Interferon Alfa-2a
Indications
Interferon Alfa-2a is used for:
Renal cell carcinoma, Chronic hepatitis B, Chronic hepatitis C, Hairy cell leukaemia, AIDS related Kaposi's sarcoma, Chronic myeloid leukaemia, Follicular lymphoma, Cutaneous T-cell lymphoma, Melanoma
Adult Dose
Subcutaneous
Renal cell carcinoma
Adult: As an adjunct to cytotoxic chemotherapy: In an escalating dose of 3 million units 3 times wkly for 1 wk, then 9 million units 3 times wkly for 1 wk, then 18 million units 3 times wkly thereafter for 3-12 mth.
Chronic hepatitis B
Adult: 2.5-5 million units/m2 3 times/wk for 4-6 mth.
Chronic hepatitis C
Adult: 3-4.5 million units 3 times wkly for 6 mth when used with ribavirin. As monotherapy: Initial: 3-6 million units 3 times wkly for 6 mth followed by 3 million units 3 times wkly for an additional 6 mth, or 3 million units 3 times wkly for 12 mth.
Hairy cell leukaemia
Adult: 3 million units daily for 16-24 wk. Maintenance: 3 million units 3 times/wk. May continue treatment for up to 24 wk.
AIDS-related Kaposi's sarcoma
Adult: In an escalating dose of 3 million units daily for 3 days, 9 million units daily for 3 days, 18 million units daily for 3 days, and 36 million units daily, if tolerated, on days 10-84. thereafter the max tolerated dose (up to 36 million units) may be given 3 times wkly.
Chronic myeloid leukaemia
Adult: In an escalating dose of 3 million units daily for 3 days, 6 million units daily for 3 days, and 9 million units daily thereafter. For responders after 12 wk: Continue treatment until a complete haematological response is achieved or for a max of 18 mth; for those who achieve a complete haematological response: Continue on 9 million units daily (at least 9 million units 3 times wkly) in order to achieve a cytogenetic response.
Follicular lymphoma
Adult: As an adjunct to chemotherapy: 6 million units/ m2 daily on days 22-26 of each 28-day chemotherapy cycle.
Cutaneous T-cell lymphoma
Adult: In an escalating dose of 3 million units daily for 3 days, then 9 million units daily for 3 days, and then 18 million units daily to complete 12 wk of treatment. Thereafter, the max tolerated dose (up to 18 million units) is given 3 times wkly for at least 12 mth in responders.
Melanoma
Adult: 3 million units 3 times/wk for 18 mth. Start treatment no later than 6 wk after surgery.
Child Dose
Renal Dose
Administration
Contra Indications
Hypersensitivity. Autoimmune hepatitis, hepatic decompensation.
Precautions
History of depression (monitor for signs). Perform regular neuropsychiatric monitoring. Seizure disorders and/or compromised CNS function. Preexisting or any history of cardiac disease. Monitor CBC prior to and during therapy. Myelosuppression or concurrent use of myelosuppressive drugs. Hypothyroidism, hyperthyroidism, DM. Perform ophthalmological exam on patients with preexisting ophthalmologic disorders (e.g. diabetic or hypertensive retinopathy). Monitor patients with impaired renal function. Creatinine clearance <50 ml/min. May impair ability to drive or operate machinery. Pregnancy and lactation.
Pregnancy-Lactation
Interactions
Reduces clearance of theophylline. Enhanced myelosuppression with other myelosuppressive drugs (e.g. zidovudine). Drugs metabolised by CYP450 pathway (monitor for changes in pharmacologic or adverse effects of concomitant drug). Increased risk of toxicity of centrally acting drugs. Increased risk of renal failure with interleukin-2.
Side Effects
Side effects of Interferon Alfa-2a :
Depressive illness, suicidal behaviour, irritability, insomnia, anxiety. Flu-like symptoms. Headache, dizziness, paraesthesia, confusion, impaired concentration, alteration in taste or smell. GI disturbances. Dryness of oropharynx, epistaxis, rhinitis, arrhythmia, sinusitis. Inj site reaction, alopecia, rash, dry skin or pruritus. Conjunctivitis, menstrual irregularity, visual disturbances. Coughing, dyspnoea. Myalgia, joint or bone pain, arthritis or polyarthritis. Bone marrow depression.
Potentially Fatal: Marked increase in triglyceride levels, GI haemorrhage, severe infections, pulmonary infiltrates or pulmonary function impairment.
Mode of Action
Interferon alfa-2a has antiviral, antitumour and immunomodulatory activity. It inhibits replication of a wide range of RNA and DNA viruses. It also exerts antiproliferative effects on normal and malignant cells. Interferon alfa-2a suppresses antibody formation through an effect on B-lymphocytes and inhibits onset of delayed hypersensitivity.