Hydroxyurea vs aspirin question: This is my first... - MPN Voice

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Hydroxyurea vs aspirin question


This is my first post: I was diagnosed with ET two days ago. (Am male, age 62, in fairly good health and am active, despite a neuro-muscular disease - see below.) The oncologist here in the US prescribed low-dose aspirin and Hydrea (Hydroxyurea), which I started taking that day, i.e. I've been on it for two and a half days now (500mg twice a day). But when I woke up after my first night on Hydra, I noticed pronounced weakness in my left leg, which is the weaker of my two legs due to the neuro-muscular disease mentioned above (Charcot-Marie-Tooth disease). And the weakness remains. So while I wait for some input from my neurologist regarding whether Hydrea is counter-indicated (nothing about it appears on any CMT forum), what I really want to know is this: what is the Hydrea doing for me that the low-dose aspirin wouldn't do if taken alone? In other words, if the aspirin were to get my platelets to a safe level (I test pretty consistently between 750-780), would the Hydrea still be necessary for some reason? I did ask this of my oncologist, a nice guy, during our meeting when he gave me the diagnosis, but his response didn't sink in. He seemed to be saying that for my age group, the aspirin + Hydrea is that standard care strategy. OK, but I'll just reemphasize my question: what does the Hydrea do for me that the aspirin doesn't? Any informed opinions very welcome. (I acknowledge that the sudden weakness in my leg may be a coincidence and not linked to the Hydrea.)

15 Replies

Hi im not sure about the weakness in legs etc but i can answer your question on Asprin . it will do nothing to lower your your platelet count, The hydroxy does this , Asprin is to keep your blood thin, to help reduce the chances of a blood clot / stroke so yes you need to be on both meds like we all are with this mpn hope this helps regards Holly

Hi - I agree with Holly that the 2 drugs work in different ways - HU (or in my case Pegasys) reduces the number of platelets and aspirin makes them less sticky, so both are often needed. It's probably too early to know if HU suits you but if not it's worth considering alternatives such as Interferon/Pegasys or Anagrelide.

Good luck


the aspirin is to reduce stroke/clotting risk because your platelet levels are high and, as Andy says, may be an abnormal shape and so "sticky" and more likely to clot - it will not reduce the number of platelets. Hydroxy works differently: slows down your bone marrow so that it produces fewer blood components, notably platelets if u have ET, it may also reduce the risk of fibrosis in your bone marrow, which can be a longer term problem.

good luck

Just to add to the other replies which are all correct. I am only on aspirin to prevent blood clotting. Here in NZ it is not essential to go on HU. My platelets were 601 at last test so I am just watching and waiting at this stage.

sydlynne in reply to Lindiloo3

I'm in the US and also "watching & waiting" w/ platelet levels fluctuating between 600 and 850. This drives me crazy! I would much rather be proactive. It is like sitting in the middle of the road waiting to be hit by a bus. Why can't I just get out of the road?!

Sklines in reply to sydlynne

Wondering where you live in US. I live in Northeastern Pennsylvania. I have been treated at Geisinger Medical Center since 2012. Went to Memorial Sloan Kettering in NYC this week to be seen by Hemo that is more expert in this disease. Difficult to find MPN specialists.

Chuck309 in reply to sydlynne

I just got on this forum recently and see that I’m in the same situation as you. I go to a Hemotoligist every 4 months and have a blood test. I’m always somewhere between 525 to 650 I’m only on an aspirin and like you said have just waiting!!!! I’ve been like this for about 10 years. I’m in Florida and do like my Hemo, just curious, does your Hemo have some magic number where he says you will need to go on more meds?


It is my understanding that aspirin does not thin the blood it makes it less sticky so reducing the risk of clotting, as for muscular issues I get vibrating sensations as well as weakness, my neurologist recommend magnesium supplements and I have found this to be beneficial.

Good luck and have fun,


From my understanding, Hydrea affects the bone marrow, aspirin works in the blood.

Hydrea works to decrease bone marrow function - a good thing for MPNs since it is the bone marrow that is overproducing all red cells.

Aspirin is an anti-platelet (among other things) - and as others have said, it stops platelets in the blood from aggregating and forming clots (that's why some people call it a 'blood thinner'). It doesn't reduce platelets as it has no impact on the bone marrow.

So the two have separate functions in the body. I am on interferon and I still take my daily aspirin for the same reason: the interferon to get my bone marrow to stop overproducing my red cell line, and the aspirin to stop the high number of platelets already in my blood from aggregating and clotting.

I don't know anything about hydrea side effects and the muscle weakness. Sorry. Good luck finding out the cause. I hope you get some answers.

I'm 53 and in UK they have a watch and wait culture.. if your low risk. I take asprin.at present. had this Et since I was 50.

platelets are rising now 1020. so high. don't think you can blame Hu for weakness as it's a bit early yet.

take care


I'm on aspirin and Hydrea. It fascinates me how different consultants treat in different hospitals and even different countries. I'm on 3x 500mgs daily of HU and 4x at weekends and my platelets are 468! I've read that some consultants do not even treat with chemo unless platelets are over 800+. I have ET Jak2neg and no history of thrombosis or clotting.



Hello Isoruku, welcome to our forum, I can see that your question has been answered in that Hydroxycarbamide works by interfering with the production of DNA inside blood cells, this prevents the cells from continuing to grow and mature, leading to the death of the blood cell which is then removed by the body. Aspirin controls the 'stickiness' of the blood, people with MPNs have sticky blood meaning our blood is more likely to form clots, the stickiness is caused both by an increase in the number of blood cells and an increase in how likely these cells are to stick both to each other and to the blood vessel wall, Aspirin reduces the stickiness of blood cells, making them less likely to stick to each other and the blood vessel wall, Aspirin cannot alter the number of platelets and other blood cells in the body.

you can read and download all our treatment leaflets, including Hydroxycarbamide and Aspirin here...


With regards to the leg weakness, I do hope that you get an answer soon and get this sorted out.

Best wishes, Maz

Thanks everyone. Just got my first blood results back since going on the chemo, and my platelets are up to 830. Normally, I vary between 750 and 780. Will stay on the Hydrea but am planning to see my oncologist soon for a discussion. (And I am JAK 2 positive, not sure if I mentioned that before.)

The aspirin is only to make your platelets less sticky and keep them.from clotting. The hu will reduce your platelet counts. I take aspirin and 500mg. of hu daily. No side effects but I drink lots of water to reduce the risk of having them. Best of luck.

I blame Hu for weakness also, I am taking 3x500 a week and feel tired and weak.

Some light exercise helps as walking swimming.

Take care. Anastasia.

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