Zavedos

Zavedos - Precautions | Dosage | Side Effects

This article was medically reviewed by M.Pharm, Marko Tanaskovic on Sun, 19 Jan 2020. To read more about an author, click here.

Zavedos is a medicine containing an active substance called idarubicin hydrochloride. It belongs to a group of medicines called anthracyclines. It is used to treat different types of cancer because it works by preventing further growth of tumor cells. It is most commonly used in the treatment of acute myeloid leukemia as well as in the treatment of acute lymphoblastic leukemia.

Mechanism of Action and Pharmacokinetics

Zavedos works by interacting with an enzyme called topoisomerase II and inhibiting nucleic acid synthesis, thereby impeding tumor cell growth.

The elimination half-life of this drug is 22 hours. Zavedos is metabolized in the liver. Main metabolite produced in the liver is called idarubicinol. The main route of elimination is via the feces, while the smaller amount is excreted in the urine. As much as 97% of the drug binds to plasma proteins, and this fact should be kept in mind when using other drugs that also bind to plasma proteins in a high percentage, to avoid possible interactions.

Studies have shown that patients who have moderate or severe liver or kidney damage have significantly higher blood drug concentrations, which can lead to side effects. For this reason, the dose in these patients must be reduced.

Precautions

Zavedos should not be used in patients who have or have had bone marrow suppression, as Zavedos may worsen condition in these patients.

Zavedos should not be used in patients who have severe arrhythmias or other heart disease because of the cardiotoxicity of this medicine. In some cases, your doctor may decide to give you Zavedos even if you have an existing heart condition, if he / she thinks the benefit of treating leukemia is greater than the cardiotoxic risk.

Several cases of severe, fatal infections have been reported in patients taking this drug because Zavedos can lead to severe myelosuppression and significantly reduce the number of white blood cells that are the main line of defense against infection. Therefore, Zavedos should not be used in patients who have a severe or uncontrolled infection.

Patients who are allergic to idarubicin or other anthracyclines should not use Zavedos.

While you are on therapy with this drug, it is advisable to regularly check your complete blood count (in order to identify bone marrow supression in a timely manner) as well as your cardiac function (in order to identify any cardiotoxic effects of this drug in timely fashion).

Pregnancy and Breastfeeding

The FDA classifies this drug in Category D, which means that Zavedos should never be used during pregnancy. Zavedos exerts embryotoxic and teratogenic effects, and therefore its use in pregnancy is contraindicated.

It is advisable to use appropriate contraceptive methods while you are on therapy with this medicine to avoid pregnancy.

You should not breastfeed while you are being treated with this medicine because it is not known whether this medicine is excreted in breast milk. Due to the toxicity of this medicine, breastfeeding should be avoided while you are taking Zavedos.

Dosage

Zavedos exists in the form of intravenous injection but also in the form of capsules. The capsules are used in situations where intravenous administration is not possible.

Available forms and dosages include:

  • 5 mg capsules
  • 10 mg / 10 ml injection
  • 5 mg / 5 ml injection

Your oncologist will determine the dose that is best for you and explain how much and how often to use this medicine.

Injections must be given by professional medical staff. The dose is usually calculated based on your body surface area and is expressed in mg / m2. This is the most accurate way of dosing antineoplastic medications, such as Zavedos and only healthcare professionals can calculate the dose that is best for you.

If you are taking capsules, swallow the capsule whole, with plenty of liquid. You should wash your hands with soap, immediately after taking the capsule.

Interactions

As it may lead to arrhythmias, Zavedos should not be administered concomitantly with antiarrhythmic drugs such as amiodarone, ibutilide, bepridil, dofetilide, quinidine, dronedarone, procainamide, as well as with other drugs that have the potential to cause arrhythmias, including: cisapride (gastroprokinetic), cabozantinib (used to treat renal cell carcinoma), ceritinib (used to treat lung cancer).

Co-administration with a drug called clozapine (an antipsychotic) can lead to agranulocytosis, a condition characterized by very low white blood cells, which can result in weakening of the immune system and severe infections. For the same reason, Zavedos should not be used with medicines used in the treatment of rheumatoid arthritis (such as certolizumab and adalimumab).

Zavedos can interact with more than 70 medicines, and it is therefore very important that you inform your oncologist about any medicines you are taking.

Side Effects

Very common side effects include:

  • Infections
  • Anemia
  • Low blood platelet count
  • Low white blood cell count
  • Anorexia, nausea and vomiting
  • Red discolouration of the urine
  • Headache
  • Fever

Common side effects include:

  • Slow heartbeat
  • Rapid heartbeat
  • Arrhythmias
  • Heart failure
  • Hemorrhages
  • Thrombophlebitis
  • Gastrointestinal bleeding
  • Rash

Uncommon side effects include:

  • Sepsis
  • Dehydration
  • Increased uric acid concentration in the urine
  • Heart attack
  • Enterocolitis
  • Urticaria
  • Cellulitis

These are not all side effects. If you notice any other side effects, tell your doctor immediately.

References

  1. FDA
  2. TGA

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If you have any concerns or questions about your health, you should always consult with a physician or other health-care professional.