Organ Toxicities & Adverse Effects

The toxicity of hydroxychloroquine can manifest and present differently dependent upon the treatment period (short-term or long-term) and dosage (i.e. overdose). General signs of toxicity include:

• Headache^{1, 2}

• Dizziness^{1, 2}

• Drowsiness²

• Visual disturbances and retinal damage²

• Seizures¹

• Hypokalaemia²

• Irregular ECG rhythms (e.g. QT prolongation, torsade de pointes, ventricular tachycardia/fibrillation and cardiovascular collapse)²

• Blood disorders (thrombocytopenia, agranulocytosis and aplastic anaemia)³

• Emotional disturbances and psychosis¹

Following the initial presentation of these signs, there is risk of sudden respiratory distress and cardiac arrest^1-2,4.

References:

1. Ali S & Jones H. 23. An adverse neuropsychiatric reaction following treatment with Hydroxychloroquine: a case report. Rheumatology Advances in Practice. 2018, 2(1), pp i16-i17.

2. DrugBank. Hydroxychloroquine [Online]. 2021. [Date accessed: 17/11/2021]. Available from: https://go.drugbank.com/drugs/DB01611

3. Della Porta A, Bornstein K, Coye A, Montrief T, Long B, Parris MA. Acute chloroquine and hydroxychloroquine toxicity: A review for emergency clinicians. The American journal of emergency medicine. 2020; 38(10): 2209–2217.

4. Ilowite N & Laxer R. PHARMACOLOGY AND DRUG THERAPY. In: Cassidy J, Laxer R, Petty R, & Lindsley C. eds. Textbook of Pediatric Rheumatology. Philadelphia. Saunders Elvesier, 2010, pp 76-126.