What’s the difference between Hydrea, Droxia, and Siklos?

[Droxia](https://dailymed.nlm.nih.gov/dailymed/fda/fdaDrugXsl.cfm?setid=740e054b-faac-7c27-f06d-a56efb699355&type=display), [Siklos](https://dailymed.nlm.nih.gov/dailymed/fda/fdaDrugXsl.cfm?setid=76957c0d-0f98-4376-bb06-eee651adc09d&type=display), and [Hydrea](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=b9514ae5-79ae-4cc2-9d7f-c8f7806d1694) are three different brands that contain the same active medication, hydroxyurea. The main difference is that Hydrea is used to treat certain types of cancer, while Droxia and Siklos are used to treat people with [sickle cell anemia](https://www.hematology.org/education/patients/anemia/sickle-cell-disease). Speak with your provider about the best treatment option for your condition.

hydroxyurea

Generic Hydrea

Used for Leukemia, Ovarian Cancer, Sickle Cell Disease, Skin Cancer, Thrombocythemia

Hydroxyurea (Hydrea) is an oral anticancer treatment option used for chronic myeloid leukemia (CML) and head and neck cancers. It can be used by itself or in combination with other anticancer medications and radiation, depending on the type of cancer. Although hydroxyurea (Hydrea) is available as a convenient oral medication, it has serious risks like low blood cell counts that can lead to infections and bleeding.

Reviewed by:

Jenny Zhang, PharmD, BCOP

Cydnee Ng, PharmD

Last reviewed on October 17, 2022

What is Hydroxyurea (Hydrea)?

What is Hydroxyurea (Hydrea) used for?

Chronic myeloid leukemia (CML)
Head and neck cancers (in combination with chemotherapy and radiation)

How Hydroxyurea (Hydrea) works

Hydroxyurea (Hydrea) is an antimetabolite. The way it works to treat certain cancers isn't fully clear, but it's thought to interfere with the way cells make their genetic material (DNA), leading to cell death.

Are you looking for information on Droxia (hydroxyurea) instead?

Drug facts

Common Brands	Hydrea
Drug Class	Anticancer
Controlled Substance Classification	Not a controlled medication
Generic Status	Lower-cost generic available
Availability	Prescription only

Common Brands

Hydrea

Drug Class

Anticancer

Controlled Substance Classification

Not a controlled medication

Generic Status

Lower-cost generic available

Availability

Prescription only

Side effects of Hydroxyurea (Hydrea)

The following side effects may get better over time as your body gets used to the medication. Let your healthcare provider know immediately if you continue to experience these symptoms or if they worsen over time.

Common Side Effects

Low blood counts
Infections
Nausea
Vomiting
Diarrhea
Constipation
Lack of appetite
Headache

Less Common Side Effects

Ulcers in the mouth (also called mouth sores)
Rash
Skin and nail changes
Fever
Chills
Fatigue

Hydroxyurea (Hydrea) serious side effects

Contact your healthcare provider immediately if you experience any of the following.

Serious infections (due to low blood cell counts): repeated fevers, chills, cough, trouble breathing, severe diarrhea, vomiting, painful or frequent urination
Serious bleeds: bleeding or bruising that doesn’t stop or go away, large amount of bleeding, throwing up blood, bloody or black and tarry stool
Lung problems: fever, cough, shortness of breath, other breathing problems

Source: DailyMed

The following Hydroxyurea (Hydrea) side effects have also been reported

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur:

More common

Black, tarry stools

blood in the urine or stools

chills

cough

fever

hoarseness

lower back or side pain

painful or difficult urination

pale skin

pinpoint red spots on the skin

sore throat

ulcers, sores, or white spots in the mouth

unusual bleeding or bruising

unusual tiredness or weakness

Less common

Blackening of the fingernails and toenails

troubled breathing with exertion

Rare

Confusion

dizziness

headache

joint pain

seeing, hearing, or feeling things that are not there

seizures

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

drowsiness

fast heartbeat

hives, itching, skin rash

irritation

itching, pain, redness, or swelling on the leg

joint stiffness or swelling

loss of appetite

muscle spasms (tetany) or twitching seizures

nausea

numbness or tingling of the fingers or toes

pain in the fingers or toes

sore on the leg

swelling of the eyelids, face, lips, hands, or feet

tightness in the chest

trembling

troubled breathing or swallowing

vomiting

weight loss

Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common

Diarrhea

Less common

Constipation

redness of skin at the place of radiation

weight gain

Incidence not known

Absent, missed, or irregular menstrual periods

bluish-brownish bands on the nails

hair loss or thinning of hair

indigestion

passing of gas

stomach pain, fullness, or discomfort

stopping of menstrual bleeding

Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.

Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

Get your GoodRx coupon

Avg retail price

$74.07(Save 71.15%)

GoodRx discount

$21.37

See prices

Pros and cons of Hydroxyurea (Hydrea)

Pros

Convenient oral medication
Available as a generic
Lower rates of nausea and vomiting compared to other anticancer medications

Cons

Requires blood tests for regular monitoring during treatment
Can raise your risk of infection or bleeding
Not safe during pregnancy or breastfeeding

Pharmacist tips for Hydroxyurea (Hydrea)

Swallow hydroxyurea (Hydrea) capsules whole. Don’t open, dissolve, or chew the capsules because the medication can cause serious harm if it’s not taken properly.
Make sure to do your blood tests on time so your provider can monitor your blood counts during your treatment with hydroxyurea (Hydrea).
Since hydroxyurea (Hydrea) can lower your blood cell counts and weaken your immune system, you might be more likely to develop an infection and have trouble fighting it off. To lower your chances of developing an infection, wash your hands often, and avoid crowded places and people who are sick. Avoid food-borne illnesses by washing raw fruits and vegetables before eating, and cooking foods thoroughly.
Speak with your provider before getting any vaccines and make sure they know you’re taking hydroxyurea (Hydrea). This medication can weaken your immune system and affect how you respond to vaccines. Live vaccines like Varivax (chickenpox vaccine) might lead to a severe infection while you're taking hydroxyurea (Hydrea).
If you’re going to be outside, be sure to wear sunscreen with at least sun protective factor (SPF) 15 and protective clothing like long sleeves, pants, hats, and sunglasses. This can lower your risk of sun damage and skin cancer since hydroxyurea (Hydrea) might raise your risk for skin cancer.
If you or your partner is able to become pregnant, make sure to use birth control while using hydroxyurea (Hydrea). You'll also need to continue taking birth control for at least 6 months (females) or 1 year (males) after stopping the medication. This medication might cause harm to unborn babies.
Ask your provider or pharmacist about the best way to handle and throw away hydroxyurea (Hydrea) safely. You or your caregiver should wear disposable gloves when handling this medication. Make sure to wash hands with soap and water before and after handling. Anticancer medications can be very harmful to people who handle or come into contact with them.

Common questions about Hydroxyurea

Droxia, Siklos, and Hydrea are three different brands that contain the same active medication, hydroxyurea. The main difference is that Hydrea is used to treat certain types of cancer, while Droxia and Siklos are used to treat people with sickle cell anemia. Speak with your provider about the best treatment option for your condition.

Let your provider know if you have problems with your kidney. You’re at higher risk of side effects from Hydroxyurea and will need to be monitored more closely. With kidney problems, your body might have a harder time getting rid of this medication. This causes higher levels of Hydroxyurea in your body, which affects your risk of side effects. Depending on how severe your kidney problems are, you might need to take the medication at a lower dose. If you’re on dialysis, you can still take Hydroxyurea; make sure to take the medication after your dialysis session on your dialysis days.

Hydroxyurea isn’t recommended during pregnancy. Based on animal studies, it can cause harm to an unborn baby and shouldn’t be used in pregnancy. Let your provider know right away if you become pregnant during Hydroxyurea treatment, or if you have any questions about pregnancy while receiving the medication.

Hydroxyurea isn’t recommended while breastfeeding. It can pass into breast milk and can cause serious harm to nursing babies. Talk to your provider if you have any questions about other ways to feed your baby while receiving Hydroxyurea.

According to the National Comprehensive Cancer Network (NCCN), platinum-based therapies are the recommended treatment for head and neck cancers. This regimen is typically cisplatin (the platinum-based medication) in combination with radiation. Other options include cisplatin or carboplatin (another platinum-based medication) in combination with other chemotherapies, such as fluorouracil. Discuss with your provider to see which alternative treatment plan is right for you.

Risks and warnings for Hydroxyurea (Hydrea)

Hydroxyurea (Hydrea) can cause some serious health issues. This risk may be even higher for certain groups. If this worries you, talk to your doctor or pharmacist about other options.

Low blood cell counts

Risk factors: Previous radiation therapy or chemotherapy use

Hydroxyurea (Hydrea) can cause your white blood cell, red blood cell, and platelet counts to drop. When the number of these cells are lower than normal, you’re at risk of developing infections, anemia, and bleeding or bruising. Your provider will closely monitor your blood counts through routine lab work while you're taking hydroxyurea (Hydrea). If your blood counts are low, your dose might need to be lowered or you might stop taking the medication altogether. After stopping hydroxyurea (Hydrea), your blood cell counts should return to normal in a few days. Let your provider know as soon as possible if you experience bleeding and bruising that doesn’t stop or go away, blood in your urine, weakness, pale or yellowish skin, fevers, chills, or other signs of infection.

Risk for developing other cancers

Risk factors: Taking hydroxyurea (Hydrea) long term

Hydroxyurea (Hydrea) is carcinogenic, which means it has the ability to cause cancer. This doesn't mean it will cause cancer, but it might raise your risk for cancers like leukemia and skin cancer. Your risk is higher if you take hydroxyurea (Hydrea) for a long period of time. Make sure to wear protective clothing and sunscreen to lower your risk of skin damage and skin cancer. Speak to your provider if you’re concerned about your risk for other cancers.

Harm to unborn baby

Based on animal studies, hydroxyurea (Hydrea) can harm an unborn baby when taken during pregnancy. Because of these risks, if you’re a woman who can get pregnant, you’ll likely need to take a pregnancy test to make sure you’re not pregnant before you start the medication. In addition, regardless of your sex, you should use birth control during treatment with hydroxyurea (Hydrea) to prevent pregnancy. After treatment, continue to use birth control for at least another 6 months (for females) or 1 year (for males). Let your provider know right away if you or your partner becomes pregnant during this time.

Blood vessel damage and skin ulcers

Risk factors: Taking interferon medication

Hydroxyurea (Hydrea) has been used for certain blood cancers. When used this way, some people had blood vessel damage, including leg ulcers. Most people who reported these problems were either taking or had taken interferon medications. If you develop an open sore anywhere on your body while taking hydroxyurea (Hydrea), contact your provider.

Pancreas, liver, or nerve damage when taken with HIV medications

Risk factors: Taking medications for human immunodeficiency virus (HIV)

Pancreatitis (inflammation of the pancreas), liver damage, and nerve damage have happened in people who took hydroxyurea (Hydrea) while also taking antiretroviral medications (commonly used to treat HIV infection). If you experience stomach pain; nausea; vomiting; tingling in your arms, legs, hands, or feet; or yellowing of the whites of your eyes or skin, tell your provider so you can be checked for these problems.

Skin reactions after radiation therapy

Risk factors: Previous radiation therapy

If you’ve received radiation therapy before, taking hydroxyurea (Hydrea) can cause a flare-up of skin irritation around the areas where you had radiation. Let your provider know if you develop any redness or discomfort to areas of your skin while taking hydroxyurea (Hydrea).

Lung problems

When used for certain blood cancers, some people taking hydroxyurea (Hydrea) had lung damage and scarring (pulmonary fibrosis) during treatment. Notify your provider right away if you start experiencing a cough or difficulty breathing.

Hydroxyurea (Hydrea) dosage

The average cost for 60 capsules of 500mg of Hydroxyurea (Hydrea) is $21.37 with a free GoodRx coupon. This is 71.15% off the average retail price of $74.07.

Capsule

Dosage	Quantity	Price as low as	Price per unit
500mg	60 capsules	$21.37	$0.36

Typical dosage for Hydroxyurea (Hydrea)

The dose can vary depending on the type of cancer you have and your body weight. Your dose can also differ if you have kidney problems. Your healthcare provider will determine the appropriate dose for you.

Hydroxyurea (Hydrea) is taken by mouth once daily. It can be taken by itself, in combination with other anticancer medications, or with radiation therapy.

Interactions between Hydroxyurea (Hydrea) and other drugs

Hydroxyurea (Hydrea) may interact with certain medications or supplements. Always let your doctor and pharmacist know about any other medications or supplements (including prescribed and over-the-counter medications, vitamins, and dietary or herbal supplements) that you are currently taking. The list below does not include all possible drug interactions with Hydroxyurea (Hydrea). Please note that only the generic name of each medication is listed below.

Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking this medicine, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.

Using this medicine with any of the following medicines is not recommended. Your doctor may decide not to treat you with this medication or change some of the other medicines you take.

Measles Virus Vaccine, Live
Mumps Virus Vaccine, Live
Rotavirus Vaccine, Live
Rubella Virus Vaccine, Live
Varicella Virus Vaccine, Live
Zoster Vaccine, Live

Using this medicine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.