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 vs hydroxychloroquine difference Plaquenil and plastic surgery 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 It is recommended that hydroxychloroquine be discontinued if ocular toxicity is suspected and the patient should be closely observed given that retinal changes and visual disturbances may progress even after cessation of therapy. Cardiac Effects, including Cardiomyopathy and QT prolongation Postmarketing cases of Visitors to the CredibleMeds® website can use Quick Search to find drugs that are in the QTDrugs lists. Access to download the lists of QTdrugs requires registration so that users can be notified when the lists have been revised. 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 The cardiotoxicity of antimalarials, PLAQUENIL HYDROXYCHLOROQUINE SULFATE TABLETS, USP DESCRIPTION Chloroquine diphosphate salt msdsIs plaquenil toxic to the liverPlaquenil treatment for rheumatoid arthritis 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. Plaquenil - FDA prescribing information, side effects and uses. CredibleMeds Home. Risks of Hydroxychloroquine - Medsafe. QT Interval prolongation Hydroxychloroquine has the potential to prolong the QTc interval in patients with specific risk factors. Hydroxychloroquine should be used with caution in patients with congenital or documented acquired QT prolongation and/or known risk factors for prolongation of the QT internal such as • advanced age, 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. 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.