Editing Quinine (section)

==Contraindications==
Because of the narrow difference between its therapeutic and toxic effects, quinine is a common cause of drug-induced disorders, including [[thrombocytopenia]] and [[thrombotic microangiopathy]].<ref name="liles">{{cite journal | vauthors = Liles NW, Page EE, Liles AL, Vesely SK, Raskob GE, George JN | title = Diversity and severity of adverse reactions to quinine: A systematic review | journal = American Journal of Hematology | volume = 91 | issue = 5 | pages = 461–466 | date = May 2016 | pmid = 26822544 | doi = 10.1002/ajh.24314 | doi-access = free }}</ref> Even from minor levels occurring in common beverages, quinine can have severe [[adverse event|adverse effects]] involving multiple organ systems, among which are [[immune system]] effects and [[fever]], [[hypotension]], [[hemolytic anemia]], [[acute kidney injury]], liver toxicity, and blindness.<ref name=liles/> In people with [[atrial fibrillation]], [[Electrical conduction system of the heart|conduction defect]]s, or [[heart block]], quinine can cause [[heart arrhythmia]]s, and should be avoided.<ref>{{Cite journal|date=2017|title=Off-label use of sildenafil in valvular heart disease should be avoided|journal=Clinical Pharmacist|doi=10.1211/cp.2017.20203778|issn=2053-6178}}</ref>{{Failed verification|date=June 2023}}

Quinine can cause [[hemolysis]] in [[G6PD deficiency]] (an inherited deficiency), but this risk is small and the physician should not hesitate to use quinine in people with G6PD deficiency when there is no alternative.<ref name=USlabel2013>{{cite web|title=US label: quinine sulfate|url=http://www.accessdata.fda.gov/drugsatfda_docs/label/2013/021799s023lbl.pdf|publisher=FDA|date=April 2013|url-status=live|archive-url=https://web.archive.org/web/20170120063419/http://www.accessdata.fda.gov/drugsatfda_docs/label/2013/021799s023lbl.pdf|archive-date=20 January 2017}}</ref>

While not necessarily an absolute contraindication, concomitant administration of quinine with drugs primarily metabolized by [[CYP2D6]] may lead to higher than expected plasma concentrations of the drug, due to quinine's strong inhibition of the enzyme.<ref name=PMID27618912/>