Cimetidine Carmustine

Studies in animals suggest that cimetidine impairs the clearance of carmustine. Cimetidine has also increased the levels or toxicity of some oth-... 

CARMUSTINE H2 RECEPTOR BLOCKERS -CIMETIDINE t adverse effects of alkylating agent, e.g. myelosuppression Additive toxicity Monitor more closely monitor FBC regularly... 

CIMETIDINE BUSULFAN, CARMUSTINE, CHLORAMBUCIL CYCLOPHOSPHAMIDE, ESTRAMUSTINE, IFOS-FAMIDE, LOMUSTINE, THIOTEPA, TREOSULFAN T adverse effects of cytotoxic, e.g. myelosuppression Additive toxicity. Possible minor inhibition of cyclophosphamide metabolism via CYP2C9 Monitor more closely monitor FBC regularly. Avoid co-administration of cimetidine with cyclophosphamide... 

Bone marrow suppression by carmustine may be enhanced by cimetidine (23,24). 

Selker RG, Moore P, Lodolce D. Bone-marrow depression with cimetidine plus carmustine. N Engl J Med 1978 299(15) 834. 

Volkin RL, Shadduck RK, Winkelstein A, Zeigler ZR, Selker RG. Potentiation of carmustine—cranial irradiation-induced myelosuppression by cimetidine. Arch Intern Med 1982 142(2) 243-5. 

The bone marrow depressant effects of carmustine and lomustine are possibly increased by cimetidine. 

Nine patients treated with carmustine 80 mg/m daily for 3 days, cimetidine 300 mg four times daily for 1 to 4 weeks, steroids, and cranial irradiation over 6 weeks, demonstrated marked leucopenia during the first cycle. Bone marrow aspirates confirmed the marked decrease in granulocytic elements in 2 patients. In comparison, 31 patients treated similarly, but without cimetidine, had no significant white cell depression. Neutropenia was found in a man taking regular cimetidine, phenytoin, phenobarbital, and dexamethasone, 53 days after he was given lomustine 120 mg, and 16 days after he was given lomustine 160 mg. The cimetidine was discontinued and the neutropenia rapidly reversed within 14 days. The neutrophil nadir from the lomustine 160 mg dose occurred after a further 16 to 19 days and was much less severe. ... 

Information appears to be limited to the reports cited, but it seems to be an established reaction. Patients given both drugs should be elosely monitored for changes in blood cell counts. Because of its immunomodulatory effects, cimetidine has been used as an adjunct to carmustine in the treatment of malignant melanoma, but this did not improve outcomes. ... 

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