Toxic interaction between fluvoxamine and sustained release theophylline in an 11-year-old boy.
An 11-year-old boy with asthma had been receiving a controlled release theophylline preparation. He was prescribed fluvoxamine for a depressive disorder and within a week complained of severe headaches, tiredness and vomiting. His serum theophylline concentration had increased from 14.2 mg/L (shortly before fluvoxamine was started) to 27.4 mg/L. Fluvoxamine was withdrawn and theophylline concentrations decreased. Clomipramine was substituted for fluvoxamine with no further problems, and a later theophylline concentration was 13.7 mg/L. Competitive inhibition of hepatic microsomal enzymes by fluvoxamine may have been responsible for the elevated theophylline concentrations and toxicity observed in this case.
Sperber
A D
AD
Institute of Gastroenterology, Soroka Medical Center, Beer-Sheva, Israel.
D000284:Administration, Oral; D002648:Child; D003692:Delayed-Action Preparations; D004347:Drug Interactions; D016666:Fluvoxamine / Q000008:administration & dosage / Q000009:adverse effects*; D006801:Humans; D008297:Male; D013806:Theophylline / Q000008:administration & dosage / Q000009:adverse effects* / Q000097:blood
D003692:Delayed-Action Preparations; D013806:Theophylline; D016666:Fluvoxamine