Article
Co-prescription of QT-interval prolonging drugs: an analysis in a large cohort of geriatric patients
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Authors
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Simone Schächtele
- Institute of Experimental and Clinical Pharmacology and Toxicology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
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Thomas Tümena
- Geriatrics in Bavaria-Database (Geriatrie in Bayern-Datenbank, GIB-Dat), Nürnberg, Germany
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Karl-Günther Gaßmann
- Geriatrics Center Erlangen, Waldkrankenhaus St. Marien gGmbH, Erlangen, Germany
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Martin F. Fromm
- Institute of Experimental and Clinical Pharmacology and Toxicology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
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Renke Maas
- Institute of Experimental and Clinical Pharmacology and Toxicology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| Published: | September 24, 2015 |
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Outline
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Aim: To assess the individual burden of QT-interval prolonging drugs (QT-drugs) in geriatric patients and to identify the most frequent and risky combinations of QT-drugs.
Methods: In this retrospective cohort study (co)-prescriptions of QT-drugs in the discharge medication of geriatric patients between July 2009 and June 2013 from the Geriatrics in Bavaria–Database (GiB-DAT) were investigated. QT-drugs were classified according to a publicly available reference site (Crediblemeds®) and in addition according to the German prescribing information (SmPC) as ALL-QT-drugs (any QT-risk), High-risk-QT-drugs (corresponding to QT-drugs with known risk of Torsades de Pointes according to Crediblemeds®) or as SmPC-high-risk-QT-drugs (with contraindicated co-prescription together with other QT-drugs according to German SmPC).
Results: We assessed the medication of 130.434 geriatric patients (mean age 81 years, 67 % women), prescribed a median 8 of drugs. Of these, 76.594 patients (58.7 %) received at least one QT-drug. Co-prescriptions of two or more QT-drugs were observed in 28.768 (22.1 %) patients.
Particularly risky co-prescriptions of two or more QT-drugs involving at least one QT-drug classified as High-risk-QT-drug or as SmPC-high-risk-QT-drug occurred in 55.8 % (N=12.619) and 54.2 % (N=10.512) of these patients, respectively. The most commonly involved drugs were citalopram, escitalopram, amitriptyline, amiodarone and domperidone. Analysis of SmPC-high-risk-QT-drugs allowed the identification of an additional 15 % (N=3.999) patients taking a risky combination that was not covered by the Crediblemeds® classification. Only 20 drug-drug combinations accounted for more than 90 % of the potentially most dangerous co-prescriptions including at least one QT-drug with higher risk.
Conclusion: In a geriatric study population co-prescriptions of two and more QT-drugs were common. A considerable proportion of QT-drugs with higher risk only could be detected by using more than one classification-system. International classifications may benefit from local adaptation of the top 20 problematic drug-drug combinations and aid physicians in identifying patients at risk in the daily clinical practice.
