Hydroxyurea. And Red Blood Cells

[Rainyday22]

Does Hydroxyurea lower red blood cells and how long does it take.

[hunter5582]

At age 77 with PV, cytoreduction is usually recommended. The common treatments include therapeutic phlebotomy, hydroxyurea, Besremi or Pegasys, and Jakafi. Besremi and Jakafi are the only two FDA-approved medications for PV treatment in the USA.

Hydroxyurea does lower red blood cell counts. It also lowers platelets and white blood cell counts. HU is a cytotoxin (antimetabolite) that works by interfering with DNA activity in hematopoietic stem cells and other cells that have active DNA activity in the body. HU is a form of chemotherapy.

HU is in common use to treat PV, but in the USA its use is off-label as it is not FDA approved for this purpose. Some people tolerate HU and benefit from it. Some people are refractory to HU and/or are unable to tolerate it. HU is one of the faster acting cytoreductive medications but response rates vary. It is pretty common to start on 500mg/day and monitor at 2-week intervals. Doses are adjusted as needed based on the patient's response. It is also fairly common to also use therapeutic phlebotomy along with the HU to more specifically target the RBCs.

You will likely hear varied responses about HU on the forum. Some find it effective and tolerable. Others, myself included, do not. I have done much better on the interferons (Pegasys/Besremi). IFNs have been more effective and much easier to tolerate for me. Note that we are each different in how we respond to these medications. You cannot predict your own response by what others have experienced.

Here is a bit of information on hydroxyurea that you may find helpful.

drugs.com/monograph/hydroxy...

online.epocrates.com/drugs/...

If you decide to opt for HU, here is some additional information that is important to know.

oralchemoedsheets.com/sheet...

ethrombo.blogspot.com/2017/...

Suggest that you review all of your treatment options with your care team. Compare the benefits and risks of each treatment option and do your own analysis of which treatment option you prefer based on your treatment goals, risk tolerance, and preferences. Hopefully, you already have a MPN Specialist on your care team. MPNs are rae disorders and most doctors, including hematologists, have little experience with them. Just in case, here are two lists,

mpnforum.com/list-hem./

pvreporter.com/mpn-speciali...

All the best to you as you move forward.

[EPguy]

It usually will lower RBCs, along with platelets and white blood cells as Hunter says. How much it lowers each varies between patients. I was on it and it lowered PLT, but strangely my RBC and WBC went down just before I started it.

If you're RBC, HCT is really high your Dr may start you on a high dose to get it to the safe range faster. But you will watch for adverse effects as Hunter says.

I'm now on Besremi, after just over a year on HU.

[DoubleF79]

I can’t help but feel this question is best directed to your medical professional. How long is a piece of string?

[Meatloaf9]

In my case I started HU about 18 months ago, it took 2 weeks for my RBC's and blood counts to start dropping and about 3-4 months for all blood counts to go into the normal range.

My blood counts have stayed normal and level for about 6-12 months now on the same dose of HU (9 per week). I am 73 PV.

I asked my mpn specialist about a month ago if I should switch to interferon and his advice was to stay on the HU. We are all different in how we respond to medications.

This is in no way any type of advice, this is just my experience with HU.

My advice would be to have this discussion with your hematologist/mpn specialist.

[Ayla13]

Hi Rainyday22,

My red blood cells went down from 4.2 to 3.8 the first month on HU then to 3.5 the second , then to 3.1 the third , and they have stayed at 3.1 for two years now . I walk daily and eat more iron rich foods if I feel too tired. I’m 64 yrs , Calr 1 mutation and take 1000 mg of Hu on weekdays ;500 mg on weekend . Hope this helps . I know we all react differently . Good luck 🤞