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Drug Interactions Between Anti‐Epileptics and Chemotherapeutic Drugs: Value of a Pre‐Treatment Pharmaceutical Review
Author(s) -
Mellor James D,
Jayasinghe Charini
Publication year - 2011
Publication title -
journal of pharmacy practice and research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.222
H-Index - 22
eISSN - 2055-2335
pISSN - 1445-937X
DOI - 10.1002/j.2055-2335.2011.tb00065.x
Subject(s) - medicine , irinotecan , chemotherapy , carbamazepine , pharmacology , drug , ifosfamide , vincristine , drug interaction , doxorubicin , etoposide , oncology , cyclophosphamide , regimen , epilepsy , cancer , psychiatry , colorectal cancer
Background Many cancer patients take medications for preexisting comorbidities that are unrelated to their malignancy. Eliciting an accurate medication history prior to cancer chemotherapy is important to ensure that any drug‐drug interactions are detected, assessed and avoided. Aim To report a potential case of an interaction between antiepileptics and chemotherapeutic drugs. Clinical details A 24‐year‐old female with rapidly progressing metastatic rhabdomyosarcoma of the right maxillary sinus was treated with the Children's Oncology Group ARST0431 protocol for high‐risk rhabdomyosarcoma. This intensive regimen combines radiation therapy with 7 chemotherapeutic drugs: vincristine, irinotecan, cyclophosphamide, ifosfamide, doxorubicin, etoposide and actinomycin‐D. During routine pre‐treatment medication reconciliation, the pharmacist identified that the patient was also taking carbamazepine, a potent inducer of cytochrome P450 (CYP) enzymes, for left‐sided focal epilepsy. Outcome There was potential for clinically relevant drug interactions because CYP enzymes were responsible for metabolising some of the chemotherapy drugs planned for her treatment. The pharmacist's intervention resulted in carbamazepine switched to levetiracetam, a non‐enzyme inducing antiepileptic, and avoiding the potential interaction. Conclusion This case highlights the value of clinical pharmacists undertaking medication reconciliation prior to the start of cancer chemotherapy.