Quinidine and Quinine interaction

Known hypersensitivity to quinine, mefloquine, or quinidine ( 4 )

…Thrombocytopenia • Idiopathic thrombocytopenia purpura (ITP) and Thrombotic thrombocytopenic purpura (TTP) • Hemolytic uremic syndrome (HUS) • Blackwater fever (acute intravascular hemolysis, hemoglobinuria, and hemoglobinemia) • Known hypersensitivity to mefloquine or quinidine: cross-sensitivity to quinine has been documented [see WARNINGS AND PRECAUTIONS ( 5.6 )].

The concurrent use of quinine sulfate with astemizole and other CYP3A4 substrates with QT prolongation potential (e.g., cisapride, terfenadine, halofantrine, pimozide and quinidine ) should also be avoided [see WARNINGS AND PRECAUTIONS ( 5.3 )] .

…disease and preexisting conduction system abnormalities, elderly patients with sick sinus syndrome, patients with atrial fibrillation with slow ventricular response, patients with myocardial ischemia or patients receiving drugs known to prolong the PR interval (e.g. verapamil) or QRS interval (e.g. flecainide or quinidine) [see CLINICAL PHARMACOLOGY ( 12.2 )] .

Quinine may inhibit the metabolism of certain drugs that are CYP3A4 substrates and are known to cause QT prolongation, e.g., astemizole, cisapride, terfenadine, pimozide, halofantrine and quinidine.

CONTRAINDICATIONS Quinidine is contraindicated in patients who are known to be allergic to it, or who have a history of immune thrombocytopenia or have developed thrombocytopenic purpura during prior therapy with quinidine or quinine (see WARNINGS ).

Conversely, the pharmacokinetics of quinidine are not significantly affected by caffeine, ciprofloxacin, digoxin, felodipine, omeprazole, or quinine .

Labor and Delivery Quinine is said to be oxytocic in humans, but there are no adequate data as to quinidine's effects (if any) on human labor and delivery.

Pediatric use In antimalarial trials, quinidine was as safe and effective in pediatric patients as in adults.

Non-interactions of quinidine with other drugs: Quinidine has no clinically significant effect on the pharmacokinetics of diltiazem, flecainide, mephenytoin, metoprolol, propafenone, propranolol, quinine, timolol, or tocainide .