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. |
| Molecular Weight | 296.15 |
| 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 | Avoid in first trimester unless absolutely necessary; increased risk of miscarriage and malformations. |
| 2nd trimester | Use with caution; may cause oligohydramnios and premature ductus arteriosus constriction. |
| 3rd trimester | Avoid in third trimester; risk of premature closure of ductus arteriosus and oligohydramnios. |
Clinical note
Comprehensive clinical and safety monograph for VOLTAREN (VOLTAREN).
| Placental transfer | Diclofenac crosses the placenta; fetal serum levels are approximately 30% of maternal levels. |
| Breastfeeding | Diclofenac (Voltaren) is excreted into breast milk in low amounts; minimal risk to infant at recommended doses. Avoid high doses or prolonged use. |
| Lactation Rating |
■ 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 |
Known hypersensitivity to diclofenac or NSAIDsHistory of GI bleeding or perforation related to NSAIDsActive peptic ulcer diseaseSevere hepatic impairmentSevere renal impairment (eGFR <30 mL/min/1.73 m2)Coronary artery bypass graft (CABG) perioperative painThird trimester of pregnancy (risk of premature ductus arteriosus closure)
| 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. |
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| L2 (Safer) |
| 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). |
| 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. |
| Food/Dietary | Avoid alcohol. High-fat meals may delay absorption but not clinical effect. No other significant food interactions. |
| Clinical Pearls | Voltaren (diclofenac sodium) is a potent NSAID with preferential COX-2 inhibition. Use lowest effective dose for shortest duration due to cardiovascular and GI risks. Contraindicated in setting of coronary artery bypass graft surgery. Monitor renal function in elderly, volume-depleted patients, and those on ACE inhibitors or diuretics. Avoid concomitant use of other NSAIDs or aspirin. Topical formulation reduces systemic exposure but still carries some risk. |
| Patient Advice | Take Voltaren with food or milk to reduce stomach upset. · Avoid alcohol while taking this medication as it increases risk of stomach bleeding. · Do not take other NSAIDs or aspirin without consulting your doctor. · Contact your doctor immediately if you experience chest pain, weakness, slurred speech, or signs of stomach bleeding (e.g., black/bloody stools, vomiting coffee-ground material). · Use sunscreen and protective clothing as Voltaren may increase sun sensitivity. · Do not use topical Voltaren on open wounds, infected areas, or eyes. |