Common use
Plaquenil, the brand name for hydroxychloroquine, is an antimalarial and disease-modifying antirheumatic drug (DMARD) widely used to treat autoimmune conditions. In rheumatoid arthritis (RA), it helps reduce joint pain, swelling, and morning stiffness, and may slow disease progression when used alone or with other DMARDs. In systemic lupus erythematosus (SLE) and cutaneous (discoid) lupus, Plaquenil can reduce flares, skin lesions, fatigue, and inflammation, and is often considered foundational therapy due to its long-term benefits and favorable risk profile under proper monitoring.
Hydroxychloroquine also plays a role in malaria. It can prevent and treat certain strains of malaria in regions where the parasite remains sensitive to 4‑aminoquinoline drugs. Geographic resistance patterns vary, so clinicians use local guidelines to determine when Plaquenil is appropriate for prophylaxis or treatment, and when alternative antimalarials are preferred.
Beyond its FDA-approved uses, hydroxychloroquine has been studied in other inflammatory conditions. However, not all potential uses are supported by high-quality evidence, and some prior off-label uses—such as for COVID‑19—are not recommended due to lack of benefit and potential cardiac risks. Always rely on current clinical guidance and a licensed clinician’s judgment before using Plaquenil for any off-label indication.
Dosage and direction
Dosing is individualized based on the condition treated, your weight, risk factors, and other medications. For rheumatoid arthritis and lupus, clinicians commonly prescribe 200 to 400 mg daily, taken with food or milk to reduce stomach upset. A key modern safety principle is to keep the maintenance dose at or below 5 mg/kg/day based on actual body weight to reduce the risk of retinal toxicity. Your prescriber will tailor the dose and schedule and may split dosing to improve tolerability.
In malaria prophylaxis, a typical regimen begins 1 to 2 weeks before travel, continues weekly during travel, and for 4 weeks after leaving the endemic area; doses and suitability depend on destination-specific resistance data. For malaria treatment in areas with known sensitivity, loading and follow-up doses are used per regional protocols. Because chloroquine resistance is common in many regions, hydroxychloroquine may not be appropriate, and alternatives should be selected by a knowledgeable clinician or travel medicine specialist.
Take Plaquenil at the same time each day to maintain steady levels, and avoid doubling doses unless your clinician instructs you to do so after a missed dose. Consistency is especially important for autoimmune disease control, as benefits often build gradually over weeks to months. Do not alter your dose or stop abruptly without discussing it with your healthcare provider, as flares or symptom rebound can occur.
Regular monitoring is part of safe use. Your clinician may order baseline and periodic eye exams, blood tests, and sometimes heart rhythm assessments depending on your risk profile and concurrent medications. Report any new visual or cardiac symptoms promptly.
Precautions
Eye health: Hydroxychloroquine can cause dose- and duration-dependent retinal toxicity, which is uncommon at recommended doses but can be irreversible if undetected. Before starting, arrange a baseline ophthalmologic exam within the first year of therapy, then annual screening after 5 years—or sooner and more frequently if you have higher risk factors such as higher daily dose (over 5 mg/kg), kidney impairment, preexisting retinal disease, or concurrent tamoxifen use. Notify your clinician immediately if you notice blurred vision, difficulty reading, or changes in color vision.
Cardiac precautions: Hydroxychloroquine can prolong the QT interval and, rarely, cause cardiomyopathy or conduction abnormalities. Risk increases with other QT-prolonging medications, electrolyte disturbances, underlying heart disease, or high drug levels. If you have a history of heart rhythm problems, heart failure, or are taking drugs such as certain antiarrhythmics or macrolide antibiotics, discuss ECG monitoring and alternative options with your clinician.
Metabolic and neurologic considerations: Hydroxychloroquine can cause hypoglycemia, even without diabetes medications. Watch for symptoms like sweating, shakiness, or confusion, and carry a quick source of glucose. Seizure disorders may be exacerbated in rare cases. Dizziness or visual changes can affect driving or operating machinery until you know how the medicine affects you.
Dermatologic and immune considerations: Hydroxychloroquine can exacerbate psoriasis and may provoke severe skin reactions in rare instances (e.g., Stevens–Johnson syndrome). If you have psoriasis, discuss risks versus benefits with your dermatologist or rheumatologist. Sun sensitivity is possible; use protection during prolonged exposure.
Kidney and liver health, G6PD, and hematology: Dose adjustments and closer monitoring may be needed with renal or hepatic impairment, as drug clearance can be reduced. While hydroxychloroquine is less associated with hemolysis than chloroquine, clinicians often exercise caution in patients with G6PD deficiency. Report unusual fatigue, pallor, easy bruising, or infections.
Pregnancy and lactation: For many patients with lupus or RA, hydroxychloroquine is continued during pregnancy because it may reduce disease activity and improve outcomes; the decision should be individualized with your obstetrician and rheumatologist. Hydroxychloroquine is excreted in breast milk in small amounts and is generally considered compatible with breastfeeding, but confirm with your clinician.
Contraindications
Do not take Plaquenil if you have a known hypersensitivity to hydroxychloroquine, chloroquine, or any 4‑aminoquinoline derivative. It is also contraindicated in individuals with preexisting maculopathy or documented retinal disease where risk of progression outweighs benefits.
Use is typically avoided or requires specialist oversight in patients with significant conduction disorders or cardiomyopathy, severe psoriasis, or porphyria. Children are more susceptible to toxicity from 4‑aminoquinoline compounds; pediatric dosing must be carefully weight-based and prescribed by a clinician experienced in pediatric use.
Possible side effects
Common side effects include gastrointestinal upset (nausea, vomiting, abdominal pain), decreased appetite, diarrhea, headache, dizziness, fatigue, and mild skin rashes or itching. Taking the medication with food and maintaining a consistent schedule can improve tolerability for many patients.
Visual symptoms such as blurred vision or difficulty focusing can occur transiently early in therapy but warrant evaluation, particularly if persistent. Long-term retinal toxicity is uncommon when dosing guidelines are followed and regular eye exams are performed, but it can be irreversible; early detection is key.
Less common but serious adverse effects include cardiomyopathy, heart rhythm changes (including QT prolongation and torsades de pointes), severe hypoglycemia, muscle weakness or myopathy, neuropsychiatric changes (mood changes, agitation), severe skin reactions, and blood dyscrasias (e.g., anemia, leukopenia). Seek urgent care for chest pain, fainting, palpitations, severe rash, yellowing of the skin/eyes, or signs of infection.
If side effects are troublesome or concerning, contact your clinician promptly. Adjusting the dose, switching dosing schedule, or considering alternative therapies may be appropriate depending on your condition and risk profile.
Drug interactions
Hydroxychloroquine has clinically important interactions. Combining with other QT‑prolonging drugs increases the risk of dangerous arrhythmias. Examples include certain antiarrhythmics (amiodarone, sotalol), macrolide antibiotics (azithromycin, clarithromycin), fluoroquinolones (levofloxacin), some antipsychotics (haloperidol), and methadone. Coordinate all prescriptions so your clinician can minimize overlap or arrange ECG monitoring.
Hydroxychloroquine may increase digoxin levels, raising the risk of toxicity; clinicians often monitor digoxin concentrations and adjust dosing. It can also enhance the effect of antidiabetic agents (insulin, sulfonylureas), increasing hypoglycemia risk. With antiepileptics, hydroxychloroquine may reduce seizure threshold.
Co-administration with tamoxifen increases the risk of retinal toxicity, warranting heightened ophthalmologic surveillance. Antacids can reduce hydroxychloroquine absorption; separate dosing by at least 4 hours. Cimetidine may increase hydroxychloroquine levels, while rifampin may reduce them. Provide your pharmacist with a full list of prescription and over-the-counter drugs, vitamins, and herbal supplements (e.g., St. John’s wort) to identify and manage interactions.
Missed dose
If you miss a dose, take it as soon as you remember unless it is near the time for your next scheduled dose. If it is close, skip the missed dose and resume your regular schedule. Do not double up to catch up. For weekly malaria prophylaxis, if you forget a dose, take it when remembered and consult your clinician about how to adjust the schedule safely.
Overdose
Overdose with hydroxychloroquine can be rapidly life‑threatening, especially in children. Symptoms may include severe drowsiness, seizures, dangerous heart rhythm abnormalities, low blood pressure, respiratory depression, and cardiac arrest. Even small amounts can be toxic to a child; store securely and use child-resistant containers.
If an overdose is suspected, call emergency services or poison control immediately. Do not wait for symptoms to appear. Emergency care may include cardiac monitoring, airway support, and specific treatments under clinician guidance.
Storage
Store Plaquenil tablets at room temperature, away from excessive heat, moisture, and direct light. Keep the bottle tightly closed and out of reach of children and pets. Do not store in the bathroom. Dispose of expired or unused medication through take-back programs or as instructed by your pharmacist; do not flush unless specifically directed.
U.S. Sale and Prescription Policy
In the United States, hydroxychloroquine (Plaquenil) is a prescription-only medication. That means federal and state laws require a valid prescription from a licensed clinician before dispensing. This framework is designed to ensure appropriate use, dosing, and safety monitoring, particularly for eye and heart health.
HealthSouth Hospital of Altamonte Springs offers a legal and structured solution for individuals who do not have a prior prescription. Through a compliant care pathway, we can coordinate access to a licensed clinician for evaluation, confirm that Plaquenil is appropriate for your condition, and ensure all necessary safety checks and counseling are completed. When clinically appropriate, the clinician issues a prescription that our pharmacy can dispense.
This approach preserves patient safety and regulatory compliance while streamlining access: identity and eligibility verification, medication reconciliation for interactions, dose confirmation within evidence-based limits, and counseling on side effects and monitoring (including ophthalmology referrals when indicated).
We do not sell Plaquenil without a valid prescription. Instead, we make it simpler to proceed without a prior prescription by connecting you to licensed care that can generate one when appropriate. Transparent pricing, pharmacist availability for questions, and secure, trackable delivery help you start therapy confidently and responsibly.
