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 |
| Molecular Weight | 318.13 |
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 | Avoid; NSAIDs generally not recommended due to potential risk of miscarriage and cardiovascular malformations. |
| 2nd trimester | Use only if clearly needed; minimal risk but may cause oligohydramnios. |
| 3rd trimester | Avoid; may cause premature closure of ductus arteriosus, oligohydramnios, and fetal renal dysfunction. |
Clinical note
Comprehensive clinical and safety monograph for FLECTOR (FLECTOR).
| Placental transfer | Diclofenac crosses the placenta; animal studies show transfer, human data limited. |
| Breastfeeding | Low levels in breast milk; however, due to potential adverse effects on infant's cardiovascular and renal systems, caution is advised. Use only if clearly needed. |
| Lactation Rating |
■ 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 |
Hypersensitivity to diclofenac or any componentHistory of asthma, urticaria, or allergic-type reactions after taking aspirin or other NSAIDsPerioperative pain in the setting of coronary artery bypass graft (CABG) surgeryActive peptic ulcer disease or gastrointestinal bleeding
| 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) |
| Food/Dietary | No known food interactions. However, avoid alcohol as it may increase risk of gastrointestinal bleeding when used with systemic NSAIDs. |
Loading safety data…
| L2 (Safer) |
| 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. |
| 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. |
| Clinical Pearls | Apply topically only to intact skin; avoid contact with eyes and mucous membranes. Do not use with other topical products or occlusive dressings. Maximum dose is 4 patches daily (2 patches per side per day for the lower extremities). Remove before bathing or swimming. Do not apply to open wounds or infected areas. |
| Patient Advice | Apply the patch to clean, dry skin over the most painful area. · Do not cut or trim the patch. · Wash hands after handling the patch. · Remove the patch after 12 hours and apply a new one if needed. · Do not use more than 4 patches per day. · Avoid exposing the application site to direct heat sources. · Do not use with other topical pain relievers or heating pads. · Contact healthcare provider if rash, blistering, or excessive irritation occurs. |