Interferon side effects

Hi everyone!

I´ve been on interferon for 2 months now and I´ve got all kinds of side effects. My doctor says interferon is the only disease modulating medicine for Polycythaemia vera (PV), so I take it, but I wonder about HOW modulating it is… but he cannot tell me. I take 45 mg of Pegasys per week, the minimum dosis.
I´m also looking at long term effects of this drug, e.g on the liver.
My ALT levels were 50 units before I began the treatment, and now 110, (normal max levels are 70) so I wonder what the long term effect will be on the liver.


Hi @GreatDane and a great big welcome to our forum.
You ask some great questions that I certainly cannot answer and are really for your medical team as they know all your medical history.
It helps me to write down everything I want to ask beforehand.
How are you feeling now?
I find that my emotions are on high alert since my diagnosis and when I see my blood test results I can get rather anxious, it’s the not knowing that gets me.
If you would like to speak to someone the Blood Cancer support line is there for you on 0808 2080 888.
Look after yourself and please let us know how you get on.


Side effects can be horrible can’t they and I can understand you asking questions about it. When will you get the opportunity to talk to your consultant? As @Erica advised, write down all of those questions :blush:

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Good evening GreatDane, and welcome to the forum.

I have a different MPN to your one, ET (and wish it would go home!), but have been on Pegasys for a little over 5 years now. The dosage has varied over that time but has been at 90mg every three weeks for the last year or so now, although it has been as low as 45mg every two weeks, up to as high as 90mg every week!
The most obvious side effect that I live with is extreme fatigue, not helped by my comorbidity of heart disease, as well as a heart attack 6 months or so before my ET diagnosis.
To your concern regarding your liver: my consultant ensures a close eye is kept on my liver function, with the aim to keep my ALT down to a tolerable “high” level of around the 80-90 mark. However it has been up at the 150+ mark before now. From conversations with my Haematologist and the Hepatologist, I see the latter annually, there seems to be a “conflict” between keeping my platelet count under control, whilst not letting my ALT get too high.
From the various scans I have had over the last few years my liver and my spleen are both enlarged, but whether that is from the cancer itself or the treatment for the cancer is open to debate.

As always, remember to smile and not take life too seriously.

Take care everyone.


Hi @GreatDane hope you’re well and thanks for posting

I am 41 and was diagnosed with Polycythaemia vera (PV) 3 years ago. I was on interferon for 18months and on the same dosage as you and though I still had the odd venesection now and then all my levels were doing ok. I didn’t really have many side effects but did notice increase in itchiness when my iron levels were crazy stupid low. I was then off it for a year and saw platelet count increase so had a choice of hydroxycarbamide or back on the interferon. I really didn’t want any form of chemo and knew what to expect with interferon and so back on it.

Regarding long term effects… to my knowledge it’s still unknown as interferon is still relatively new and prescribed to younger and as an alternative to hydroxy.

My liver and kidney is regularly monitored and though my levels head in the wrong direction at times they are still within the normal range so no flags of concerns


Hello @GreatDane
Thank for posting these important questions, I can see the Forum community are giving you their valuable experiences.
I am really sorry to hear you are experiencing side effects. May I ask whether you have spoken to your Haematologist or Clinical Nurse Specialist about this? I would suggest that the questions regarding long term effects and the current side effects should also be asked to the Clinical team looking after you. In the meantime I have some resources from our colleagues at MPN Voice that may be helpful:
Interferon alpha – MPN Voice
Layout 1 (
In particular the second link has a section on side effects on pages 6 and 7.
I hope this is helpful and take care,

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