Bull's-eye maculopathy associated with quinacrine therapy for malaria

Hydroxychloroquine-induced Retinal Toxicity

Long-term use of hydroxychloroquine can cause retinopathy, which may result in severe and progressive visual loss. In the past decade, hydroxychloroquine use has markedly increased and modern retinal imaging techniques have enabled the detection of early, pre-symptomatic disease. As a consequence, the prevalence of retinal toxicity in long-term hydroxychloroquine users is known to be higher than was previously estimated. The pathophysiology of the retinopathy is incompletely characterised, although significant advances have been made in understanding the disease from clinical imaging studies. Hydroxychloroquine retinopathy elicits sufficient public health concern to justify the implementation of retinopathy screening programs for patients at risk. Here, we describe the historical background of hydroxychloroquine retinopathy and summarize its current understanding. We review the utility and limitations of each of the mainstream diagnostic tests used to detect hydroxychloroquine retinopathy. The key considerations towards a consensus on the definition of hydroxychloroquine retinopathy are outlined in the context of what is known of the natural history of the disease. We compare the current screening recommendations for hydroxychloroquine retinopathy, identifying where additional evidence is required, and the management of proven cases of toxicity. Finally, we highlight the areas for further investigation, which may further reduce the risk of visual loss in hydroxychloroquine users.

An audit of the use of hydroxychloroquine in rheumatology clinics

Objective

The aim was to audit the use, indications, complications and patient information regarding HCQ treatment in rheumatology clinics in a tertiary referral centre.

Methods

During a 9-month period, we identified all patients prescribed HCQ and attending rheumatology clinics in one hospital. We established: (i) the indication for HCQ; (ii) the prevalence of HCQ overdosing based on absolute body weight (ABW); (iii) documentation of warning of risk of retinal toxicity; (iv) systemic and ocular co-morbidities; (v) ocular symptoms during treatment; and (vi) reasons for stopping HCQ.

Results

We identified 427 patients (104 male and 323 female). The cumulative dose of HCQ was lower in RA (median 365 g; range 6–1752 g) compared with SLE (450 g; 66–1788 g) (P = 0.105). The median duration of HCQ therapy was 4 years (range 0.1–13 years); 28% of patients with RA and 29% with SLE continued HCQ beyond 5 years. After adjusting for ABW and renal function, 10% (31/312) had been prescribed doses exceeding recommendations. Formal documentation of counselling on ocular complications was found in only one-third of patients. Three cases of HCQ retinopathy were identified (all of whom had RA).

Conclusion

HCQ therapy is being used for >5 years in 29% of patients with rheumatic diseases, with higher than recommended doses in ∼10% of patients. We recommend more rigorous scrutiny of the use of HCQ to reduce the risk of retinopathy.

Pharmacology of Chloroquine and Hydroxychloroquine

The 4-aminoquinolines are weak bases that are completely absorbed from the gastrointestinal tract, sequestered in peripheral tissues, metabolized in the liver to pharmacologically active by-products, and excreted via the kidneys and the feces. The parent drugs and metabolites are excreted with a half-life of elimination of approximately 40 days. However, slow release from sequestered stores of the drugs means that after discontinuation, they continue to be released into the plasma for years. Correct dosing is based on the ideal body weight of the patient, which depends on height. The 4AQs diminish autoimmunity without compromising immunity to infections.

Ophthalmic parasitosis: a review article

Ocular parasitosis in human is more prevalent in geographical areas where environmental factors and poor sanitary conditions favor the parasitism between man and animals. Lesions in the eye can be due to damage directly caused by the infectious pathogen, indirect pathology caused by toxic products, or the immune response incited by infections or ectopic parasitism. The epidemiology of parasitic ocular diseases reflects the habitat of the causative parasites as well as the habits and health status of the patient. An ocular examination may provide clues to the underlying disease/infection, and an awareness of the possibilities of travel-related pathology may shed light on an ocular presentation. This paper is a comprehensive review of the parasitic diseases of the eye. The majority of the clinically important species of parasites involved in eye infection are reviewed in this paper. Parasites are discussed by the disease or infection they cause.

New concepts in antimalarial use and mode of action in dermatology

ABSTRACT:  Although chloroquine, hydroxychloroquine and quinacrine were originally developed for the treatment of malaria, these medications have been used to treat skin disease for over 50 years. Recent clinical data have confirmed the usefulness of these medications for the treatment of lupus erythematosus. Current research has further enhanced our understanding of the pharmacologic mechanisms of action of these drugs involving inhibition of endosomal toll‐like receptor (TLR) signaling limiting B cell and dendritic cell activation. With this understanding, the use of these medications in dermatology is broadening. This article highlights the different antimalarials used within dermatology through their pharmacologic properties and mechanism of action, as well as indicating their clinical uses. In addition, contraindications, adverse effects, and possible drug interactions of antimalarials are reviewed.