Vidaza

Dosage for Azacitidine is highly individualized based on the patient's body surface area (BSA), the specific condition being treated, and the patient's tolerance to the medication.

Myelodysplastic Syndromes (MDS) and CMML (Injectable)

• Standard Starting Dose: 75 mg/m² administered daily for 7 days.
• Cycle Frequency: This 7-day treatment period is followed by a 21-day rest period, making a total cycle of 28 days.
• Duration: It is recommended that patients receive at least 4 to 6 cycles of treatment. Treatment may continue as long as the patient continues to benefit.

Acute Myeloid Leukemia (AML) Maintenance (Oral)

• Standard Dose: 300 mg taken orally once daily.
• Cycle Frequency: Taken for the first 14 days of a 28-day cycle.
• Note: Oral Azacitidine should not be substituted for injectable Azacitidine as the dosing and absorption profiles are entirely different.

Azacitidine is approved for pediatric patients (aged 1 month and older) with newly diagnosed juvenile myelomonocytic leukemia (JMML).

• Dosing: The dose is typically based on body surface area or weight. For JMML, the standard dose is often 75 mg/m² for patients weighing 10 kg or more, and 2.5 mg/kg for patients weighing less than 10 kg, administered daily for 7 days in a 28-day cycle.

Renal Impairment

Azacitidine and its metabolites are primarily excreted by the kidneys. Patients with pre-existing renal impairment must be monitored closely. If unexplained elevations in serum creatinine or blood urea nitrogen (BUN) occur, the dose may be reduced by 50% for the next cycle, or the cycle may be delayed until levels return to baseline.

Hepatic Impairment

Because Azacitidine is potentially hepatotoxic (toxic to the liver), especially in patients with extensive liver metastasis, caution is required. While specific GFR-like formulas for liver dosing are not standard, providers may delay or reduce doses if liver enzymes (ALT/AST) or bilirubin rise significantly above the patient's baseline.

Elderly Patients

No specific starting dose adjustment is required for the elderly; however, because older patients are more likely to have decreased renal function, monitoring of kidney function is vital to prevent drug accumulation and increased toxicity.

Injectable Form

• Administration: This form is administered only by a healthcare professional in a clinic or hospital setting.
• Subcutaneous Injection: If given under the skin, the injection sites should be rotated (thigh, abdomen, or upper arm). New injections should be given at least one inch from an old site and never into areas that are tender, bruised, red, or hard.
• Pre-medication: To prevent nausea and vomiting, your doctor will usually give you anti-nausea medication (antiemetics) 30 minutes before each dose.

Oral Form

• Consistency: Take the tablet at approximately the same time each day.
• Administration: Swallow tablets whole. Do not crush, chew, or break the tablets. If a tablet is broken or leaking, avoid touching the powder; if contact occurs, wash the area thoroughly with soap and water.
• Food: Can be taken with or without food.

• Injectable: If you miss an appointment for your injection, contact your oncology clinic immediately to reschedule. Maintaining the 7-day sequence is important for efficacy.
• Oral: If a dose is missed at the usual time, it should be taken as soon as possible on the same day. If more than 12 hours have passed, skip the missed dose and take the next dose at the scheduled time the following day. Do not take two doses at once.

Signs of overdose may include severe nausea, vomiting, diarrhea, or profound bone marrow suppression (extremely low blood counts). In the event of a suspected overdose, seek emergency medical attention. Treatment is supportive, as there is no specific antidote for Azacitidine.

> Important: Follow your healthcare provider's dosing instructions exactly. Do not adjust your dose or stop the medication without medical guidance.

Azacitidine affects the production of blood cells and the lining of the gastrointestinal tract, leading to several common side effects. Most patients will experience at least one of the following:

• Hematologic Effects: Anemia (low red blood cells), neutropenia (low white blood cells), and thrombocytopenia (low platelets) occur in the majority of patients. This can lead to fatigue, increased risk of infection, and easy bruising or bleeding.
• Gastrointestinal Distress: Nausea, vomiting, and diarrhea are very common, especially during the first two cycles of treatment. Constipation may also occur.
• Injection Site Reactions: For those receiving the subcutaneous form, redness, pain, bruising, or the formation of a small bump at the site of injection is frequent.
• General Systemic Symptoms: Fatigue, weakness (asthenia), fever, and loss of appetite (anorexia) are commonly reported.

• Dermatologic: Rash, itching (pruritus), or dry skin.
• Neurological: Dizziness, headache, or trouble sleeping (insomnia).
• Respiratory: Cough, sore throat, or shortness of breath (dyspnea).
• Musculoskeletal: Joint pain (arthralgia) or muscle aches (myalgia).

• Differentiation Syndrome: A serious condition where leukemia cells release chemicals into the blood, causing fever, respiratory distress, and fluid buildup.
• Interstitial Lung Disease: Inflammation of the lung tissue that can cause permanent scarring.
• Sweet's Syndrome: An acute inflammatory skin condition (febrile neutrophilic dermatosis) characterized by fever and painful skin lesions.

> Warning: Stop taking Azacitidine (if oral) and call your doctor immediately or seek emergency care if you experience any of the following:

• Signs of Infection: Fever over 100.4°F (38°C), chills, severe sore throat, or productive cough. This may indicate febrile neutropenia, which is a medical emergency.
• Unusual Bleeding: Nosebleeds, bleeding gums, blood in the stool (black/tarry), or heavy menstrual bleeding, indicating dangerously low platelets.
• Hepatotoxicity: Yellowing of the eyes or skin (jaundice), dark urine, or severe pain in the upper right side of the abdomen.
• Renal Failure: Significant decrease in urine output, swelling in the ankles or feet, or confusion.
• Severe Allergic Reaction: Hives, swelling of the face or throat, or difficulty breathing.

• Secondary Malignancies: As with many chemotherapy agents, there is a theoretical long-term risk of developing other types of cancer later in life, although the primary disease (MDS/AML) usually poses the more immediate threat.
• Organ Damage: Prolonged use may lead to cumulative effects on the kidneys or liver, requiring ongoing monitoring of lab values.

While Azacitidine does not currently carry a standard FDA "Black Box Warning" in the traditional boxed format, the prescribing information contains Critical Warnings regarding:

• Embryo-Fetal Toxicity: Azacitidine can cause fetal harm when administered to pregnant women. Both men and women of reproductive potential must use effective contraception during treatment.
• Substitution Warning: Oral Azacitidine (Onureg) cannot be substituted for injectable Azacitidine. The exposures and indications are different, and substitution could result in fatal toxicity or lack of efficacy.

Report any unusual symptoms to your healthcare provider immediately. Managing side effects early is key to continuing treatment successfully.

Azacitidine is a powerful medication that requires strict medical supervision. It is essential that patients adhere to all scheduled blood tests and follow-up appointments. The drug's primary action—suppressing the bone marrow—makes the patient vulnerable to life-threatening infections and bleeding episodes.

No FDA black box warnings are currently listed for Azacitidine; however, the FDA-approved labeling includes several 'Warnings and Precautions' that carry similar clinical weight, particularly regarding the non-interchangeability of the oral and injectable forms and the risks of myelosuppression.

• Myelosuppression: This is the most significant risk. Azacitidine frequently causes severe neutropenia (low white blood cells) and thrombocytopenia (low platelets). Complete Blood Counts (CBC) must be performed prior to each dosing cycle and as needed to monitor response and toxicity.
• Hepatotoxicity: In patients with pre-existing severe liver impairment, Azacitidine has been associated with liver failure and death. It should be used with extreme caution in patients with liver disease or liver metastases.
• Renal Toxicity: Renal abnormalities, ranging from elevated serum creatinine to renal failure and death, have been reported in patients treated with IV Azacitidine in combination with other chemotherapeutic agents. If renal function declines, the dose must be adjusted or withheld.
• Tumor Lysis Syndrome (TLS): Patients with a high tumor burden (many cancer cells) are at risk for TLS, where the rapid breakdown of cancer cells releases toxins into the blood. Healthcare providers may provide hydration and medications like allopurinol to prevent this.

Patients on Azacitidine require frequent laboratory monitoring to ensure safety:

• Complete Blood Count (CBC): Usually performed before each cycle and often mid-cycle to check for nadir (the lowest point of blood counts).
• Liver Function Tests (LFTs): Monitoring of AST, ALT, and bilirubin to detect early signs of liver stress.
• Renal Function Tests: Monitoring of Serum Creatinine and BUN (Blood Urea Nitrogen) to ensure the kidneys are clearing the drug and its metabolites effectively.
• Electrolytes: Monitoring for signs of Tumor Lysis Syndrome, including potassium, phosphate, and calcium levels.

Azacitidine may cause fatigue, dizziness, or weakness in some patients. If you experience these symptoms, avoid driving or operating heavy machinery until you know how the medication affects you.

There is no direct contraindication between alcohol and Azacitidine, but alcohol can worsen certain side effects like nausea and dehydration. Furthermore, alcohol can stress the liver, which is already a concern with Azacitidine. It is best to limit or avoid alcohol during treatment.

Stopping Azacitidine should only be done under the guidance of an oncologist. There is no 'withdrawal syndrome,' but stopping treatment prematurely may allow the underlying blood disorder or leukemia to progress rapidly. If the drug is stopped due to toxicity, it may be restarted at a lower dose once the patient recovers.

> Important: Discuss all your medical conditions, especially liver or kidney disease, with your healthcare provider before starting Azacitidine.

There are no specific drugs that are absolutely contraindicated (never to be used) with Azacitidine based on metabolic pathways alone. However, the use of Live Vaccines (such as the MMR, Rotavirus, or Yellow Fever vaccines) is generally contraindicated while the immune system is suppressed by Azacitidine, as this can lead to a severe, life-threatening infection from the vaccine itself.

• Other Myelosuppressive Agents: Taking Azacitidine with other chemotherapy drugs or medications that lower blood counts (like clozapine or certain immunosuppressants) can lead to profound and dangerous bone marrow suppression.
• Nephrotoxic Drugs: Medications that can damage the kidneys (such as NSAIDs like ibuprofen in high doses, certain antibiotics like aminoglycosides, or IV contrast dye) should be used cautiously, as Azacitidine is cleared by the kidneys and can itself cause renal stress.
• Hepatotoxic Drugs: Drugs that stress the liver (such as high-dose acetaminophen or certain anti-fungals) may increase the risk of liver injury when combined with Azacitidine.

• Warfarin and Anticoagulants: Because Azacitidine can lower platelet counts, the risk of bleeding is significantly increased if you are also taking blood thinners. Close monitoring of the INR (International Normalized Ratio) and signs of bleeding is required.

• Grapefruit: While Azacitidine is not primarily metabolized by the CYP3A4 enzyme (which grapefruit inhibits), it is generally advised to avoid large amounts of grapefruit juice during chemotherapy to maintain a stable metabolic environment.
• High-Fat Meals: For the oral form (Onureg), high-fat meals do not significantly change the total amount of drug absorbed, but consistency in how you take the medication (always with or always without food) is recommended.

• St. John's Wort: This herbal supplement can induce various metabolic pathways. While not a direct interaction with Azacitidine's primary metabolism, it can complicate the overall management of chemotherapy.
• Antioxidant Supplements: Some oncologists advise against high-dose antioxidant supplements (like Vitamin C or E) during active chemotherapy, as they may theoretically interfere with the oxidative stress mechanism by which some chemo drugs kill cancer cells.

Azacitidine does not typically interfere with the chemical analysis of lab tests, but its biological effects will profoundly alter the results of:

• CBC: Expect low white cells, red cells, and platelets.
• Liver/Kidney Panels: May show elevations in creatinine or liver enzymes due to drug toxicity.

For each major interaction, the primary concern is the pharmacodynamic effect—where two drugs have additive toxicities (like both lowering blood counts). The management strategy usually involves more frequent blood monitoring or adjusting the timing of the medications.

> Important: Tell your doctor about ALL medications, supplements, and herbal products you are taking, including over-the-counter pain relievers.

Azacitidine must NEVER be used in the following circumstances:

1. 1Known Hypersensitivity: Patients who have had a severe allergic reaction to Azacitidine or mannitol (an inactive ingredient in the injection) should not receive this drug. Anaphylaxis could occur.
2. 2Advanced Malignant Hepatic Tumors: Azacitidine is contraindicated in patients with advanced liver cancer. In clinical studies, patients with extensive liver metastasis experienced progressive hepatic coma and death when treated with Azacitidine. The drug's metabolism and potential for hepatotoxicity make it unsafe in this specific population.

Conditions requiring careful risk-benefit analysis include:

• Pre-existing Severe Renal Impairment: Since the drug is renally excreted, those with a GFR below 30 mL/min require extreme caution and significant dose modifications.
• Active Infection: Because Azacitidine lowers white blood cell counts, starting treatment during an active, uncontrolled infection (like sepsis or pneumonia) can be fatal. The infection should typically be treated first.
• Pregnancy: Azacitidine is a known teratogen (causes birth defects). It should only be used in pregnancy if the potential benefit to the mother outweighs the risk to the fetus, which is rare.

There is a potential for cross-sensitivity with other nucleoside analogues (like Decitabine). If a patient has had a severe reaction to Decitabine, healthcare providers will use Azacitidine with heightened caution, although they are chemically distinct enough that one does not always preclude the other.

> Important: Your healthcare provider will evaluate your complete medical history, including liver health and allergy history, before prescribing Azacitidine.

Azacitidine is classified by the FDA as having the potential for embryo-fetal toxicity. Based on its mechanism of action and animal studies, it can cause fetal harm, including birth defects and fetal death, when administered to a pregnant woman.

• Risk Summary: There are no adequate and well-controlled studies in pregnant women. In animal studies, Azacitidine was shown to be embryotoxic and teratogenic at doses lower than the human therapeutic dose.
• Contraception: Females of reproductive potential should use effective contraception during treatment and for at least 6 months after the last dose. Males with female partners of reproductive potential should use effective contraception during treatment and for 3 months after the last dose.

It is not known whether Azacitidine or its metabolites are excreted in human milk. Because many drugs are excreted in human milk and because of the potential for serious adverse reactions in nursing infants (including blood count suppression), women are advised not to breastfeed during treatment with Azacitidine and for one week after the final dose.

Azacitidine is approved for the treatment of juvenile myelomonocytic leukemia (JMML) in pediatric patients aged 1 month and older. Safety and effectiveness in other pediatric conditions or in infants younger than 1 month have not been established. In JMML trials, the side effect profile was generally similar to that seen in adults, though close monitoring of growth and development is always advised in pediatric oncology.

In clinical trials, a significant portion of patients treated with Azacitidine were 65 years of age or older. No overall differences in safety or effectiveness were observed between these patients and younger patients. However, elderly patients are more likely to have decreased renal function. Because Azacitidine is substantially excreted by the kidney, the risk of toxic reactions may be greater in patients with impaired renal function, necessitating careful dose selection and monitoring.

Patients with renal impairment (kidney disease) must be monitored closely for toxicity. Azacitidine and its metabolites are primarily cleared by the kidneys. While no specific starting dose adjustment is mandated for mild impairment, if a patient's serum creatinine increases significantly during treatment, the next cycle should be delayed or the dose reduced by 50%.

Azacitidine has not been formally studied in patients with pre-existing hepatic impairment (other than liver cancer). However, because the liver plays a role in the metabolism of the drug, and because the drug is potentially hepatotoxic, patients with liver disease should be monitored frequently for signs of worsening liver function.

> Important: Special populations require individualized medical assessment and more frequent laboratory monitoring.

Azacitidine is a pyrimidine nucleoside analogue of cytidine. Its primary molecular mechanism involves the inhibition of DNA methyltransferases (DNMTs). Once Azacitidine is phosphorylated into its active form (azacitidine triphosphate), it is incorporated into DNA and RNA.

In DNA, Azacitidine functions as a 'suicide substrate' for DNMTs. By covalently binding to these enzymes, it prevents them from adding methyl groups to the DNA. This results in DNA hypomethylation, which can re-activate tumor suppressor genes that were previously silenced by hypermethylation. In RNA, Azacitidine incorporation leads to the disruption of protein synthesis, which is directly cytotoxic to abnormal hematopoietic cells in the bone marrow.

The pharmacodynamic effect of Azacitidine is measured by the reduction in DNA methylation levels in peripheral blood or bone marrow cells. This effect is dose-dependent but also depends on the cells being in the S-phase (DNA synthesis phase) of the cell cycle. The onset of clinical effect (improvement in blood counts) is usually slow, often requiring 4 to 6 cycles of treatment. Tolerance to the drug's myelosuppressive effects does not typically develop; rather, toxicities may be cumulative.

| Parameter | Value |

|---|---|

| Bioavailability | ~89% (Subcutaneous), ~11% (Oral) |

| Protein Binding | < 1% |

| Half-life | ~41 minutes (Injectable) |

| Tmax | 30 minutes (Subcutaneous), 1 hour (Oral) |

| Metabolism | Spontaneous hydrolysis; Deamination by cytidine deaminase |

| Excretion | Renal 50-85%, Fecal < 1% |

• Molecular Formula: C8H12N4O5
• Molecular Weight: 244.20 g/mol
• Solubility: Soluble in water, dimethylsulfoxide (DMSO), and ethanol. It is chemically unstable in aqueous solution and must be administered shortly after reconstitution.
• Structure: It consists of a triazine ring attached to a ribofuranose sugar.

Azacitidine is a nucleoside metabolic inhibitor and a hypomethylating agent. It is closely related to Decitabine (Dacogen), which is another hypomethylating agent used for MDS. Unlike Decitabine, which is only incorporated into DNA, Azacitidine is incorporated into both DNA and RNA.