Hydroxyurea is a medication used to manage several serious health conditions, including certain cancers (such as chronic myeloid leukemia and head and neck cancers) and blood disorders (like sickle cell anemia and polycythemia vera). In sickle cell anemia, it helps reduce painful crises and the need for blood transfusions. For polycythemia vera, it controls excessive red blood cell production. Like all medications, hydroxyurea can cause side effects, and understanding these potential effects is important for individuals undergoing treatment.
Bone Marrow Suppression
The most common side effect of hydroxyurea is bone marrow suppression, also known as myelosuppression. This occurs because hydroxyurea interferes with DNA synthesis, affecting the growth of rapidly dividing cells. Since blood cells are continuously produced in the bone marrow, their production is particularly affected.
Bone marrow suppression decreases the number of white blood cells (leukopenia), red blood cells (anemia), and platelets (thrombocytopenia). The severity of this suppression can vary. This reduction affects the body’s ability to fight infection, transport oxygen, and clot blood.
Recognizing Symptoms and Monitoring
Patients taking hydroxyurea should recognize symptoms of low blood cell counts. Low white blood cells (neutropenia) increase infection risk, causing fever, chills, or a sore throat. Low red blood cell counts (anemia) can lead to fatigue, weakness, shortness of breath, dizziness, or pale skin.
A reduction in platelets (thrombocytopenia) can cause easy bruising, nosebleeds, bleeding gums, or small red spots (petechiae). Regular monitoring of blood counts is a standard part of treatment. Healthcare providers typically order complete blood count (CBC) tests regularly to track these levels and adjust the medication dose as needed.
Managing and Preventing Complications
Managing bone marrow suppression requires proactive measures and collaboration with a healthcare provider. To reduce infection risk from low white blood cell counts, practice good hand hygiene and avoid sick individuals. Proper food safety also helps prevent infections.
For anemia, prioritizing rest and conserving energy can help manage fatigue. If platelet counts are low, avoid injury-prone activities, use a soft-bristled toothbrush, and discuss all medications, including over-the-counter pain relievers, with a doctor. Healthcare providers may adjust the hydroxyurea dose or temporarily stop treatment to allow blood counts to recover.
Other Important Side Effects
Beyond bone marrow suppression, hydroxyurea can cause other side effects. Common skin changes include hyperpigmentation, dryness, or ulcers, particularly on the legs. Nail changes can also occur.
Gastrointestinal issues like nausea, vomiting, diarrhea, constipation, and loss of appetite are frequently reported. Some individuals may experience hair thinning or loss. Headaches and mouth sores are also possible side effects.
When to Contact Your Healthcare Provider
Contact a healthcare provider promptly if certain symptoms develop while taking hydroxyurea. Seek immediate medical attention for fever (above 100.4°F or 38°C), chills, or other infection signs. Unusual or excessive bleeding, such as persistent nosebleeds, bleeding gums, or blood in urine or stools, also warrants urgent contact.
Report severe or persistent fatigue, shortness of breath, or dizziness. Any new or worsening symptoms, including severe nausea, vomiting, or diarrhea, require medical consultation. Patients should never stop taking hydroxyurea or adjust their dose without first consulting their healthcare provider.