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Hydroxyurea Side Effects

Not all side effects for hydroxyurea may be reported. You should always consult a doctor or healthcare professional for medical advice. Side effects can be reported to the FDA here.

For the Consumer

Applies to hydroxyurea: oral capsule, oral tablet

In addition to its needed effects, some unwanted effects may be caused by hydroxyurea. In the event that any of these side effects do occur, they may require medical attention.

You should check with your doctor immediately if any of these side effects occur when taking hydroxyurea:

More common
  • Cough or hoarseness
  • fever or chills
  • lower back or side pain
  • painful or difficult urination
Less common
  • Black, tarry stools
  • blackening of the fingernails and toenails
  • blood in the urine or stools
  • pinpoint red spots on the skin
  • sores in the mouth and on the lips
  • unusual bleeding or bruising
  • Confusion
  • convulsions (seizures)
  • difficulty with urination
  • dizziness
  • headache
  • joint pain
  • seeing, hearing, or feeling things that are not there
  • swelling of the feet or lower legs
Incidence not known
  • Bleeding under the skin
  • blisters on the skin
  • bluish or pale color on the skin of the fingers or toes
  • coldness of the fingers or toes
  • crater-like lesions on the skin
  • itching skin
  • numbness or tingling of the fingers or toes
  • pain in the fingers or toes
  • unusual tiredness or weakness
  • weight loss

If any of the following symptoms of overdose occur while taking hydroxyurea, get emergency help immediately:

Symptoms of overdose
  • Scaling of the skin on the hands and feet
  • severe darkening of skin color
  • soreness
  • sores in the mouth and on the lips
  • swelling of the palms and soles of the feet
  • violet flushing of the skin

Some of the side effects that can occur with hydroxyurea may not need medical attention. As your body adjusts to the medicine during treatment these side effects may go away. Your health care professional may also be able to tell you about ways to reduce or prevent some of these side effects. If any of the following side effects continue, are bothersome or if you have any questions about them, check with your health care professional:

More common
  • Diarrhea
  • drowsiness
  • loss of appetite
  • nausea or vomiting
Less common
  • Constipation
  • redness of skin at the place of irradiation
  • skin rash and itching

For Healthcare Professionals

Applies to hydroxyurea: compounding powder, oral capsule, oral tablet


Hematologic side effects have been the most common reported and have included neutropenia, and very low reticulocyte and platelet levels, which required discontinuation of therapy. Elevated mean corpuscular volume of red cells have also been reported.[Ref]

Hematologic recovery usually occurred within two weeks.[Ref]


Gastrointestinal side effects have included stomatitis, anorexia, nausea, vomiting, diarrhea, and constipation. Both fatal and nonfatal pancreatitis have been reported in HIV-infected patients who received hydroxyurea in combination with antiretroviral agents.[Ref]


Vasculitic toxicities were reported most often in patients with a history of, or currently receiving, interferon therapy.[Ref]

Other side effects have included cutaneous vasculitic toxicities such as vasculitic ulcerations and gangrene, which have occurred in patients with myeloproliferative disorders during therapy with hydroxyurea.[Ref]


Dermatologic side effects including maculopapular rash, skin ulceration, dermatomyositis-like skin changes, peripheral erythema, squamous dysplasia, nail pigmentation, and facial erythema have been reported. In patients who have received several years of long-term daily maintenance therapy, hyperpigmentation, atrophy of skin and nails, scaling and violet papules have been reported. Alopecia has been reported very rarely. A case of transverse melanonychia has also been reported.[Ref]


Oncologic side effects have included skin cancer. Use of hydroxyurea has been mutagenic, clastogenic, and cause cellular transformation to a tumorigenic phenotype. The drug has been reported to be unequivocally genotoxic and a presumed transspecies carcinogen, which implies a carcinogenic risk to humans.[Ref]


Genitourinary side effects have been reported to occasionally include a temporary impairment of renal tubular function accompanied by elevations in serum uric acid, BUN, and creatinine levels. Dysuria has been reported very rarely.[Ref]


General side effects have included fever, chills, malaise, edema, asthenia, and moderate drowsiness following large doses.[Ref]

Nervous system

Nervous system side effects including headache, dizziness, disorientation, hallucinations, and convulsions have been reported very rarely. Severe peripheral neuropathy has been reported in HIV-infected patients who received hydroxyurea in combination with antiretroviral agents.[Ref]


Hepatic side effects have included elevation of hepatic enzymes. Both fatal and nonfatal hepatotoxicity have been reported in HIV-infected patients who received hydroxyurea in combination with antiretroviral agents. Fatal hepatic events were reported most often in patients treated with the combination of hydroxyurea, didanosine, and stavudine. This combination should be avoided.[Ref]


Respiratory side effects have rarely included the development of acute pulmonary infiltrates, fever, dyspnea, and pulmonary fibrosis.[Ref]


Metabolic side effects including two cases of tumor lysis syndrome have been reported.[Ref]


1. "Product Information. Droxia (hydroxyurea)." Bristol-Myers Squibb, Princeton, NJ.

2. Best PJ, Daoud MS, Pittelkow MR, Petitt RM "Hydroxyurea-induced leg ulceration in 14 patients." Ann Intern Med 128 (1998): 29-32

3. OBranski EE, Ware RE, Prose NS, Kinney TR "Skin and nail changes in children with sickle cell anemia receiving hydroxyurea therapy." J Am Acad Dermatol 44 (2001): 859-61

4. Teo RY, Tan E "A case of hydroxyurea-induced transverse melanonychia." Int J Dermatol 45 (2006): 1329-30

5. Sanchez-Palacios C, Guitart J "Hydroxyurea-associated squamous dysplasia." J Am Acad Dermatol 51 (2004): 293-300

6. Ceulen RP, Frank J, Poblete-Gutierrez P "Nail pigmentation due to hydroxycarbamide." Int J Dermatol 46 Suppl 3 (2007): 13-5

7. SemhounDucloux S, Ducloux D, Miguet JP "Mycophenolate mofetil-induced dyshidrotic eczema." Ann Intern Med 132 (2000): 417

8. Seidler AM, Gottlieb AB "Dermatomyositis induced by drug therapy: a review of case reports." J Am Acad Dermatol 59 (2008): 872-80

9. Bahadoran P, Castanet J, Lacour JPH, Perrin C, Delgiudice P, Mannocci N, Fuzibet JG, Ortonne JP "Pseudo-dermatomyositis induced by long-term hydroxyurea therapy: report of two cases." Br J Dermatol 134 (1996): 1161-3

10. Lossos IS, Matzner Y "Hydroxyurea-induced fever: case report and review of the literature." Ann Pharmacother 29 (1995): 132-3

11. Kavuru MS, Gadsden T, Lichtin A, Gephardt G "Hydroxyurea-induced acute interstitial lung disease." South Med J 87 (1994): 767-9

12. Seki JT, Al-Omar HM, Amato D, Sutton DM "Acute Tumor Lysis Syndrome Secondary to Hydroxyurea in Acute Myeloid Leukemia." Ann Pharmacother 37 (2003): 675-678

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