Istodax blocks certain enzymes in the body and interferes with the growth of tumor cells.

Istodax is a prescription medicine used to treat cutaneous T-cell lymphoma (CTCL) affecting the skin.. It is usually given after at least one other cancer treatment did not work or has stopped working.

It is not known if Istodax is safe and effective in children under 18 years of age.

Before you receive Istodax, tell your doctor if you have an electrolyte imbalance, a personal or family history of "Long QT syndrome," heart disease, kidney disease, or liver disease.

Do not receive Istodax if you are pregnant. It could harm the unborn baby. Use effective birth control, and tell your doctor if you become pregnant during treatment. Hormonal forms of contraception (such as birth control pills, injections, implants, skin patches, and vaginal rings) may not be effective enough to prevent pregnancy during your treatment. Ask your doctor about using a non-hormone method of birth control (such as a condom, diaphragm, spermicide) to prevent pregnancy while taking Istodax.

Before taking this medicine

To make sure Istodax is safe for you, tell your doctor if you have ever had:

• heart problems or a heart rhythm disorder;

• long QT syndrome (in you or a family member);

• kidney disease;

• liver disease (especially hepatitis B);

• an electrolyte imbalance (such as high or low levels of potassium or magnesium in your blood); or

• if you are sick with nausea, vomiting, or diarrhea.

You may need to have a negative pregnancy test 7 days before starting this treatment.

Both men and women using Istodax should use effective birth control to prevent pregnancy. Men should use condoms. Romidepsin can harm an unborn baby if the mother or father is using this medicine.

Keep using birth control for at least 1 month after your last dose. Tell your doctor right away if a pregnancy occurs.

Istodax can make hormonal birth control less effective, including birth control pills, injections, implants, skin patches, and vaginal rings. Use barrier birth control to prevent pregnancy: condom, diaphragm, cervical cap, or contraceptive sponge.

Pregnancy may be less likely to occur while the mother or the father is using Istodas. Both men and women should still use birth control to prevent pregnancy because the medicine can harm an unborn baby.

You should not breastfeed while using Istodax, and for at least 1 week after your last dose.

Istodax is injected into a vein by a healthcare provider.

This medicine must be given slowly over 4 hours.

Istodax is given in a 28-day treatment cycle. You will receive an injection only on certain days of this cycle.

You may be given other medicine to prevent nausea or vomiting while you are receiving Istodax.

Drink plenty of liquids in the 3 days after each Istodax injection.

You may get infections more easily, even serious or fatal infections. You will need frequent medical tests. Your heart function may also need to be checked using an electrocardiograph or ECG (sometimes called an EKG).

If you've had hepatitis B, it may come back or get worse. You may need liver function tests while using Istodax and for several months after you stop.

Usual Adult Dose of Istodax for Cutaneous T-cell Lymphoma:

14 mg/m2 IV over 4 hours on days 1, 8, and 15 of a 28-day cycle; repeat cycle every 28 days provided patient continues to benefit and is tolerating therapy

Uses: For the treatment of cutaneous T-cell Lymphoma (CTCL) and peripheral T-cell lymphoma (PTCL) in patients who have received at least 1 prior systemic therapy.

Usual Adult Dose of Istodax for Peripheral T-cell Lymphoma:

14 mg/m2 IV over 4 hours on days 1, 8, and 15 of a 28-day cycle; repeat cycle every 28 days provided patient continues to benefit and is tolerating therapy

Uses: For the treatment of cutaneous T-cell Lymphoma (CTCL) and peripheral T-cell lymphoma (PTCL) in patients who have received at least 1 prior systemic therapy.

To make sure Istodax is safe for you, tell your doctor if you have ever had:

• heart problems or a heart rhythm disorder;

• long QT syndrome (in you or a family member);

• kidney disease;

• liver disease (especially hepatitis B);

• an electrolyte imbalance (such as high or low levels of potassium or magnesium in your blood); or

• if you are sick with nausea, vomiting, or diarrhea.

You may need to have a negative pregnancy test 7 days before starting this treatment.

Both men and women using Istodax should use effective birth control to prevent pregnancy. Men should use condoms. Romidepsin can harm an unborn baby if the mother or father is using this medicine.

Keep using birth control for at least 1 month after your last dose. Tell your doctor right away if a pregnancy occurs.

Istodax can make hormonal birth control less effective, including birth control pills, injections, implants, skin patches, and vaginal rings. Use barrier birth control to prevent pregnancy: condom, diaphragm, cervical cap, or contraceptive sponge.

Pregnancy may be less likely to occur while the mother or the father is using Istodas. Both men and women should still use birth control to prevent pregnancy because the medicine can harm an unborn baby.

You should not breastfeed while using Istodax, and for at least 1 week after your last dose.

Call your doctor for instructions if you miss an appointment for your Istodax injection.

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

Follow your doctor's instructions about any restrictions on food, beverages, or activity.

Get emergency medical help if you have signs of an allergic reaction to Istodax: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

You may get infections more easily, even serious or fatal infections, during and after treatment. Call your doctor right away if you have signs of infection such as:

• fever, flu symptoms, muscle aches;

• worsening skin symptoms;

• burning when you urinate; or

• cough, chest discomfort, feeling short of breath.

Also call your doctor at once if you have:

• chest pain, feeling short of breath;

• fast or pounding heartbeats, fluttering in your chest, sudden dizziness (like you might pass out);

• low blood cell counts - fever, chills, tiredness, mouth sores, skin sores, easy bruising, unusual bleeding, pale skin, cold hands and feet, feeling light-headed or short of breath;

• signs of tumor cell breakdown - tiredness, weakness, muscle cramps, nausea, vomiting, diarrhea, fast or slow heart rate, tingling in your hands and feet or around your mouth.

Common Istodax side effects may include:

• low blood cells counts, infections;

• nausea, vomiting, loss of appetite;

• constipation;

• itching;

• tiredness; or

• changes in your sense of taste.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Istodax can cause a serious heart problem. Your risk may be higher if you also use certain other medicines for infections, asthma, heart problems, high blood pressure, depression, mental illness, cancer, malaria, or HIV.

Tell your doctor about all your current medicines. Many drugs can interact with romidepsin, especially:

• dexamethasone or other steroid medicine;

• St. John's wort;

• an antibiotic or antifungal medicine;

• an antidepressant;

• a blood thinner (warfarin, Coumadin, Jantoven);

• heart rhythm medicine;

• HIV or AIDS medicine;

• seizure medicine; or

• tuberculosis medicine.

This list is not complete and many other drugs may interact with romidepsin. This includes prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible drug interactions are listed here.