Plaquenil (hydroxychloroquine sulfate) is a disease-modifying antirheumatic drug (DMARD) widely prescribed for the management of chronic autoimmune disorders. As an immunomodulatory agent, it works by altering immune system activity to reduce inflammation and prevent disease progression. Its well-established efficacy and generally favorable safety profile make it a cornerstone therapy in rheumatology, dermatology, and other specialties. This medication is particularly valued for its dual role in controlling symptoms and helping to prevent long-term tissue damage.

Features

• Active ingredient: Hydroxychloroquine sulfate
• Available in 200 mg oral tablets
• FDA-approved for malaria prophylaxis and treatment, lupus erythematosus, and rheumatoid arthritis
• Mechanism: believed to interfere with antigen processing and Toll-like receptor signaling
• Generic versions available
• Typically prescribed as a long-term maintenance therapy

Benefits

• Reduces joint pain, swelling, and morning stiffness in rheumatoid arthritis
• Helps control skin lesions and systemic symptoms in lupus erythematosus
• May prevent disease flares and disease progression
• Can reduce corticosteroid dependence in chronic inflammatory conditions
• Offers convenient once or twice daily dosing for most indications
• Generally well-tolerated with proper monitoring compared to other DMARDs

Common use

Plaquenil is primarily indicated for the treatment of uncomplicated malaria, rheumatoid arthritis, and systemic lupus erythematosus. Off-label uses include the management of other autoimmune conditions such as Sjögren’s syndrome, dermatomyositis, and porphyria cutanea tarda. In rheumatology practice, it is often used as part of combination therapy with other DMARDs for enhanced efficacy. The medication is particularly valuable for patients who cannot tolerate more potent immunosuppressive agents or who require long-term maintenance therapy with minimal monitoring requirements.

Dosage and direction

The dosage of Plaquenil must be individualized based on the specific condition being treated, patient weight, and renal function. For rheumatoid arthritis and lupus, the typical maintenance dose is 200-400 mg daily, often starting with higher loading doses. Malaria prophylaxis typically involves 400 mg once weekly. Administration should occur with food or milk to minimize gastrointestinal discomfort. Regular ophthalmologic examinations are mandatory due to the risk of retinal toxicity, with baseline screening recommended before initiation and annual follow-up examinations thereafter.

Precautions

Patients should be counseled about the importance of regular ophthalmologic monitoring, as retinal damage can occur even after discontinuation of therapy. Those with pre-existing retinal disease, hepatic impairment, or glucose-6-phosphate dehydrogenase deficiency require careful risk-benefit assessment. Periodic complete blood counts should be performed to monitor for blood dyscrasias. Patients should be advised that therapeutic effects may not be apparent for several weeks to months after initiation of therapy. Caution is advised in patients with psoriasis, as hydroxychloroquine may exacerbate the condition.

Contraindications

Plaquenil is contraindicated in patients with known hypersensitivity to hydroxychloroquine, 4-aminoquinoline compounds, or any component of the formulation. Additional contraindications include pre-existing macular changes or visual field defects attributable to 4-aminoquinoline compounds. The medication should not be used in patients with known glucose-6-phosphate dehydrogenase deficiency for malaria treatment. Concomitant use with other drugs known to cause retinal toxicity or hepatotoxicity is generally contraindicated.

Possible side effect

Common adverse effects include gastrointestinal symptoms such as nausea, vomiting, diarrhea, and abdominal cramps. Dermatological reactions including pruritus, pigmentary changes, and hair bleaching or loss may occur. Neurological side effects can include headache, dizziness, and nervousness. Ocular toxicity represents the most serious concern, with potential for irreversible retinopathy characterized by paracentral scotomas and pigmentary changes. Rare but serious adverse effects include cardiomyopathy, skeletal muscle myopathy, and blood dyscrasias such as agranulocytosis and aplastic anemia.

Drug interaction

Plaquenil may interact with digoxin, increasing serum digoxin concentrations. Concomitant use with other QT-prolonging agents may increase the risk of serious cardiac arrhythmias. Antacids and kaolin may reduce absorption of hydroxychloroquine and should be administered at least 4 hours apart. The medication may enhance the effects of insulin and oral hypoglycemic agents, potentially necessitating dosage adjustments. Concomitant use with hepatotoxic drugs may increase the risk of liver injury. Plaquenil may decrease the efficacy of neostigmine and pyridostigmine in myasthenia gravis.

Missed dose

If a dose is missed, patients should take it as soon as remembered unless it is almost time for the next scheduled dose. In that case, the missed dose should be skipped and the regular dosing schedule resumed. Patients should never double the dose to make up for a missed administration. For weekly malaria prophylaxis, if a dose is missed, instruct the patient to take it as soon as possible and then resume the regular weekly schedule. If the missed dose is not remembered until the day of the next dose, only one dose should be taken.

Overdose

Hydroxychloroquine overdose constitutes a medical emergency requiring immediate treatment. Symptoms may include headache, drowsiness, visual disturbances, cardiovascular collapse, convulsions, and hypokalemia. Cardiac manifestations include QRS and QT prolongation, ventricular arrhythmias, and hypotension. Management involves immediate gastric lavage or activated charcoal if ingestion occurred within one hour. Cardiovascular monitoring for at least 24 hours is essential. Treatment is primarily supportive, with particular attention to maintaining adequate ventilation, managing seizures, and correcting electrolyte imbalances. Dialysis is not effective due to extensive tissue binding.

Storage

Plaquenil tablets should be stored at controlled room temperature between 20°C to 25°C (68°F to 77°F) in their original container. Protect from light and moisture, and keep the bottle tightly closed. Keep out of reach of children and pets. Do not store in bathroom cabinets where humidity levels may fluctuate. Discard any medication that has passed its expiration date or shows signs of deterioration. Proper disposal methods should follow local regulations for pharmaceutical waste, typically through medication take-back programs.

Disclaimer

This information is provided for educational purposes only and does not constitute medical advice. The content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read in this product information. Individual patient responses to medication may vary, and only a healthcare professional can determine appropriate therapy based on specific clinical circumstances.

Reviews

Clinical studies consistently demonstrate Plaquenil’s efficacy in reducing disease activity scores in rheumatoid arthritis and lupus patients. Many rheumatologists report satisfactory disease control in approximately 60-70% of patients, with particular benefit for constitutional symptoms and mucocutaneous manifestations. Patient-reported outcomes often indicate improved quality of life measures, though some note the delayed onset of therapeutic effect as a limitation. The medication receives generally positive evaluations for its tolerability profile compared to other DMARDs, though the requirement for regular eye examinations remains a concern for some patients. Long-term observational studies support its continued use as a foundational therapy in autoimmune disease management.