Effect of omeprazole on the pharmacokinetics and toxicities of irinotecan in cancer patients: A prospective cross-over drug–drug interaction study

Department of Medical Oncology, Erasmus MC – Daniel den Hoed Cancer Center, University Medical Center, Rotterdam, The Netherlands.
European journal of cancer (Oxford, England: 1990) (Impact Factor: 5.42). 04/2011; 47(6):831-8. DOI: 10.1016/j.ejca.2010.11.030
Source: PubMed

ABSTRACT Omeprazole is one of the most prescribed medications worldwide and within the class of proton pump inhibitors, it is most frequently associated with drug interactions. In vitro studies have shown that omeprazole can alter the function of metabolic enzymes and transporters that are involved in the metabolism of irinotecan, such as uridine diphosphate glucuronosyltransferase subfamily 1A1 (UGT1A1), cytochrome P-450 enzymes subfamily 3A (CYP3A) and ATP-binding cassette drug-transporter G2 (ABCG2). In this open-label cross-over study we investigated the effects of omeprazole on the pharmacokinetics and toxicities of irinotecan.
Fourteen patients were treated with single agent irinotecan (600mg i.v., 90min) followed 3weeks later by a second cycle with concurrent use of omeprazole 40mg once daily, which was started 2weeks prior to the second cycle. Plasma samples were obtained up to 55h after infusion and analysed for irinotecan and its metabolites 7-ethyl-10-hydroxycampothecin (SN-38), SN-38-glucuronide (SN-38G), 7-ethyl-10-[4-(1-piperidino)-1-amino]-carbonyloxycamptothecin (NPC) and 7-ethyl-10-[4-N-(5-aminopentanoic acid)-1-piperidino]-carbonyloxycamptothecin (APC) by high-performance liquid chromatography (HPLC). Non-compartmental modelling was performed. Toxicities were monitored during both cycles. Paired statistical tests were performed with SPSS.
The exposure to irinotecan and its metabolites was not significantly different between both cycles. Neither were there significant differences in the absolute nadir and percentage decrease of WBC and ANC, nor on the incidence and severity of neutropenia, febrile neutropenia, diarrhoea, nausea and vomiting when irinotecan was combined with omeprazole.
Omeprazole 40mg did not alter the pharmacokinetics and toxicities of irinotecan. This widely used drug can, therefore, be safely administered during a 3-weekly single agent irinotecan schedule.

Download full-text


Available from: Erik A C Wiemer, Sep 28, 2015
36 Reads
  • Clinical gastroenterology and hepatology: the official clinical practice journal of the American Gastroenterological Association 06/2011; 9(10):e106-7. DOI:10.1016/j.cgh.2011.06.001 · 7.90 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: It has been shown that anti-cancer drug induces secretion of serotonin (5-HT) from small intestine which activates serotonin type 3 (5-HT(3)) receptor to cause nausea and vomiting. In general, antagonist for 5-HT(3) receptor is used as anti-emetics during chemotherapy. However, we found that anti-cancer drug irinotecan itself inhibits 5-HT-gated current through the homomeric 5-HT(3A) and heteromeric 5-HT(3AB) receptor in a concentration-dependent manner. The inhibitory effect of irinotecan on 5-HT(3A) receptor was more potent than that on 5-HT(3AB) receptor. On the other hand, SN-38, a metabolite of irinotecan, had no effect on the responsiveness. Our findings suggest that irinotecan itself could have anti-emetic activities through inhibition of the 5-HT(3A) and 5-HT(3AB) receptor.
    Biochemical and Biophysical Research Communications 10/2011; 415(2):416-20. DOI:10.1016/j.bbrc.2011.10.084 · 2.30 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: St John's wort (SJW), a herbal antidepressant, is commonly used by cancer patients, and its component hyperforin is a known inducer of the cytochrome P450 (CYP) isoenzyme 3A4. Here, the potential pharmacokinetic interaction between SJW and the sensitive CYP3A4 substrate docetaxel was investigated. In ten evaluable cancer patients, the pharmacokinetics of docetaxel (135 mg administered intravenously over 60 min) were compared before and after 14 days of supplementation with SJW (300 mg extract [Hyperiplant(®)] three times daily). SJW supplementation resulted in a statistically significant decrease in the mean area under the docetaxel plasma concentration-time curve extrapolated to infinity (AUC∞) from 3,035 ± 756 to 2,682 ± 717 ng · h/mL (P = 0.045). Furthermore, docetaxel clearance significantly increased from 47.2 to 53.7 L/h (P = 0.045) after SJW intake. The maximum plasma concentration and elimination half-life of docetaxel were (non-significantly) decreased after SJW supplementation. In addition, the incidence of docetaxel-related toxicities was lower after SJW supplementation. These results suggest that concomitant use of docetaxel and the applied SJW product should be avoided to prevent potential undertreatment of cancer patients.
    Clinical Pharmacokinetics 09/2013; 53(1). DOI:10.1007/s40262-013-0102-5 · 5.05 Impact Factor
Show more