High-dose tamoxifen in treatment of brain tumors: interaction with antiepileptic drugs.
The incidence of seizures related to primary brain tumors is 20-80%. High-dose tamoxifen was recently reported as a novel treatment for patients with malignant gliomas who have failed standard therapies. Tamoxifen inhibits protein kinase C (PKC) in vitro and thus may regulate glioma cell growth by modulating intracellular signal transduction. We report a patient with a recurrent supratentorial pilocytic astrocytoma who had an untoward interaction between high-dose tamoxifen therapy and phenytoin (PHT), drugs that share a common enzyme for metabolism, therefore emphasizing the need to monitor concomitant antiepileptic drug (AED) levels when high-dose tamoxifen therapy is instituted.
Rabinowicz
A L
AL
USC Epilepsy Center, University of Southern California School of Medicine, Los Angeles, USA.
Hinton
D R
DR
Dyck
P
P
Couldwell
W T
WT
D000328:Adult; D001932:Brain Neoplasms / Q000188:drug therapy* / Q000201:enzymology; D002455:Cell Division / Q000187:drug effects; D004347:Drug Interactions; D005910:Glioma / Q000188:drug therapy* / Q000201:enzymology; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D010672:Phenytoin / Q000009:adverse effects / Q000494:pharmacology*; D011493:Protein Kinase C / Q000037:antagonists & inhibitors; D015398:Signal Transduction / Q000187:drug effects; D013629:Tamoxifen / Q000494:pharmacology / Q000627:therapeutic use*
D013629:Tamoxifen; D010672:Phenytoin; D011493:Protein Kinase C