrasound for ductus arteriosus and amniotic fluid volume if used beyond 20 weeks gestation. Assess for neonatal complications: bleeding, renal impairment, pulmonary hypertension. |
| Fertility Effects | Diclofenac may impair female fertility via inhibition of prostaglandin synthesis affecting ovulation and implantation. Reversible upon discontinuation. No known effect on male fertility. |