The patient had been treated with hydroxychloroquine for two years prior to presentation. After thorough workup for secondary causes of QT interval prolongation hydroxychloroquine was discontinued and the patient’s QT interval shortened. Chloroquine most common side efffects Plaquenil 200 mg brcl Chloroquine for malaria in pregnancy Plaquenil and allergy testing Background/Purpose Hydoxychloroquine HCQ is widely used for the treatment of rheumatoid arthritis RA and systemic lupus erythematosus SLE with a side-effect profile including myopathy and cardiotoxicity. Acute HCQ poisoning has been reported to cause a prolonged QT interval, hypokalaemia and a prolonged QRS complex. RA itself is an independent risk factor for cardiovascular CV Long QT syndrome LQTS is a condition which affects repolarization of the heart after a heartbeat. It results in an increased risk of an irregular heartbeat which can result in palpitations, fainting, drowning, or sudden death. These episodes can be triggered by exercise or stress. Plaquenil® hydroxychloroquine sulfate is a white or practically white, crystalline powder, freely soluble in water; practically insoluble in alcohol, chloroform, and in ether. The chemical name for hydroxychloroquine sulfate is 2-4-7-Chloro-4-quinolylaminopentylethylamino ethanol sulfate 11. The patient was noted to have mild prolongation of the QT interval on electrocardiogram prior to initiation of hydroxychloroquine therapy which was exacerbated by its use and may have been caused due to toxicity from underlying renal failure. The patient was treated with mexiletine to prevent sudden ventricular arrhythmias, which was unique compared to other documented cases in which lidocaine was used. Hydroxychloroquine qt prolongation Hydroxychloroquine 200 mg tablet Kaiser Permanente, Long QT syndrome - Wikipedia Hydroxychloroquine formulationEffects of hydroxychloroquine on taste PLAQUENIL hydroxychloroquine sulfate tablets is indicated for the treatment of rheumatoid arthritis, and discoid and systemic lupus erythematosus, in patients who have not responded satisfactorily to drugs with less potential for serious side effects. Plaquenil Hydroxychloroquine Sulfate - Sanofi. Plaquenil - FDA prescribing information, side effects and uses. PLAQUENIL HYDROXYCHLOROQUINE SULFATE TABLETS, USP DESCRIPTION. Hydroxychloroquine is usually taken with food or milk to prevent stomach upset. The dosage and length of treatment are based on your medical condition and response to therapy. In children, dosage is also based on weight. Drugs associated with QT Prolongation, QTc prolongation. LITFL Further Reading. ECG Library Basics – Waves, Intervals, Segments and Clinical Interpretation; ECG A to Z by diagnosis – ECG interpretation in clinical context Make sure your doctor knows if you had a heart rhythm problem such as QT prolongation. This medicine may cause muscle and nerve problems. Check with your doctor right away if you have muscle weakness, pain, or tenderness while using this medicine. Hydroxychloroquine may cause some people to be agitated, irritable, or display other abnormal behaviors.