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ADVERSE EFFECTS OF HYDROXYCHLOROQUINE (PLAQUENIL) IN
THE TREATMENT OF RHEUMATOID ARTHRITIS
Khamrayev Khamza Khamidullayevich
Normurodov Jahongir
Samarkand State Medical University Department of Internal Medicine
Abstract: Hydroxychloroquine (Plaquenil) is an antimalarial drug commonly
used in the management of autoimmune diseases such as rheumatoid arthritis (RA).
While generally considered safe and well-tolerated, hydroxychloroquine is
associated with a range of adverse effects, some of which can be serious. This
article reviews the common and rare side effects of hydroxychloroquine when used
in the treatment of RA, along with mechanisms, risk factors, and clinical
implications.
Introduction:
Rheumatoid arthritis (RA) is a chronic, systemic autoimmune disorder
characterized by persistent synovial inflammation, progressive joint destruction,
and significant functional disability. It affects approximately 0.5–1% of the global
population and poses a major burden on patients' quality of life and healthcare
systems. The management of RA has evolved substantially over recent decades,
with the goal of achieving remission or low disease activity through early initiation
of disease-modifying antirheumatic drugs (DMARDs).
Hydroxychloroquine (HCQ)
, a derivative of chloroquine originally
developed as an antimalarial agent, has been widely used as a conventional
synthetic DMARD in the treatment of mild to moderate RA. It is particularly
favored due to its immunomodulatory properties, relatively low toxicity compared
to other DMARDs, and its beneficial effects in comorbid conditions such as
systemic lupus erythematosus and Sjögren’s syndrome. HCQ functions by
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interfering with lysosomal activity and antigen presentation in immune cells,
thereby reducing the inflammatory response.
Despite its established efficacy and safety profile, hydroxychloroquine is not
devoid of adverse effects. While most side effects are mild and reversible, some
can be serious and potentially irreversible, especially with prolonged use or in
predisposed individuals. The most concerning adverse effect is
retinopathy
, which
may lead to irreversible visual impairment if not detected early. Other reported side
effects include gastrointestinal disturbances, cutaneous reactions, neuromuscular
complications, and cardiotoxicity.
Given the widespread and long-term use of hydroxychloroquine in RA
management, a clear understanding of its potential adverse effects is crucial for
clinicians to ensure optimal therapeutic outcomes while minimizing risks. This
article aims to provide a comprehensive overview of the adverse effects associated
with hydroxychloroquine therapy in RA patients, highlight risk factors, and
underscore the importance of appropriate screening and monitoring strategies.
Mechanism of Action and Pharmacokinetics
Hydroxychloroquine modulates the immune system by inhibiting lysosomal
activity and antigen presentation, reducing pro-inflammatory cytokines such as
TNF-alpha and IL-1. It also interferes with toll-like receptor signaling. Its long half-
life (40-50 days) and tissue accumulation contribute to both its efficacy and
potential toxicity.
Common Adverse Effects
Common side effects include gastrointestinal disturbances (nausea, diarrhea,
abdominal pain), skin reactions (rashes, pigmentation changes), and central
nervous system symptoms (headache, dizziness). These effects are typically mild
and reversible upon drug discontinuation.
Serious and Rare Adverse Effects
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Serious adverse effects include retinal toxicity, cardiomyopathy, and
myopathy. Retinopathy is the most notable complication and can lead to
irreversible vision loss. Risk factors include long duration of therapy, high
cumulative dose, renal impairment, and pre-existing retinal disease. Cardiotoxicity,
although rare, can manifest as conduction disorders and heart failure.
Monitoring and Risk Mitigation
Regular ophthalmologic screening is recommended to detect early signs of
retinal damage. Baseline and periodic ECG monitoring may be advised for patients
with cardiovascular risk factors. Dose adjustment in renal or hepatic impairment is
crucial to minimize toxicity.
Conclusion
Hydroxychloroquine remains a cornerstone in the treatment of RA due to its
efficacy and relatively safe profile. However, clinicians must be vigilant in
monitoring for adverse effects, particularly those affecting the eyes and heart.
Patient education and individualized risk assessment play a key role in optimizing
treatment outcomes.
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