INTERFERONS

Alpha-interferon--2 forms in US:

• Alfa-2a (Roferon-A)
• Alfa-2b (Intron-A)

Side f/x:

1. Flu-like sx (fever, chills, malaise, HA, arthralgias, myalgia, tachycardia)
2. Alopecia
3. Myelosuppression
4. Infection
5. Autoimmunity (rare; mostly thyroid)
6. Seizures (rare)
7. Cardiac failure (rare)
8. Renal failure (rare)
9. Retinopathy
10. Interstitial pulmonary fibrosis
11. Hearing impairment
12. Psychiatric (20-30% of pts--apathy, cognitive changes, depression)
    1. Paroxetine 10mg QD titrated upward starting 2wks before and continuing to end of IFN treatment was ass'd with sig. lower incidence of depression in a randomized trial of 38 pts with malignant melanoma receiving IFN (NEJM 344:961, 2001--JW)
13. Paradoxical worsening of HCV hepatitis

Pegylated IFN 

• Interferon with an attached polyethylene glycol moiety; increases half-life
• Can be given Qwk not 3x/wk like regular IFN
• IFN alfa-2b PEG = "PEG-Intron"
• IFN alfa-2a PEG = "Pegasys"