VOLTAREN-XR
Clinical safety rating: caution
Comprehensive clinical and safety monograph for VOLTAREN-XR (VOLTAREN-XR).
Nonsteroidal anti-inflammatory drug (NSAID) that inhibits cyclooxygenase (COX-1 and COX-2), reducing prostaglandin synthesis. This leads to anti-inflammatory, analgesic, and antipyretic effects.
| Metabolism | Hepatic metabolism primarily via CYP2C9, with minor contributions from CYP3A4. Conjugation with glucuronic acid and renal excretion of metabolites. |
| Excretion | Approximately 65% of a dose is excreted renally as unchanged drug and metabolites (primarily as glucuronide conjugates); about 35% is eliminated via bile in feces. |
| Half-life | The terminal elimination half-life is approximately 2 hours. The extended-release formulation (XR) does not alter the half-life; it maintains prolonged therapeutic plasma concentrations with twice-daily dosing. |
| Protein binding | Diclofenac is more than 99% bound to serum proteins, primarily albumin. |
| Volume of Distribution | The apparent volume of distribution is approximately 0.12–0.17 L/kg, indicating distribution primarily into extracellular fluid and high protein binding. |
| Bioavailability | Oral bioavailability is approximately 50% due to first-pass metabolism. With the XR formulation, absorption is complete but slower, yielding more sustained concentrations. |
| Onset of Action | Oral (XR tablet): Onset of analgesic effect is within 1 hour; peak effect occurs at 2-4 hours. For non-XR oral formulations, onset is within 30 minutes. |
| Duration of Action | Analgesic effect lasts up to 12 hours with the XR formulation due to sustained release; the extended duration allows twice-daily dosing. Anti-inflammatory effects are sustained with regular dosing. |
| Molecular Weight | 318.13 |
100 mg orally once daily, extended-release formulation. Maximum 150 mg/day (divided as 75 mg twice daily or 100 mg once daily).
| Dosage form | TABLET, EXTENDED RELEASE |
| Renal impairment | CrCl <30 mL/min: contraindicated. CrCl 30-59 mL/min: reduce dose to 50 mg once daily or 75 mg once daily; monitor renal function. CrCl >=60 mL/min: no adjustment. |
| Liver impairment | Child-Pugh Class A: no adjustment. Child-Pugh Class B: reduce dose by 50% (maximum 100 mg/day) and monitor. Child-Pugh Class C: contraindicated. |
| Pediatric use | Not recommended for children <1 year. For children >=1 year (systemic juvenile idiopathic arthritis): 1-2 mg/kg/day in two divided doses, maximum 3 mg/kg/day. Extended-release formulation not recommended for pediatric use. |
| Geriatric use | Initiate at lowest effective dose, typically 75-100 mg once daily. Maximum 100 mg/day. Consider renal function, increased risk of GI bleeding, and cardiovascular events. |
| 1st trimester | Avoid in first trimester unless absolutely necessary; associated with increased risk of miscarriage and cardiac malformations. |
| 2nd trimester | Use only if clearly needed; may cause oligohydramnios and premature closure of ductus arteriosus. |
| 3rd trimester | Contraindicated in third trimester due to risk of premature closure of ductus arteriosus, oligohydramnios, and neonatal renal impairment. |
Clinical note
Comprehensive clinical and safety monograph for VOLTAREN-XR (VOLTAREN-XR).
| Placental transfer | Diclofenac crosses the placenta; measurable concentrations in fetal plasma (approximately 1-3% of maternal levels). Transfer is higher in later gestation. |
| Breastfeeding | Diclofenac (active component) is excreted into breast milk in low amounts (0.03 mg/L after 50 mg dose). Theoretical risk of adverse effects in infant; avoid prolonged use or high doses. Use lowest effective dose for shortest duration. |
■ FDA Black Box Warning
Increased risk of serious cardiovascular thrombotic events, including myocardial infarction and stroke, which can be fatal. Risk increases with duration of use and in patients with cardiovascular disease or risk factors. Also, increased risk of serious gastrointestinal adverse events including bleeding, ulceration, and perforation of the stomach or intestines, which can be fatal.
| Serious Effects |
Known hypersensitivity to diclofenac or other NSAIDsHistory of asthma, urticaria, or allergic-type reactions after aspirin or NSAIDsActive peptic ulcer, gastrointestinal bleeding, or perforationSevere heart failure (NYHA class III/IV)Advanced renal diseaseThird trimester pregnancyCoronary artery bypass graft (CABG) surgery
| Precautions | Cardiovascular events, GI injury/bleeding, hypertension, sodium and fluid retention, renal toxicity (especially in patients with impaired renal function, heart failure, liver dysfunction, or elderly), anaphylactoid reactions, skin reactions (e.g., Stevens-Johnson syndrome), hematologic events (anemia, bleeding), hepatic effects, asthma exacerbation, use in pregnancy (avoid in late pregnancy due to premature closure of ductus arteriosus). |
| Food/Dietary |
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| Lactation Rating | L2 (Safer) |
| Teratogenic Risk | First trimester: Increased risk of miscarriage and cardiac defects. Second and third trimesters: Premature closure of ductus arteriosus, oligohydramnios, neonatal renal impairment. Avoid after 30 weeks. |
| Fetal Monitoring | Monitor amniotic fluid index, fetal echocardiography for ductus arteriosus patency, and neonatal renal function if used near term. |
| Fertility Effects | Reversible inhibition of ovulation; may impair fertility via prostaglandin synthesis inhibition. Discontinuation restores normal ovulation. |
| Avoid concomitant ingestion of alcohol (increases GI bleeding risk). No specific food restrictions, but taking with food may decrease GI irritation. High-fat meals may delay absorption but do not affect extent of absorption. |
| Clinical Pearls | Voltaren-XR (diclofenac sodium extended-release) is an NSAID indicated for chronic pain conditions. Its extended-release formulation allows once-daily dosing. Use lowest effective dose for shortest duration. Monitor renal function, liver enzymes, and blood pressure. Avoid in patients with significant renal impairment (CrCl <30 mL/min), active peptic ulcer disease, or history of GI bleeding. Caution in elderly and those with cardiovascular risk factors. May mask signs of infection. |
| Patient Advice | Take with food or milk to reduce stomach upset. · Do not crush or chew the tablet; swallow whole. · Avoid alcohol while taking this medication. · Report any signs of stomach bleeding (black/tarry stools, vomit that looks like coffee grounds) or cardiovascular events (chest pain, shortness of breath). · Limit exposure to sunlight and use sunscreen; may cause photosensitivity. · Do not take other NSAIDs or aspirin without consulting your doctor. · Take exactly as prescribed; do not increase dose or frequency. |