How Do Cytidine Deaminase Inhibitors Work?

Cytidine deaminase inhibitors are a class of drugs used to treat adults with myelodysplastic syndrome (MDS). MDS is a group of blood/bone marrow disorders in which the bone marrow fails to produce enough healthy blood cells, making patients prone to infections, anemia (low red blood cell count), and easy bleeding/bruising, and it is characterized by signs and symptoms such as:

• Shortness of breath
• Constant tiredness or weakness 
• Unusual paleness (pallor) 
• Easy bruising or bleeding
• Petechiae (flat, pinpoint spots under the skin caused by bleeding) 

Cytidine deaminase inhibitors are a combination of two medications:

• Decitabine: It belongs to a class of medications called “hypomethylation agents” that work by helping the bone marrow to produce normal blood cells and by killing abnormal cells in the bone marrow. 
• Cedazuridine: It works by preventing the breakdown of decitabine, thus increasing its amount in the body.

Cytidine deaminase inhibitors are administered via oral route, typically once daily for the first five days of a 28-day treatment cycle.

Cytidine deaminase inhibitors work in the following ways:

• They work by inhibiting an enzyme called "cytidine deaminase" involved in the pyrimidine salvage pathway (thymidine is taken up by transport proteins and phosphorylated by the enzyme thymidine kinase to thymidine monophosphate).
• In addition, they facilitate the metabolism of hypomethylating agents by inducing DNA hypomethylation and apoptosis (a genetically regulated form of cell death) of cancerous cells.

Cytidine deaminase inhibitors are indicated for the treatment of adults with myelodysplastic syndrome.

Some of the common side effects include:

• Nausea
• Vomiting
• Constipation
• Diarrhea
• Headache
• Abdominal pain
• Tiredness/weakness
• Decreased appetite
• Mouth sores
• Muscle pain

Other rare side effects include:

• Dizziness 
• Fatigue 
• Rash/itching
• Anemia (low red blood cell count)
• Shortness of breath
• Chills, sore throat, fever, or cough
• Thrombocytopenia (low blood platelet count)
• Hypotension (low blood pressure)
• Increased liver enzymes
• Increased creatinine 
• Hypocalcemia (low blood calcium level)
• Hyponatremia (low blood sodium level)
• Hyperglycemia (high blood glucose level)
• Insomnia (trouble falling and/or staying asleep)
• Edema (swelling caused by excess fluid trapped in the body tissues)

Information contained herein is not intended to cover all possible side effects, precautions, warnings, drug interactions, allergic reactions, or adverse effects. Check with your doctor or pharmacist to make sure these drugs do not cause any harm when you take them along with other medicines. Never stop taking your medication and never change your dose or frequency without consulting your doctor.

Generic and brand names of cytidine deaminase inhibitors include:

• Cedazuridine
• Cedazuridine/decitabine
• Inqovi