What it's for (Indications)
- Cyclophosphamide is a widely utilized alkylating agent with significant antineoplastic and immunosuppressive properties.
- In oncology, its indications span a broad spectrum of malignancies, including Hodgkin's disease, non-Hodgkin's lymphoma, multiple myeloma, acute and chronic leukemias (lymphocytic and myeloid), mycosis fungoides, neuroblastoma, retinoblastoma, ovarian adenocarcinoma, and breast cancer.
- It is often employed in combination chemotherapy regimens due to its broad cytotoxic spectrum.
- Beyond cancer therapy, cyclophosphamide is indispensable in managing severe autoimmune and inflammatory conditions resistant to less aggressive treatments.
- This includes severe active rheumatoid arthritis, systemic lupus erythematosus (particularly lupus nephritis), granulomatosis with polyangiitis (Wegener's granulomatosis), microscopic polyangiitis, and certain cases of nephrotic syndrome.
- Its efficacy stems from its potent cytotoxic and immunosuppressive actions, making it a critical component in various therapeutic regimens when other treatments have failed or are insufficient.
Dosage Information
| Type | Guideline |
|---|---|
| Standard | The dosage of cyclophosphamide is highly individualized, contingent upon the specific indication, patient's body surface area (BSA) or weight, renal and hepatic function, hematologic status, and whether it is administered as monotherapy or part of a combination regimen. It can be given orally or intravenously. Typical oncologic dosages range from daily low doses (e.g., 50-200 mg/day orally) to intermittent high doses (e.g., 500-1500 mg/m² intravenously every 3-4 weeks), depending on the tumor type and treatment protocol. For immunosuppression, regimens might involve lower daily oral doses or pulse intravenous therapy, such as 500-1000 mg/m² monthly. Meticulous dose adjustments are crucial in patients with impaired bone marrow reserve, renal insufficiency (creatinine clearance < 60 mL/min), or hepatic dysfunction. Adequate hydration and the concomitant administration of mesna (2-mercaptoethanesulfonate sodium) are often mandatory, especially with higher intravenous doses, to mitigate the risk of hemorrhagic cystitis. Close monitoring of blood counts and urinalysis is essential throughout the entire course of treatment to guide dose modifications and manage toxicities. |
Safety & Warnings
Common Side Effects
- Cyclophosphamide is associated with a wide array of side effects, reflecting its systemic cytotoxic activity.
- Myelosuppression, leading to leukopenia (particularly neutropenia), thrombocytopenia, and anemia, is a major dose-limiting toxicity, significantly increasing the risk of life-threatening infections and hemorrhagic events.
- Gastrointestinal toxicities are common and can be severe, including profound nausea and vomiting, mucositis (stomatitis), and diarrhea, often necessitating aggressive antiemetic prophylaxis and supportive care.
- Alopecia (hair loss) is frequent and typically reversible upon discontinuation.
- Urologic toxicity, primarily hemorrhagic cystitis, results from acrolein metabolites accumulating in the bladder; this is preventable with adequate hydration and mesna.
- Cardiotoxicity, ranging from asymptomatic ECG changes to acute congestive heart failure and myocarditis, can occur, particularly with very high cumulative doses or in patients with pre-existing cardiac disease.
- Pulmonary fibrosis, interstitial pneumonitis, and secondary malignancies (e.
- g.
- , myelodysplastic syndrome, acute myeloid leukemia, bladder cancer) are severe long-term risks.
- Gonadal dysfunction, leading to permanent infertility in both sexes, is a significant concern for reproductive-aged patients.
- Other potential effects include SIADH (syndrome of inappropriate antidiuretic hormone secretion), hepatic dysfunction, hypersensitivity reactions, and increased susceptibility to various infections due to profound immunosuppression.
Serious Warnings
- Black Box Warning: **WARNING: MYELOSUPPRESSION, IMMUNOSUPPRESSION, INFECTIONS, HEMORRHAGIC CYSTITIS, CARDIOTOXICITY, SECONDARY MALIGNANCIES, GONADAL SUPPRESSION, AND EMBRYO-FETAL TOXICITY** * **Myelosuppression and Immunosuppression:** Cyclophosphamide can cause severe, dose-dependent myelosuppression (leukopenia, neutropenia, thrombocytopenia, anemia) which can be life-threatening and lead to fatal infections and sepsis. Patients must be monitored closely for signs of infection, and frequent, complete hematologic assessments are mandatory throughout and after treatment. Profound immunosuppression increases the risk of opportunistic infections and reactivation of latent viruses. * **Hemorrhagic Cystitis:** Hemorrhagic cystitis, a severe urotoxic effect, can lead to bladder fibrosis, hemorrhage, and an increased risk of bladder cancer. Adequate hydration and the use of mesna are critical for prevention, especially with intravenous administration and high doses. * **Cardiotoxicity:** Acute myocardial necrosis, pericarditis, myocarditis, and congestive heart failure can occur, particularly with high doses or in patients with pre-existing cardiac disease. This can be fatal. * **Secondary Malignancies:** Cyclophosphamide is carcinogenic and has been associated with an increased risk of secondary malignancies, including myelodysplastic syndrome, acute myeloid leukemia, and bladder cancer, often occurring after prolonged exposure. * **Gonadal Suppression:** Cyclophosphamide can cause irreversible gonadal suppression leading to permanent infertility in both male and female patients, which may be dose-dependent. * **Embryo-Fetal Toxicity:** Cyclophosphamide is teratogenic and embryotoxic. It can cause fetal harm, including severe malformations and fetal death, when administered to a pregnant woman. Women of childbearing potential should be advised to avoid pregnancy, and effective contraception must be used during treatment and for a prolonged period after discontinuation.
- Cyclophosphamide therapy demands rigorous monitoring and vigilance due to its profound systemic effects.
- Severe myelosuppression is a hallmark toxicity, necessitating frequent complete blood counts with differential to detect leukopenia (especially neutropenia) and thrombocytopenia, guiding potential dose reductions or treatment delays to prevent life-threatening infections and hemorrhage.
- Hemorrhagic cystitis, a dose-dependent toxicity, requires aggressive hydration and prophylactic mesna administration, particularly with intravenous dosing, to prevent bladder injury and potential long-term bladder carcinogenicity.
- Cardiotoxicity, encompassing acute myocardial necrosis, myocarditis, and chronic cardiomyopathy, is a serious risk, especially with high doses or in patients with pre-existing cardiac conditions; cardiac function should be assessed.
- Pulmonary toxicity, including interstitial pneumonitis and fibrosis, may lead to irreversible lung damage and requires prompt investigation of respiratory symptoms.
- The risk of developing secondary malignancies, including bladder cancer and acute leukemias, significantly increases with cumulative cyclophosphamide exposure and duration of therapy.
- Gonadal suppression, often leading to permanent infertility in both males and females, should be discussed thoroughly with patients, especially those of reproductive age, and fertility preservation options considered.
- Cyclophosphamide is teratogenic and embryotoxic, posing severe risks during pregnancy, and is excreted into breast milk, making it contraindicated in both conditions.
- Profound immunosuppression increases susceptibility to various infections, including opportunistic pathogens, requiring careful patient monitoring and appropriate prophylactic measures.
How it Works (Mechanism of Action)
Cyclophosphamide functions as a nitrogen mustard alkylating agent, a prodrug requiring metabolic activation primarily by cytochrome P450 enzymes (CYP2B6, CYP2C19, CYP3A4/5) located in the liver. This biotransformation process generates 4-hydroxycyclophosphamide, which exists in equilibrium with its tautomer, aldophosphamide. Aldophosphamide is then transported to target cells where it spontaneously cleaves into two key active metabolites: phosphoramide mustard and acrolein. Phosphoramide mustard is the principal cytotoxic agent. It exerts its antineoplastic effects by forming covalent bonds (alkylating) with DNA, primarily at the N-7 position of guanine residues. This alkylation leads to the formation of interstrand and intrastrand DNA cross-links, as well as DNA adducts. These DNA modifications interfere with crucial cellular processes such as DNA replication, RNA transcription, and subsequent protein synthesis, ultimately triggering cell cycle arrest and inducing apoptosis (programmed cell death) in rapidly dividing cells, including malignant cells and certain immune cells. Cyclophosphamide is considered a non-cell cycle specific agent, meaning its effects are not restricted to a particular phase of the cell cycle. Acrolein, while not directly cytotoxic in terms of tumor kill, is responsible for the significant urotoxic side effects, notably hemorrhagic cystitis, due to its irritant effects on the bladder epithelium.
Commercial Brands (Alternatives)
No other brands found for this formula.