Hydroxychloroquine 200 mg

What is Hydroxychloroquine

• Hydroxychloroquine (HCQ) is a derivative of chloroquine; it belongs to the 4-aminoquinoline class.

• It has antimalarial activity and immunomodulatory / anti-inflammatory properties, which is why it is used in autoimmune diseases like rheumatoid arthritis and lupus.

Drug Form & Strength

• The 200 mg tablet is a common oral form. Each 200 mg hydroxychloroquine sulfate tablet corresponds to about 155 mg of the base.

• Tablets are film-coated for oral use. They should be taken with a meal or milk to reduce gastrointestinal irritation.

How It Works (Mechanism)

• For malaria: it interferes with parasite communication, growth, and replication within red blood cells.

• In autoimmune disease: the exact mechanisms are not completely understood. It is believed to modify the immune response, reduce inflammation, reduce antigen presentation, inhibit toll-like receptor activity, and interfere with some intracellular processes.

Indications (What It’s Used For)

Hydroxychloroquine is used for:

1. Malaria

   • Treatment of certain types of malaria.

   • Often used for prophylaxis in endemic areas.

2. Autoimmune / Rheumatic Diseases

   • Systemic lupus erythematosus (SLE)

   • Discoid lupus & other cutaneous lupus forms

   • Rheumatoid arthritis

   • Some dermatological conditions worsened by sunlight (photosensitive dermatoses)

Dosage

Because hydroxychloroquine has risks that increase with dose & duration, doses are carefully set, often based on weight.

• Typical maintenance dose in many autoimmune conditions: 200-400 mg daily after response is achieved.

• Some start with higher initial doses for certain conditions, then taper.

• Maximum safe dose is often limited by risk of toxicity, especially ocular toxicity (retinopathy). For many guidelines, that means not exceeding about 5 mg/kg/day (actual body weight). Earlier guidelines used 6.5 mg/kg ideal weight, but newer recommendations tend toward 5 mg/kg.

• In malaria, dosing is different (loading doses, multi-day regimens).

Pharmacokinetics

• Absorption: Hydroxychloroquine is well absorbed orally; taking with food can improve tolerability.

• Distribution: Widely distributed throughout body, including to skin, eyes, etc. It accumulates over time, which is part of both its therapeutic effect (for autoimmune conditions) and risk (especially for retina).

• Elimination: Mainly via kidneys; also some hepatic metabolism. Plasma half-life is long.

Side Effects & Risks

Hydroxychloroquine is generally considered safe when used correctly, but there are risks — some mild, some serious, especially with higher doses, long duration, or in certain risk-groups.

Common / Mild Side Effects

• Gastrointestinal upset: nausea, vomiting, diarrhea, abdominal cramps. WebMD+2FDA Database+2

• Headache, dizziness. Medicines.org.uk+1

• Skin reactions: mild rash, photosensitivity. Medicines.org.uk+2Medex+2

Serious / Less Common Risks

• Retinopathy / Eye damage: Risk increases with cumulative dose, duration of use, high daily dose, older age, kidney disease, pre-existing eye problems. Regular eye exams are recommended (baseline and annually).

• Cardiac issues: Including QT interval prolongation, arrhythmias, rarely cardiomyopathy. Use caution if patient has cardiac disease or using other drugs that affect QT interval.

• Hypoglycemia: Can lower blood sugar; can be serious.

• Hepatotoxicity: Abnormal liver tests; rare but serious liver injury.

• Blood disorders: Very rarely, bone marrow suppression (anemia, leukopenia, thrombocytopenia) especially in certain risk groups.

• Skin reactions: Severe ones like Stevens-Johnson syndrome or toxic epidermal necrolysis are rare but possible.

• Neuromuscular effects: Muscle weakness, sometimes neuropathy.

Monitoring, Contraindications & Precautions

• Before starting therapy: eye exam (baseline).

• Periodic monitoring: visual acuity, color vision, retinal exam; liver function tests; if relevant, ECG for cardiac risk; renal function in those with impaired kidneys.

• Dose adjustment in renal impairment.

• Contraindications: known hypersensitivity to hydroxychloroquine or related compounds; pre-existing retinopathy; caution/avoid in certain heart conditions; some skin conditions (e.g. psoriasis) may worsen.

What the 200 mg Dose Means

• 200 mg is often the maintenance dose, especially in autoimmune diseases, once the condition is under control.

• It is equivalent to 155 mg base (important when comparing amounts in studies or when base/dose is given in base form versus salt).

• It may be adjusted up or down depending on weight, kidney/liver function, duration of treatment, and risk of side effects.

Special Considerations

• Long duration of use increases risk of cumulative side effects (especially retinopathy). Therefore, the lowest effective dose for the shortest period necessary is preferred.

• In pregnancy: HCQ is often continued in lupus pregnancies because it helps reduce flares and risk in both mother and fetus; but still medical supervision is essential.

• Drug interactions: caution with other medicines that prolong QT interval; also interactions with drugs affecting liver metabolism; also risks of hypoglycemia if combined with antidiabetic drugs.