Cytoxan

Cytoxan (cyclophosphamide) is a chemotherapy drug most commonly used in the treatment of breast cancer.

How does it work?

Cyclophosphamide is an ntitumor agent alkylating action. It has a cytostatic and immunosuppressive effect. The antitumor effect is realized directly in the tumor cells, where cyclophosphamide is biotransformed under the action of phosphatases with the formation of an active metabolite with an alkylating effect.

Indications for use

• Ovarian cancer, breast cancer, lung cancer, lymphogranulomatosis, non-Hodgkin’s lymphoma, lymphosarcoma, reticulosarcoma, osteogenic sarcoma, multiple myeloma, chronic lymphocytic leukemia, acute lymphoblastic leukemia, Wilms tumor, Ewing’s sarcoma, testicular seminoma;
• Prevention of transplant rejection reaction;
• Rheumatoid arthritis, multiple sclerosis, systemic lupus erythematosus, nephrotic syndrome (as an immunosuppressant).

Contraindications

Do not take Cytoxan if you have any of the following conditions:

• allergies to the active component;
• allergies to auxiliary components;
• pregnancy, breastfeeding;
• severe inhibition of bone marrow function;
• severe renal impairment;
• leukopenia;
• thrombocytopenia;
• severe anemia;
• severe cachexia;
• terminal stages of cancer.

Pregnancy and breastfeeding

Cytoxan is contraindicated for use in pregnancy. If it is necessary to use these pills during lactation, breastfeeding should be interrupted.

Women of childbearing age should use reliable methods of contraception during therapy.

In experimental studies, the teratogenic and embryotoxic effect of cyclophosphamide was established.

Dosage

The dosage of the drug is determined individually, depending on the indications and stage of the disease, the state of the hematopoietic system, anti-tumor therapy regimen.

Cytoxan tablets should be taken whole. Never cut, crush, or chew them.

Side effects

• Digestive disorders: dry mouth, anorexia, stomatitis, nausea, stomach pain, vomiting, diarrhea, gastrointestinal bleeding, toxic hepatitis, hemorrhagic colitis, jaundice;
• Neurological disorders: asthenia, headache, confusion, dizziness, visual impairment;
• Cardiovascular disorders: myelosuppression, thrombocytopenia, leukopenia, agranulocytosis, anemia, bleeding/hemorrhage, cardiotoxicity, flushing, heart failure, hemorrhagic myopericarditis, palpitations, pericarditis;
• Respiratory disorders: shortness of breath, interstitial pneumosclerosis, pneumonitis;
• Genitourinary disorders: hemorrhagic cystitis, bladder fibrosis, urethritis, atypia of bladder cells, dysuria (painful, difficult or rapid urination), hematuria, edema of the lower extremities, hyperuricemia, nephropathy, hyperuricosuria, amenorrhea, necrosis, necrosis, necrosis, necrosis, necrosis, necrosis, necrosis, necrosis;
• Dermatological disorders: hyperpigmentation (nails, palms), alopecia, intradermal hemorrhages, rash, facial redness, urticaria, swelling, itching, hyperemia;
• Other: pain (pain in the joints, back, bones), anaphylactoid reactions, fever, syndrome of inadequate secretion of ADH, chills, the development of infections, myxedema, increased activity of transaminases in the blood, hyperglycemia.

Overdose

Symptoms: nausea, severe bone marrow depression, vomiting, fever, multiple organ failure, dilated cardiomyopathy syndrome, hemorrhagic cystitis.

Treatment: hospitalization, symptomatic therapy, monitoring of vital functions, if necessary – the introduction of blood stimulants, transfusion of blood components, the use of broad-spectrum antibiotics.

Drug interaction

• Cyclophosphamide can enhance the effect of hypoglycemic drugs;
• The simultaneous use of cyclophosphamide with allopurinol can lead to increased myelotoxicity;
• The simultaneous use of cyclophosphamide with indirect anticoagulants can change anticoagulant activity (as a rule, cyclophosphamide reduces the synthesis of coagulation factors in the liver and disrupts the formation of platelets);
• The simultaneous use of cyclophosphamide with cytarabine, daunorubicin or doxorubicin can increase the cardiotoxic effect;
• The simultaneous use of cyclophosphamide with immunosuppressants increases the risk of infections and secondary tumors;
• The simultaneous use of cyclophosphamide with lovastatin increases the risk of acute skeletal muscle necrosis and acute renal failure;
• Medicines that are inducers of microsomal enzymes cause an increased formation of active cyclophosphamide metabolites, which leads to an increase in its action.

Precautions

It is not recommended to use Cytoxan in patients with chickenpox (including recently transferred or after contact with patients), with herpes zoster, and other acute infectious diseases.

The pills are used with caution in patients with a history of gout or nephrolithiasis, as well as after adrenalectomy (correction of hormone replacement therapy and doses of cyclophosphamide is necessary).

The drug is used with caution in patients with bone marrow infiltration by tumor cells, as well as in patients who received antitumor chemotherapy or radiation therapy.

In the process of treatment, it is necessary to monitor the peripheral blood picture: ​​during the main course – 2 times/week; with maintenance treatment – 1 time/week. With a decrease in the number of leukocytes to 2500/μl and platelets to 100 000/μl, treatment should be stopped.

In the process of treatment, it is necessary to monitor the activity of hepatic transaminases and LDH, the level of bilirubin, the concentration of uric acid in the blood plasma, urine output and specific gravity of the urine. It is also necessary to pass tests to detect microhematuria.

When using cyclophosphamide in higher doses in order to prevent hemorrhagic cystitis, it is recommended to prescribe mesna.

In experimental studies, the carcinogenic and mutagenic effects of cyclophosphamide have been established.