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Intron A Dosage

Generic name: Interferon alfa-2b 38ug in 1mL;
Dosage form: injection

The information at Drugs.com is not a substitute for medical advice. Always consult your doctor or pharmacist.

General

IMPORTANT: INTRON® A is supplied as 1) Powder for Injection/Reconstitution; 2) Solution for Injection in Vials. Not all dosage forms and strengths are appropriate for some indications. It is important that you carefully read the instructions below for the indication you are treating to ensure you are using an appropriate dosage form and strength.

To enhance the tolerability of INTRON A, injections should be administered in the evening when possible.

To reduce the incidence of certain adverse reactions, acetaminophen may be administered at the time of injection.

The solution should be allowed to come to room temperature before using.

Hairy Cell Leukemia

(see DOSAGE AND ADMINISTRATION, General)

Dose

The recommended dose for the treatment of hairy cell leukemia is 2 million IU/m2 administered intramuscularly or subcutaneously 3 times a week for up to 6 months. Patients with platelet counts of less than 50,000/mm3 should not be administered INTRON A intramuscularly, but instead by subcutaneous administration. Patients who are responding to therapy may benefit from continued treatment.

Dosage Forms for This Indication
Dosage Form Concentration Route Fixed Doses
Powder 10 MIU (single dose) 10 MIU/mL IM, SC N/A
Solution 18 MIU multidose 6 MIU/mL IM, SC N/A
Solution 25 MIU multidose 10 MIU/mL IM, SC N/A

NOTE: INTRON A Powder for Injection does not contain a preservative. The vial must be discarded after reconstitution and withdrawal of a single dose.

Dose Adjustment

  • If severe adverse reactions develop, the dosage should be modified (50% reduction) or therapy should be temporarily withheld until the adverse reactions abate and then resume at 50% (1 MIU/m2 TIW).
  • If severe adverse reactions persist or recur following dosage adjustment, INTRON A should be permanently discontinued.
  • INTRON A should be discontinued for progressive disease or failure to respond after six months of treatment.

Malignant Melanoma

(see DOSAGE AND ADMINISTRATION, General)

INTRON A adjuvant treatment of malignant melanoma is given in two phases, induction and maintenance.

Induction Recommended Dose

The recommended daily dose of INTRON A in induction is 20 million IU/m2 as an intravenous infusion, over 20 minutes, 5 consecutive days per week, for 4 weeks (see Dose Adjustment below).

Dosage Forms for This Indication
Dosage Form Concentration Route
Powder 10 MIU 10 MIU/mL IV
Powder 18 MIU 18 MIU/mL IV
Powder 50 MIU 50 MIU/mL IV

NOTE: INTRON A Solution for Injection in vials is NOT recommended for intravenous administration and should not be used for the induction phase of malignant melanoma.

NOTE: INTRON A Powder for Injection does not contain a preservative. The vial must be discarded after reconstitution and withdrawal of a single dose.

Dose Adjustment

NOTE: Regular laboratory testing should be performed to monitor laboratory abnormalities for the purpose of dose modifications (see PRECAUTIONS, Laboratory Tests).

  • INTRON A should be withheld for severe adverse reactions, including granulocyte counts greater than 250/mm3 but less than 500/mm3 or SGPT/SGOT greater than 5–10× upper limit of normal, until adverse reactions abate. INTRON A treatment should be restarted at 50% of the previous dose.
  • INTRON A should be permanently discontinued for:
    • Toxicity that does not abate after withholding INTRON A
    • Severe adverse reactions which recur in patients receiving reduced doses of INTRON A
    • Granulocyte count less than 250/mm3 or SGPT/SGOT of greater than 10× upper limit of normal

Maintenance Recommended Dose

The recommended dose of INTRON A for maintenance is 10 million IU/m2 as a subcutaneous injection three times per week for 48 weeks (see Dose Adjustment below).

Dosage Forms for This Indication
Dosage Form Concentration Route Fixed Doses
*
Patients receiving 50% dose reduction only
Patients receiving full dose only
Powder 10 MIU (single dose)* 10 MIU/mL SC N/A
Powder 18 MIU (single dose) 18 MIU/mL SC N/A
Solution 18 MIU multidose 6 MIU/mL SC N/A
Solution 25 MIU multidose 10 MIU/mL SC N/A

NOTE: INTRON A Powder for Injection does not contain a preservative. The vial must be discarded after reconstitution and withdrawal of a single dose.

Dose Adjustment

NOTE: Regular laboratory testing should be performed to monitor laboratory abnormalities for the purpose of dose modifications (see PRECAUTIONS, Laboratory Tests section).

  • INTRON A should be withheld for severe adverse reactions, including granulocyte counts greater than 250/mm3 but less than 500/mm3 or SGPT/SGOT greater than 5–10× upper limit of normal, until adverse reactions abate. INTRON A treatment should be restarted at 50% of the previous dose.
  • INTRON A should be permanently discontinued for:
    • Toxicity that does not abate after withholding INTRON A
    • Severe adverse reactions which recur in patients receiving reduced doses of INTRON A
    • Granulocyte count less than 250/mm3 or SGPT/SGOT of greater than 10× upper limit of normal

Follicular Lymphoma

(see DOSAGE and ADMINISTRATION, General)

Dose

The recommended dose of INTRON A for the treatment of follicular lymphoma is 5 million IU subcutaneously three times per week for up to 18 months in conjunction with anthracycline-containing chemotherapy regimen and following completion of the chemotherapy regimen.

Dosage Forms for This Indication
Dosage Form Concentration Route Fixed Doses
Powder 10 MIU (single dose) 10 MIU/mL SC N/A
Solution 18 MIU multidose 6 MIU/mL SC N/A
Solution 25 MIU multidose 10 MIU/mL SC N/A

NOTE: INTRON A Powder for Injection does not contain a preservative. The vial must be discarded after reconstitution and withdrawal of a single dose.

Dose Adjustment

  • Doses of myelosuppressive drugs were reduced by 25% from a full-dose CHOP regimen, and cycle length increased by 33% (e.g., from 21 to 28 days) when alpha interferon was added to the regimen.
  • Delay chemotherapy cycle if neutrophil count was less than 1500/mm3 or platelet count was less than 75,000/mm3.
  • INTRON A should be permanently discontinued if SGOT exceeds greater than 5× the upper limit of normal or serum creatinine greater than 2.0 mg/dL (see WARNINGS).
  • Administration of INTRON A therapy should be withheld for a neutrophil count less than 1000/mm3, or a platelet count less than 50,000/mm3.
  • INTRON A dose should be reduced by 50% (2.5 MIU TIW) for a neutrophil count greater than 1000/mm3, but less than 1500/mm3. The INTRON A dose may be re-escalated to the starting dose (5 million IU TIW) after resolution of hematologic toxicity (ANC greater than 1500/mm3).

Condylomata Acuminata

(see DOSAGE and ADMINISTRATION, General)

Dose

The recommended dose is 1.0 million IU per lesion in a maximum of 5 lesions in a single course. The lesions should be injected three times weekly on alternate days for 3 weeks. An additional course may be administered at 12 to 16 weeks.

Dosage Forms for This Indication
Dosage Form Concentration Route
Powder 10 MIU (single dose) 10 MIU/mL IL
Solution 25 MIU multidose 10 MIU/mL IL

NOTE: INTRON A Powder for Injection does not contain a preservative. The vial must be discarded after reconstitution and withdrawal of a single dose.

NOTE: Do not use the following formulations for this indication:

  • the 18 million or 50 million IU Powder for Injection
  • the 18 million IU multidose INTRON A Solution for Injection

Dose Adjustment

None

Technique for Injection

The injection should be administered intralesionally using a Tuberculin or similar syringe and a 25-to 30-gauge needle. The needle should be directed at the center of the base of the wart and at an angle almost parallel to the plane of the skin (approximately that in the commonly used PPD test). This will deliver the interferon to the dermal core of the lesion, infiltrating the lesion and causing a small wheal. Care should be taken not to go beneath the lesion too deeply; subcutaneous injection should be avoided, since this area is below the base of the lesion. Do not inject too superficially since this will result in possible leakage, infiltrating only the keratinized layer and not the dermal core.

AIDS-Related Kaposi's Sarcoma

(see DOSAGE and ADMINISTRATION, General)

Dose

The recommended dose of INTRON A for Kaposi's Sarcoma is 30 million IU/m2/dose administered subcutaneously or intramuscularly three times a week until disease progression or maximal response has been achieved after 16 weeks of treatment. Dose reduction is frequently required (see Dose Adjustment below).

Dosage Forms for This Indication
Dosage Form Concentration Route
Powder 50 MIU 50 MIU/mL IM, SC

NOTE: INTRON A Solution for Injection in vials should NOT be used for AIDS-Related Kaposi's Sarcoma.

NOTE: INTRON A Powder for Injection does not contain a preservative. The vial must be discarded after reconstitution and withdrawal of a single dose.

Dose Adjustment

  • INTRON A dose should be reduced by 50% or withheld for severe adverse reactions.
  • INTRON A may be resumed at a reduced dose if severe adverse reactions abate with interruption of dosing.
  • INTRON A should be permanently discontinued if severe adverse reactions persist or if they recur in patients receiving a reduced dose.

Chronic Hepatitis C

(see DOSAGE and ADMINISTRATION, General)

Dose

The recommended dose of INTRON A for the treatment of chronic hepatitis C is 3 million IU three times a week (TIW) administered subcutaneously or intramuscularly. In patients tolerating therapy with normalization of ALT at 16 weeks of treatment, INTRON A therapy should be extended to 18 to 24 months (72 to 96 weeks) at 3 million IU TIW to improve the sustained response rate (see CLINICAL PHARMACOLOGY, Chronic Hepatitis C). Patients who do not normalize their ALTs or have persistently high levels of HCV RNA after 16 weeks of therapy rarely achieve a sustained response with extension of treatment. Consideration should be given to discontinuing these patients from therapy.

When INTRON A is administered in combination with REBETOL®, patients with impaired renal function and/or those over the age of 50 should be carefully monitored with respect to the development of anemia. See REBETOL prescribing information for dosing when used in combination with REBETOL for adults and pediatric patients.

Dosage Forms for This Indication
Dosage Form Concentration Route Fixed Doses
Solution 18 MIU multidose 6 MIU/mL IM, SC N/A

Dose Adjustment

If severe adverse reactions develop during INTRON A treatment, the dose should be modified (50% reduction) or therapy should be temporarily discontinued until the adverse reactions abate. If intolerance persists after dose adjustment, INTRON A therapy should be discontinued.

Chronic Hepatitis B Adults

(see DOSAGE and ADMINISTRATION, General)

Dose

The recommended dose of INTRON A for the treatment of chronic hepatitis B is 30 to 35 million IU per week, administered subcutaneously or intramuscularly, either as 5 million IU daily (QD) or as 10 million IU three times a week (TIW) for 16 weeks.

Dosage Forms for This Indication
Dosage Form Concentration Route Fixed Doses
Powder 10 MIU (single dose) 10 MIU/mL IM, SC N/A
Solution 25 MIU multidose 10 MIU/mL IM, SC N/A

NOTE: INTRON A Powder for Injection does not contain a preservative. The vial must be discarded after reconstitution and withdrawal of a single dose.

Chronic Hepatitis B Pediatrics

(see DOSAGE and ADMINISTRATION, General)

Dose

The recommended dose of INTRON A for the treatment of chronic hepatitis B is 3 million IU/m2 three times a week (TIW) for the first week of therapy followed by dose escalation to 6 million IU/m2 TIW (maximum of 10 million IU TIW) administered subcutaneously for a total duration of 16 to 24 weeks.

Dosage Forms for This Indication
Dosage Form Concentration Route Fixed Doses
Powder 10 MIU (single dose) 10 MIU/mL SC N/A
Solution 25 MIU multidose 10 MIU/mL SC N/A

NOTE: INTRON A Powder for Injection does not contain a preservative. The vial must be discarded after reconstitution and withdrawal of a single dose.

Dose Adjustment

If severe adverse reactions or laboratory abnormalities develop during INTRON A therapy, the dose should be modified (50% reduction) or discontinued if appropriate, until the adverse reactions abate. If intolerance persists after dose adjustment, INTRON A therapy should be discontinued.

For patients with decreases in white blood cell, granulocyte or platelet counts, the following guidelines for dose modification should be followed:

INTRON A Dose White Blood Cell Count Granulocyte Count Platelet Count
Reduce 50% <1.5 × 109 /L <0.75 × 109 /L <50 × 109 /L
Permanently Discontinue <1.0 × 109 /L <0.5 × 109 /L <25 × 109 /L

INTRON A therapy was resumed at up to 100% of the initial dose when white blood cell, granulocyte, and/or platelet counts returned to normal or baseline values.

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