BETASERON
Clinical safety rating: caution
Comprehensive clinical and safety monograph for BETASERON (BETASERON).
Interferon beta-1b binds to type I interferon receptors, inducing expression of immunomodulatory proteins, reducing T-cell activation and pro-inflammatory cytokines, and enhancing blood-brain barrier integrity.
| Metabolism | Renal proteolytic degradation; no known hepatic metabolism. |
| Excretion | Interferon beta-1b is primarily cleared via renal catabolism. Less than 1% of the dose is excreted unchanged in urine. Biliary/fecal excretion is negligible. |
| Half-life | The terminal elimination half-life is approximately 8 minutes to 4.3 hours following subcutaneous administration, with a mean of 1.2 hours. The short half-life necessitates frequent dosing to maintain clinical effect in multiple sclerosis. |
| Protein binding | >95% bound to serum albumin and beta-globulins. |
| Volume of Distribution | Approximately 0.25 L/kg, indicating limited extravascular distribution, consistent with a large protein restricted primarily to plasma and interstitial fluid. |
| Bioavailability | Subcutaneous: approximately 50% (range 30–65%) following injection, with substantial interindividual variability. |
| Onset of Action | Subcutaneous: Clinical effects on magnetic resonance imaging (MRI) lesion activity are observed within 2–6 weeks. Symptomatic improvement may take several months. |
| Duration of Action | The pharmacodynamic effects, such as downregulation of interferon-inducible genes, persist for 2–3 days after a single dose. For clinical outcomes, continuous treatment is required to suppress relapses. |
250 mcg subcutaneous every other day
| Dosage form | VIAL |
| Renal impairment | No specific dose adjustment recommended; use with caution in severe renal impairment. |
| Liver impairment | No specific dose adjustment recommended; use with caution in severe hepatic impairment. |
| Pediatric use | Not approved for use in pediatric patients under 18 years of age. |
| Geriatric use | No specific dose adjustment recommended; limited data in elderly patients. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for BETASERON (BETASERON).
| Breastfeeding | Interferon beta-1b is excreted into breast milk in very low amounts. The milk-to-plasma ratio (M/P) is not well defined but likely <0.1. Due to its high molecular weight and low oral bioavailability, the risk to a nursing infant is minimal. However, caution is advised; benefits of breastfeeding should be weighed against the need for the drug. |
| Teratogenic Risk | Interferon beta-1b (Betaseron) is associated with an increased risk of spontaneous abortion in animal studies. In human pregnancies, data are limited but do not suggest a major teratogenic risk; however, use only if clearly needed. First trimester: Possible risk of abortion; no evidence of congenital malformations. Second and third trimesters: No known specific fetal risks, but consider potential maternal adverse effects like anemia. |
■ FDA Black Box Warning
None.
| Serious Effects |
["Hypersensitivity to interferon beta-1b or human albumin","Pregnancy (Category C)"]
| Precautions | ["Hepatic injury including severe hepatitis and hepatic failure","Anaphylaxis and other allergic reactions","Depression and suicide risk","Injection site necrosis","Leukopenia","Thyroid disorders","Seizures","Congestive heart failure","Monitor liver function tests and blood counts"] |
| Food/Dietary | No significant food interactions. Grapefruit juice does not affect metabolism. Maintain balanced diet to support overall health. |
| Clinical Pearls |
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| Fetal Monitoring | Monitor complete blood count (CBC), liver function tests (LFTs), and thyroid function tests (TFTs) at baseline and periodically. During pregnancy, monitor for signs of infection or worsening of MS symptoms. Fetal monitoring: Ultrasound for fetal growth and well-being as per standard obstetrical care, with additional fetal non-stress test if maternal complications arise. |
| Fertility Effects | In animal studies, interferon beta-1b caused dose-dependent anovulatory effects and decreased fertility, but these effects were reversible. In humans, no dedicated fertility studies exist; however, no significant impact on fertility has been reported in clinical use. |
| Betaseron (interferon beta-1b) is used for relapsing forms of multiple sclerosis. Titrate dose over 2-3 weeks to minimize flu-like symptoms; premedicate with acetaminophen or ibuprofen. Injection site reactions are common; rotate sites and avoid injecting into scarred or tender areas. Monitor liver function tests and complete blood counts periodically. Not for use in pregnancy; advise effective contraception. |
| Patient Advice | Administer subcutaneously every other day, preferably at bedtime. · Rotate injection sites among arms, abdomen, thighs, and hips to reduce reactions. · Flu-like symptoms (fever, chills, myalgia) are common initially; take acetaminophen or ibuprofen before and after injection. · Store vials in refrigerator; do not freeze. Let reach room temperature before injecting. · Report any signs of infection, unusual bruising, or jaundice to your healthcare provider. · Do not stop or change dosing without consulting your doctor. |