Antimitotic antimetabolite agent. This hydrosoluble pyrimidic nucleoside-resembling cytidin inhibits desoxycytidin synthesis by a competitive mechanism. It is used in the treatment of acute leukemia and some solid tumors.
Incidence
Type I reactions: uncommon.
Cytarabine syndrome: up to 21% of treated patients in some reports.
Toxic conjunctivitis: uncommon.
Neutrophilic eccrine hidradenitis: uncommon.
Palmar-plantar syndrome: rare.
Clinical manifestations
Type I reactions: dyspnea, chest pain, fever, angioedema, urticaria, hypotension.
Cytarabine syndrome: fever, rigors, diaphoresis, myalgia, arthralgia, maculopapular rash, hypotension, conjunctivitis.
Palmar-Plantar erythema: +/- generalized erythematous maculopapular rashes.
Neutrophilic eccrine hidradenitis: tender, erythematous, indurated lesions (trunk + upper extremities).
Diagnostic methods
Type I reactions.
Cutaneous testing.
Prick-tests are negative.
A few cases of positive intradermal skin-tests at a concentration of 4 µg/ml.
Presence of specific IgE antibodies: in some patients with anaphylactic shock.
Specific histamine release.
Mechanisms
Type I reactions: IgE-mediated hypersensitivity is suggested by immediately positive intradermal skin tests, detection of IgE antibodies and passive cutaneous anaphylaxis.
Cytarabine syndrome, toxic conjunctivitis, neutrophilic eccrine hidradenitis: direct toxicity is likely.
Management
Type I reactions.
Desensitization.
Adults (1 case): starting with 10 ml of 0,002% cytarabine up to 200 mg of cytarabine in 500 cc of saline.
Children (1 case): 200 µg to 45 mg in 13 hours.
Other reactions.
Pretreatment with corticosteroids is sometimes helpful.