See also How to Use section.

Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.

Some products that may interact with this drug include: "blood thinners" (such as warfarin), penicillamine.

Other medications can affect the removal of quinine from your body, which may affect how quinine works. Examples include cimetidine, erythromycin, ketoconazole, phenytoin, rifampin, HIV protease inhibitors (such as lopinavir), ritonavir, urinary alkalinizers such as sodium bicarbonate, among others.

This medication can slow down the removal of other medications from your body, which may affect how they work. Examples of affected drugs include desipramine, digoxin, certain "statin" drugs (atorvastatin, lovastatin, simvastatin), phenobarbital, among others.

Many drugs besides quinine may affect the heart rhythm (QT prolongation), including amiodarone, dofetilide, mefloquine, pimozide, procainamide, quinidine, sotalol, macrolide antibiotics (such as erythromycin), among others. Before using quinine, report all medications you are currently using to your doctor or pharmacist.

Quinine is very similar to quinidine. Do not use medications containing quinidine while using quinine.

This medication may interfere with certain lab tests (such as certain urine tests for catecholamines, protein, steroids), possibly causing false test results. Make sure lab personnel and all your doctors know you use this drug.