Interferon Beta-1A Dosage

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Usual Adult Dose for:

Usual Pediatric Dose for:

Additional dosage information:

Usual Adult Dose for Multiple Sclerosis

Avonex(R): 30 mcg IM once a week

Titration dose to reduce the incidence and severity of influenza-like symptoms:
Week 1: 7.5 mcg IM once a week
Week 2: 15 mcg IM once a week
Week 3: 22.5 mcg IM once a week
Week 4+: 30 mcg IM once a week

Rebif(R): 22 mcg or 44 mcg subcutaneously 3 times a week

Titration dose for 22 mcg:
Weeks 1 to 2: 4.4 mcg subcutaneously 3 times a week
Weeks 3 to 4: 11 mcg subcutaneously 3 times a week
Weeks 5+: 22 mcg subcutaneously 3 times a week

Titration dose for 44 mcg:
Weeks 1 to 2: 8.8 mcg subcutaneously 3 times a week
Weeks 3 to 4: 22 mcg subcutaneously 3 times a week
Weeks 5+: 44 mcg subcutaneously 3 times a week

Usual Adult Dose for Neuritis

(Not approved by FDA)

Optic neuritis:
Study (n=192)
Avonex(R): 30 mcg IM once a week

Usual Pediatric Dose for Multiple Sclerosis

(Not approved by FDA)

Study (n=14)
Greater than 11 years:
Avonex(R): 30 mcg IM every week
Rebif(R): 22 mcg subcutaneously 3 times a week

Greater than 10.5 years:
Avonex(R): 15 mcg IM every week

Study (n=51)
Greater than 8.1 years:
Rebif(R): 22 mcg subcutaneously 3 times a week, up to 44 mcg subcutaneously 3 times a week, for a mean duration of 1.8 years (range 1 month to 4.4 years)

Renal Dose Adjustments

Data not available

Liver Dose Adjustments

Rebif(R): The manufacturer recommends caution when initiating this drug in patients with active liver disease, a history of significant liver disease, alcohol abuse, or increased serum SGPT (greater than 2.5 times ULN).

Dose Adjustments

Rebif(R): Leukopenia or elevated liver function tests may require dose reduction or discontinuation of Rebif(R) administration until toxicity has resolved.

Precautions

Rebif(R) and the lyophilized vial formulation of Avonex(R) are contraindicated in patients with a history of hypersensitivity to albumin (human).

Anaphylaxis has been reported as a rare complication of interferon beta-1a. Other allergic reactions have included dyspnea, orolingual edema, skin rash, and urticaria, and have ranged from mild to severe. Several allergic reactions (some severe) have occurred after prolonged use. Interferon beta-1a should be discontinued if anaphylaxis or other allergic reactions occur.

Interferon beta-1a should be used with caution in patients with depression. Depression, suicidal ideation, and suicide attempts have been reported in patients receiving interferon compounds. Patients should be advised to report immediately any symptoms of depression, suicidal ideation, and/or psychosis to their prescribing physicians. If a patient develops depression or other severe psychiatric symptoms, cessation of therapy should be considered.

Severe liver injury, including some cases of hepatic failure requiring liver transplantation, has been reported rarely in patients receiving Rebif(R). Symptoms of liver dysfunction began from 1 to 6 months after the initiation of therapy. If jaundice or other symptoms of liver dysfunction appear, treatment with Rebif(R) should be discontinued immediately due to the potential for rapid progression to liver failure. Reduction in dose should be considered if SGPT rises above 5 times ULN. The dose may be gradually increased when enzyme levels have normalized.

Patients receiving Avonex(R) should be monitored for signs and symptoms of hepatic injury. Severe hepatic injury, including cases of hepatic failure, has been reported rarely. Asymptomatic elevation of hepatic transaminases has also been reported, and in some patients has recurred upon rechallenge with Avonex(R).

The potential risk of interferon beta-1a used in combination with known hepatotoxic drugs or other products (e.g., alcohol) should be considered prior to starting interferon beta-1a, or when adding new hepatotoxic agents to the regimen of a patient already on interferon beta-1a.

Patients with preexisting congestive heart failure should be monitored for worsening of their cardiac condition during initiation of and continued treatment with Avonex(R). While beta interferons do not have any known direct cardiac toxicity, some cases of congestive heart failure, cardiomyopathy, and cardiomyopathy with congestive heart failure in patients without known predisposition have been temporally related to the administration of Avonex(R). Recurrence upon rechallenge has been reported in some patients.

Caution should be exercised in patients with preexisting seizure disorders when administering interferon beta-1a. Seizures have been temporally associated with the use of beta interferons.

Decreased peripheral blood counts in all cell lines (including rare pancytopenia and thrombocytopenia) have been reported in patients treated with Avonex(R) during postmarketing experience. Some cases recurred with rechallenge. Monitoring for signs or symptoms of decreased blood counts is recommended.

Regular monitoring for leukopenia and new or worsening thyroid abnormalities is recommended in patients treated with Rebif(R).

In addition to those laboratory tests normally required for monitoring multiple sclerosis patients, complete blood and differential white blood cell counts, platelet counts, and blood chemistries (including liver function tests) are recommended during interferon beta-1a therapy. Patients with myelosuppression may require more intensive monitoring of complete blood cell counts, with differential and platelet counts. Thyroid function should be monitored periodically. Thyroid function tests should be performed in patients who have or develop symptoms of thyroid dysfunction (hypo- or hyperthyroidism) according to standard medical practice.

Autoimmune disorders of multiple target organs have been reported in patients treated with Avonex(R) during postmarketing experience. These have included idiopathic thrombocytopenia, hyper- and hypothyroidism, and rare cases of autoimmune hepatitis. Treatment discontinuation should be considered in patients who develop a new autoimmune disorder.

Safety and effectiveness have not been established in pediatric patients (less than 18 years of age).

Dialysis

Data not available

Other Comments

Rebif(R) should be administered, if possible, at the same time (preferably in the late afternoon or evening) on the same 3 days (e.g., Monday, Wednesday, and Friday) at least 48 hours apart each week.

Pretreatment with analgesics and/or antipyretics on treatment days may ameliorate the influenza-like symptoms associated with interferon beta-1a use.

A small preliminary study suggests that in patients who develop serum neutralizing antibodies to the interferon beta drug they use, switching to an alternate interferon beta preparation may not be clinically beneficial.

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