Cyclophosphamide is biotransformed to active metabolites inthe liver by a microsomal oxidase system with mixed functionalities. Themetabolites affect the growth of malignant cells and cross-link the DNA of thetumor cells.
Hematologic side effects of cyclophosphamide includemyelosuppression, leucopenia, anemia, are rare cases of methemoglobinemia andsometimes aplastic anemia. Some women may experience more frequently thromboembolic events. Gastrointestinal side effects are much more common andthey include emesis of various severities, anorexia, pain, diarrhea, abdominaldiscomfort and quiet often vomiting and nausea. There have been some reports ofoccurrences of jaundice, oral mucosal ulceration and hemorrhagic colitis. Dermatologicside effects of cyclophosphamide quite commonly include alopecia and in rarecases nail and skin pigmentation changes may also occur. These have even been in some cases of toxic epidermal necrolysis and Stevens-Johnson syndrome as well.The medication affects the scalp and it causes hair loss, follicle damage andloss of pubic hair.
In most cases, genitourinary side effects of cyclophosphamideinclude hemorrhagic cystits. Other genitourinary side effects may or may notinclude dysuria, renal tubular necrosis, urgency, nocturia, irritative voiding,urinary frequency, incontinence, bladder fibrosis, hemorrhagic urethritis andnonhemorrhagic cystitis. Cyclophosphamide is also known for causing lunginjuries in some cases. It induces pulmonary toxicity and it can be furtherexacerbated by other medications and therapies. Other respiratory side effectsmay include dyspnea, pulmonary edema, cough fever, abnormal lung sounds,pneumonitis and interstitial pulmonary fibrosis.
Cyclophosphamide can also be the cause of acute cardiactoxicity and sometimes even lead to congestive heart failure. The risk ofcardiovascular side effects can be decreased by splitting one’s daily dose intotwo infusions. The medication can also affect the endocrine system. It canactually interfere with spermatogenesis and oogenesis. It may induce amenorrheain women and azoospermia in men.
It is also known for causing sterility andhyponatremia in certain cases. Some studies have associated it with ovarianfibrosis and testicular atrophy. Hypersensitivity side effects of cyclophosphamideinclude delayed-type reactions, anaphylaxis, cutaneous vasculitis and evendeath. Oncologic side effects of this medication includes secondary neoplasiathat mostly affects the patients with underlying lymphoproliferative andmyeloproliferative disorders and malignancies. Cyclophosphamide is sometimesused with certain other antineoplastic agents such as carboplatin and cisplatinand this combination sometimes triggers conditions known as peripheralneuropathy and ototoxicity. Other side effects that affect the nervous systemincludes dizziness, headaches, asthenia and depression.
This medication can also cause rheumatic syndromes andmusculoskeletal pains. Sometimes even arthralgias and myalgias can occur.