Hidroxicloroquina Laboratorios Gebro Pharma, S.A. (Hydroxychloroquine Sulfate)

Hydroxychloroquine is indicated for several infectious and autoimmune conditions, reflecting its dual antimalarial and immunomodulatory properties.

• Treatment and prophylaxis of malaria caused by susceptible Plasmodium species.
• Long‑term management of rheumatoid arthritis to reduce joint inflammation and damage.
• Control of disease activity in systemic lupus erythematosus, including skin and joint manifestations.
• Adjunct therapy for certain dermatologic disorders such as chronic cutaneous lupus erythematosus.
• Investigational use in other autoimmune disorders under clinical study.

• Hydroxychloroquine interferes with the parasite’s ability to detoxify heme by inhibiting heme polymerization within the digestive vacuole, leading to toxic accumulation. In immune cells, the drug raises lysosomal pH and disrupts antigen processing, which reduces presentation of autoantigens and dampens Toll‑like receptor signaling, thereby modulating the inflammatory response in autoimmune diseases. These combined actions contribute to its efficacy against malaria parasites and its therapeutic effect in rheumatic conditions.

Hydroxychloroquine may cause a range of adverse reactions, varying from mild to severe, that are reported in clinical use.

Common

• Nausea, vomiting or abdominal discomfort.
• Diarrhea or loose stools.
• Headache or dizziness.
• Skin rash or mild pruritus.
• Muscle weakness or myalgia.
• Loss of appetite.
• Changes in taste.

Serious

• Retinal toxicity leading to visual disturbances, potentially irreversible.
• Cardiac rhythm abnormalities such as QT prolongation.
• Severe hypoglycemia, especially in diabetic patients.

When prescribing hydroxychloroquine, clinicians consider several precautionary factors to minimize risk and ensure appropriate use.

• Assess baseline retinal function; periodic ophthalmologic examinations are recommended during long‑term therapy.
• Evaluate cardiac history, especially for conduction disorders or concomitant QT‑prolonging agents.
• Monitor blood glucose in patients with diabetes, as the drug may enhance hypoglycemic effects.
• Use with caution in patients with hepatic or renal impairment; dose adjustments may be required.
• Counsel women of childbearing potential about pregnancy category B and advise on contraception.
• Review complete medication list to identify potential drug interactions.

Hydroxychloroquine can affect the pharmacokinetics or pharmacodynamics of several medicines, necessitating careful management.

Avoid

• Medications that significantly prolong the QT interval (e.g., quinidine, sotalol, certain macrolide antibiotics).
• Strong CYP2D6 inhibitors that may increase hydroxychloroquine plasma levels (e.g., fluoxetine, paroxetine).

Use with caution

• Other antimalarials or immunosuppressants, which may increase risk of toxicity.
• Drugs that lower seizure threshold, such as bupropion, when combined with hydroxychloroquine.
• Antidiabetic agents, because hydroxychloroquine can potentiate hypoglycemia.
• Anticoagulants, as hydroxychloroquine may affect INR values.