ENBREL
Clinical safety rating
cautionComprehensive clinical and safety monograph for ENBREL (ENBREL).
Comprehensive clinical and safety monograph for ENBREL (ENBREL).
Rheumatoid arthritis (moderate to severe active RA in adults, alone or with methotrexate)Polyarticular juvenile idiopathic arthritis (moderate to severe active JIA in patients aged 2 years and older)Psoriatic arthritis (active PsA in adults)Ankylosing spondylitis (active AS in adults)Plaque psoriasis (moderate to severe chronic plaque psoriasis in adults who are candidates for systemic therapy or phototherapy)
Allergic reaction, Upper respiratory tract infection, Itching, Rash, Injection site reaction
Tumor necrosis factor (TNF) inhibitor; etanercept is a dimeric fusion protein consisting of the extracellular ligand-binding portion of human TNF receptor p75 linked to the Fc portion of human IgG1. It binds to soluble and membrane-bound TNF, thereby blocking TNF-mediated inflammatory responses.
| Metabolism | Metabolism is via peptide hydrolysis and protein catabolism; no significant cytochrome P450 involvement. |
| Excretion | Renal: negligible; Biliary/Fecal: not significantly eliminated; primarily degraded via proteolysis into amino acids. |
| Half-life | Approximately 102 hours (range 68–170 hours) after subcutaneous administration in adults; prolonged in elderly and patients with renal impairment; supports every 2-week dosing. |
| Protein binding | ~96% bound, primarily to albumin and to a lesser extent to other plasma proteins. |
| Volume of Distribution | Approximately 0.18 L/kg (adults), indicating limited distribution primarily within the vascular and interstitial spaces; not extensively distributed into tissues. |
| Bioavailability | Subcutaneous: approximately 59% (range 50–76%) after a single 25 mg dose; absolute bioavailability not established for IV route; intramuscular route not recommended. |
| Onset of Action | Subcutaneous: clinical improvement may be observed as early as 1–2 weeks, with maximal effect by 12 weeks. |
| Duration of Action | Continuous therapeutic effect maintained with every 2-week dosing; drug levels decline below therapeutic threshold after ~4–6 weeks after last dose. |
| Molecular Weight | 51234 |
| Action Class | Disease Modifying Anti-Rheumatoid Drugs (DMARDs)- Biologics |
| Brand Substitutes | Etacept PFS Injection, Intacept 50mg Injection, Etacept 25mg Injection, Etanerrel 25mg Injection, Enbrol 25mg Injection |
50 mg subcutaneous injection once weekly
| Dosage form | SYRINGE |
| Renal impairment | No dose adjustment required for renal impairment. Not studied in patients with severe renal impairment. |
| Liver impairment | No dose adjustment required for hepatic impairment. Not studied in patients with severe hepatic impairment. |
| Pediatric use | For juvenile idiopathic arthritis (JIA) patients aged 2 years and older: 0.8 mg/kg (max 50 mg) subcutaneously once weekly. |
| Geriatric use | No specific dose adjustment based on age alone; monitor for infections and adverse effects as elderly patients may have increased susceptibility. |
| 1st trimester | Minimal data; avoid unless clearly needed. Theoretical risk of infection in neonate due to maternal IgG crossing. |
| 2nd trimester | Limited data; consider risks vs benefits. May reduce efficacy of neonatal vaccination. |
| 3rd trimester | Avoid in late pregnancy; high placental transfer leads to detectable infant levels at birth; risk of neonatal immunosuppression and infection. |
Clinical note
Comprehensive clinical and safety monograph for ENBREL (ENBREL).
| Placental transfer | Actively transported by FcRn; significant transfer in second and third trimesters, leading to infant serum levels similar to maternal. |
| Breastfeeding | Excretion into breast milk is low but not well-studied. Use caution, especially in preterm infants or those with immunosuppression. |
| Lactation Rating | L3 - Limited Data |
| Teratogenic Risk | Etanercept is an IgG1 fusion protein that undergoes active placental transfer, increasing from the first to third trimester. Limited human data show no clear increase in major birth defects or miscarriage, but there is a potential for immunosuppression in the neonate if used in the third trimester. Animal studies show no teratogenicity. |
| Fetal Monitoring | Monitor for maternal infections, complete blood count, and liver function tests. In third-trimester exposure, monitor neonate for signs of immunosuppression (e.g., infections) and consider avoiding live vaccines in the first 6 months. |
| Fertility Effects | No known negative impact on fertility. TNF inhibitors may improve fertility in patients with inflammatory conditions by reducing disease activity. |
■ FDA Black Box Warning
Serious infections, including tuberculosis (TB), invasive fungal infections, and other opportunistic infections, have been reported. Patients should be screened for TB prior to therapy. Discontinue if serious infection develops. Malignancies, including lymphoma, have been reported in children and adolescents treated with TNF blockers.
| Serious Effects |
Sepsis or active serious infectionKnown hypersensitivity to etanercept or any component
| Precautions | Risk of serious infections (including TB, bacterial sepsis, invasive fungal infections), Hepatitis B reactivation, Malignancies (including lymphoma, leukemia, and other malignancies), Congestive heart failure (new onset or exacerbation), Demyelinating disorders (e.g., multiple sclerosis, optic neuritis), Hematologic abnormalities (including pancytopenia and aplastic anemia), Hypersensitivity reactions, Live vaccines should not be administered concurrently |
| Food/Dietary | No specific food interactions have been reported with ENBREL. However, because ENBREL affects the immune system, patients should practice food safety to reduce infection risk (e.g., avoid undercooked meats, unpasteurized dairy). |
| Clinical Pearls | ENBREL (etanercept) is a TNF-alpha inhibitor used for rheumatoid arthritis, psoriatic arthritis, ankylosing spondylitis, plaque psoriasis, and polyarticular juvenile idiopathic arthritis. Monitor for infections, including tuberculosis reactivation. Do not administer live vaccines during therapy. Injection site reactions are common. If switching from other TNF inhibitors, consider washout period. ENBREL can be used in combination with methotrexate but avoid with other biologics. |
| Patient Advice | ENBREL is given as a subcutaneous injection, typically once or twice weekly. Proper injection technique and rotation of sites are important. · Do not take live vaccines (e.g., MMR, nasal flu, varicella) while on ENBREL. · Seek medical attention if you develop signs of infection (fever, chills, cough) or allergic reactions (rash, difficulty breathing). · Report any new or worsening neurological symptoms, such as numbness, tingling, or vision changes. |
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