Hidroxicloroquina Rubió (Hydroxychloroquine Sulfate)

Hydroxychloroquine Rubió is indicated for several infectious and autoimmune conditions where modulation of the immune response is required.

• Treatment and prophylaxis of malaria caused by susceptible Plasmodium species.
• Management of rheumatoid arthritis as part of disease‑modifying therapy.
• Long‑term therapy for systemic lupus erythematosus to reduce disease activity.
• Adjunctive therapy in certain dermatologic disorders such as cutaneous lupus.
• Off‑label use in selected inflammatory conditions under specialist guidance.

• Hydroxychloroquine exerts its antimalarial and immunomodulatory actions by accumulating in lysosomes, raising intralysosomal pH and impairing enzymatic activity. This interferes with parasite digestion of hemoglobin and disrupts antigen processing. The drug also inhibits Toll‑like receptor signaling pathways, decreasing activation of dendritic cells and subsequent production of pro‑inflammatory cytokines, thereby reducing overall immune activation. Additionally, hydroxychloroquine interferes with autophagy, further limiting cellular processes that support inflammation.

Adverse reactions to hydroxychloroquine may vary in frequency and severity.

Common

• Nausea, vomiting, or general upset stomach
• Diarrhea, abdominal cramps, or loose stools
• Headache, sometimes accompanied by dizziness
• Skin rash, itching, or mild photosensitivity
• Transient visual changes such as blurred vision or difficulty focusing

Serious

• Retinal toxicity that may progress to irreversible vision loss
• Cardiac conduction disturbances, including QT interval prolongation and arrhythmias
• Severe hypoglycemia, particularly in patients receiving insulin or oral hypoglycemics
• Hemolytic anemia in persons with glucose‑6‑phosphate dehydrogenase (G6PD) deficiency
• Severe cutaneous adverse reactions, e.g., Stevens‑Johnson syndrome or toxic epidermal necrolysis
• Elevated liver enzymes indicating possible hepatotoxicity
• Peripheral neuropathy presenting as numbness or tingling in extremities

Before initiating hydroxychloroquine therapy, several precautionary considerations should be evaluated to ensure safe use.

• Baseline ophthalmologic examination is recommended because of potential retinal toxicity.
• Assess cardiac history and obtain ECG if risk factors for QT prolongation exist.
• Screen for glucose‑6‑phosphate dehydrogenase deficiency in populations at risk.
• Monitor blood glucose levels in diabetic patients, especially when combined with hypoglycemic agents.
• Evaluate liver and kidney function periodically during long‑term treatment.
• Use caution in pregnancy and lactation; benefits must outweigh potential risks.
• Discuss with a specialist before use in patients with pre‑existing autoimmune disorders.

Hydroxychloroquine may interact with other medicines, altering its efficacy or safety profile.

Avoid

• Concomitant use with other QT‑prolonging agents (e.g., certain antiarrhythmics, macrolide antibiotics).
• Co‑administration with strong CYP2D6 inhibitors that could increase plasma concentrations.
• Concurrent use with high-dose corticosteroids may increase risk of retinal toxicity.

Use with caution

• Antidiabetic drugs, as hydroxychloroquine can potentiate hypoglycemic effects.
• Digoxin, due to possible increased serum levels.
• Antiepileptic medications that may affect hepatic metabolism.
• Immunosuppressants, requiring dose adjustments and close monitoring.
• Rheumatologic disease‑modifying antirheumatic drugs (DMARDs) such as methotrexate, requiring monitoring for additive immunosuppression.