As a flavouring agent in drinks, quinine is limited to less than 83 parts per million in the United States, and 100 mg⁄l in the European Union. Scientific
Quinine (and quinidine) are used as the chiral moiety for the ligands used in Sharpless asymmetric dihydroxylation as well as for numerous other chiral catalyst backbones. Because of its relatively constant and well-known fluorescence quantum yield, quinine is used in photochemistry as a common fluorescence standard. 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. Even from minor levels occurring in common beverages, quinine can have severe adverse effects involving multiple organ systems, among which are immune system effects and fever, hypotension, hemolytic anemia, acute kidney injury, liver toxicity, and blindness. In people with atrial fibrillation, conduction defects, or heart block, quinine can cause heart arrhythmias, and should be avoided.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. Adverse effects
Quinine can cause unpredictable serious and life-threatening blood and cardiovascular reactions including low platelet count and hemolytic-uremic syndrome/thrombotic thrombocytopenic purpura (HUS/TTP), long QT syndrome and other serious cardiac arrhythmias including torsades de pointes, blackwater fever, disseminated intravascular coagulation, leukopenia, and neutropenia. Some people who have developed TTP due to quinine have gone on to develop kidney failure.
Based on available reports, the fatality rate among diagnosed cases appears to have been about 1.7% (notably higher than the rate of 0.07% recorded among children with Kawasaki disease in Japan). A rapid risk assessment conducted by the European Centre for Disease Prevention and Control (ECDC) concluded that the overall risk to children in the European Union (EU), European Economic Area (EEA) and the UK "is considered low, based on a very low probability of [the disease] in children and a high impact of such disease. "Clusters of cases of the newly described condition have been recorded 3–4 weeks after peaks in SARS-CoV-2 viral transmission through various local communities. Such observations have been seen to support the concept that SARS-CoV-2 infection may be capable of triggering a severe form of a Kawasaki-like disease. Frequent presentation without prominent respiratory symptoms in children who do not appear to have ongoing SARS-CoV-2 infection but who have already developed antibodies suggests that the disease may be driven by a delayed, post-infectious mechanism.The median age of onset appears to be at least 7 years (compared with 2 years for Kawasaki disease, which primarily affects children under the age of 5). Male children seem to be more frequently affected (broadly in line with Kawasaki disease, where the male to female ratio is about 1.5 to 1). Many affected children appear not to have underlying health conditions, such as asthma or autoimmune disorders, and there have been relatively few reports of known congenital heart disease or preexisting cardiovascular disease.