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| Interactions: | Antacids, sodium bicarbonate, thi-azide diuretics: Decreased quinidine elimination when urine pH increased. Monitor levels and ad-just dosage as needed.
Antiarrhythmics (such as amiodarone, lidocaine, phenytoin, procainamide, propranolol): Additive or antagonistic cardiac effects and additive tox-ic effects. Monitor child closely.
Anticholinergics: Additive anticholinergic effects. Monitor child closely.
Anticonvulsants (such as phenobarbital, pheny-toin): Increased rate of quinidine metabolism. Adjust dosage as needed.
Cholinergics: Quinidine antagonizes cholinergics vagal excitation effect on atria and AV node. Use other drugs to terminate paroxysmal supraven-tricular tachycardia.
Coumarin: Potentiated anticoagulant effect. Mon-itor PT and INR.
Digitoxin, digoxin: Increased (possibly toxic) serum digoxin levels. Monitor serum digoxin levels and reduce dosage as needed.
Hypotensive drugs: Additive hypotensive effects. Monitor blood pressure.
Neostigmine, pyridostigmine: Decreased effects of these drugs when used to treat myasthenia gravis. Monitor child.
Neuromuscular blockers (such as metocurine io-dide, pancuronium bromide, succinylcholine chlo-ride, tubocurarine chloride): Potentiated anti-cholinergic effects. Use of quinidine should be avoided immediately after use of these drugs; it quinidine must be used, respiratory support may be needed.
Nifedipine: Decreases quinidine levels. Adjust dosage as needed.
Phenothiazines, reserpine: Possible additive car-diac depressant effects. Monitor child.
Rifampin: Increased quinidine metabolism; de-creased serum quinidine levels. Adjust dosage as needed.
Verapamil: Significant hypotension in some children with hypertrophic cardiomyopathy. Monitor vital signs. |
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