FLECTOR
Clinical safety rating: caution
Comprehensive clinical and safety monograph for FLECTOR (FLECTOR).
Diclofenac is a nonsteroidal anti-inflammatory drug (NSAID) that inhibits cyclooxygenase (COX-1 and COX-2), thereby reducing prostaglandin synthesis, which mediates inflammation, pain, and fever.
| Metabolism | Diclofenac is primarily metabolized in the liver via CYP2C9 to 4'-hydroxydiclofenac and other hydroxylated metabolites, which are then conjugated. |
| Excretion | Renal (approximately 50% as unchanged drug and metabolites), biliary/fecal (approximately 40% as metabolites) |
| Half-life | Terminal elimination half-life is approximately 1.8–3.5 hours (mean 2.5 hours) in healthy adults; no significant accumulation with repeated dosing |
| Protein binding | >99%, primarily to albumin |
| Volume of Distribution | Approximately 0.1–0.2 L/kg, indicating limited distribution primarily to plasma and extracellular fluid |
| Bioavailability | Topical: approximately 1–3% of dose absorbed systemically; oral: 100% |
| Onset of Action | Topical: detectable plasma concentrations within 1 hour; clinical effect (pain relief) typically within 2–4 hours |
| Duration of Action | Topical: duration of effect is approximately 6–8 hours; dosing recommended every 12 hours |
Apply 1 sachet (10 g of 1.3% gel, equivalent to 130 mg diclofenac epolamine) to the affected area twice daily. Maximum duration: 7 days.
| Dosage form | SYSTEM |
| Renal impairment | No specific dose adjustments for topical application; caution in severe renal impairment (CrCl <30 mL/min) due to potential systemic accumulation. |
| Liver impairment | Contraindicated in Child-Pugh class C cirrhosis. In Child-Pugh class B, use with caution; avoid if active liver disease. |
| Pediatric use | Not recommended for use in children under 18 years of age due to lack of safety and efficacy data. |
| Geriatric use | No specific dose adjustment; apply the same adult dose. Monitor for skin irritation and systemic effects in elderly patients with renal or hepatic impairment. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for FLECTOR (FLECTOR).
| Breastfeeding | Diclofenac (active ingredient) is excreted into breast milk in low concentrations; relative infant dose estimated at 0.3-1.0% of maternal weight-adjusted dose. M/P ratio not explicitly reported. Considered compatible with breastfeeding by the American Academy of Pediatrics, but use lowest effective dose and monitor infant for adverse effects. |
| Teratogenic Risk | FDA Pregnancy Category C prior to 30 weeks gestation; Category D after 30 weeks gestation. First trimester: increased risk of cardiac defects and gastroschisis from NSAID use. Second trimester: possible fetal renal dysfunction and oligohydramnios. Third trimester: risk of premature ductus arteriosus closure, pulmonary hypertension, and oligohydramnios. Avoid use after 30 weeks gestation. |
■ FDA Black Box Warning
NSAIDs may cause an increased risk of serious cardiovascular thrombotic events, myocardial infarction, and stroke, which can be fatal. Risk may increase with duration of use and in patients with cardiovascular risk factors. FLECTOR is contraindicated for treatment of peri-operative pain in the setting of coronary artery bypass graft (CABG) surgery.
| Serious Effects |
["History of allergic reaction to diclofenac or other NSAIDs","Patients with asthma, urticaria, or other allergic-type reactions after taking aspirin or other NSAIDs","Peri-operative pain in the setting of CABG surgery","Late pregnancy (third trimester)"]
| Precautions | ["Cardiovascular thrombotic events","Gastrointestinal bleeding, ulceration, and perforation","Renal toxicity including electrolyte imbalance and acute renal failure","Anaphylactoid reactions","Hepatic effects including elevated liver enzymes and severe hepatic reactions","Serious skin reactions (e.g., exfoliative dermatitis, Stevens-Johnson syndrome)"] |
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| Fetal Monitoring | Monitor fetal ultrasound for oligohydramnios and ductus arteriosus flow if used during pregnancy. Assess maternal renal function and blood pressure regularly. Monitor infant for signs of NSAID toxicity if breastfeeding. |
| Fertility Effects | Reversible inhibition of ovulation and luteal phase defects due to prostaglandin synthesis inhibition. May delay or impair fertility; consider discontinuation in women attempting conception. |