Hcq

# Hcq ## Overview - **Classification**: Antimalarial, Disease-Modifying Antirheumatic Drug (DMARD) - **Mechanism**: Interferes with lysosomal activity, modulates immune response, and inhibits TLR9 signaling, affecting antigen presentation and cytokine production. ## Primary Indications 1. **Rheumatoid Arthritis (RA)** - Chronic autoimmune inflammatory disorder. 2. **Systemic Lupus Erythematosus (SLE)** - Chronic autoimmune disease affecting multiple organs. 3. **Malaria (Treatment & Prophylaxis)** - For certain sensitive strains. ## Adult Dosing ### Standard Dosing **Rheumatoid Arthritis (RA) & Systemic Lupus Erythematosus (SLE)** - **Dose**: Initial: **400 mg** daily. Maintenance: **200-400 mg** daily. - **Frequency**: Once daily or divided twice daily. - **Route**: Oral - **Duration**: Chronic treatment. Max **5 mg/kg actual body weight/day**. **Malaria Prophylaxis (for travelers to areas with sensitive strains)** - **Dose**: **400 mg** - **Frequency**: Once weekly (same day each week). - **Route**: Oral - **Duration**: Start 1-2 weeks pre-travel, continue during, and 4 weeks post-travel. **Malaria Treatment (Acute, uncomplicated, chloroquine-sensitive)** - **Dose**: Initial: **800 mg** (620 mg base). Then **400 mg** at 6 hrs, 24 hrs, and 48 hrs. - **Frequency**: As specified. Total dose: **2000 mg** (1550 mg base). - **Route**: Oral ### Dose Adjustments - **Renal Impairment**: CrCl <10 mL/min: Reduce dose by 50%. CrCl 10-50 mL/min: Consider reduction. - **Hepatic Impairment**: Use with caution. Consider dose reduction. Monitor for toxicity. - **Elderly Patients**: No specific adjustment, but monitor due to potential reduced organ function. ## Pediatric Dosing *(Dosing is based on actual body weight and should not exceed adult maximums)* ### Neonates (0-28 days) - **Not recommended**: Limited safety data; increased risk of toxicity. ### Infants (1-12 months) - **Malaria Prophylaxis (Chloroquine-sensitive)** - **Dose**: **6.5 mg/kg** (5 mg/kg base). - **Frequency**: Once weekly. - **Maximum**: **400 mg** per week. - **Special Notes**: Start 1-2 weeks prior, continue during, and 4 weeks post-exposure. ### Children (1-12 years) - **Juvenile Idiopathic Arthritis (JIA) & Systemic Lupus Erythematosus** - **Dose**: **3-6.5 mg/kg/day** (2.3-5 mg/kg base/day) based on actual body weight. - **Frequency**: Once daily or divided twice daily. - **Maximum**: **400 mg/day** or **5 mg/kg/day**, whichever is lower. - **Malaria Prophylaxis (Chloroquine-sensitive)** - **Dose**: **6.5 mg/kg** (5 mg/kg base). - **Frequency**: Once weekly. - **Maximum**: **400 mg** per week. - **Malaria Treatment (Acute, uncomplicated, chloroquine-sensitive)** - **Dose**: Initial: **13 mg/kg** (10 mg/kg base), then **6.5 mg/kg** (5 mg/kg base) at 6 hrs, 24 hrs, and 48 hrs. - **Frequency**: As specified. - **Maximum**: Total dose not to exceed **2000 mg** (1550 mg base). ### Adolescents (13-18 years) - **Dose**: Follows adult dosing guidelines based on weight. - **Maximum**: **5 mg/kg/day** (actual body weight) or **400 mg/day**, whichever is lower. ## Safety Information ### Contraindications - **Absolute**: Hypersensitivity to 4-aminoquinoline compounds. - **Absolute**: Pre-existing maculopathy or retinopathy. - **Relative**: Porphyria, psoriasis, G6PD deficiency. ### Common Adverse Effects - **Very Common (>10%)**: Nausea, vomiting, abdominal cramps, diarrhea. - **Common (1-10%)**: Headache, dizziness, blurred vision (transient), rash, pruritus. - **Serious but Rare**: Retinal toxicity (maculopathy, irreversible vision loss), cardiomyopathy, QT prolongation/arrhythmias, severe skin reactions (SJS, TEN), blood dyscrasias. ### Key Drug Interactions - **Digoxin**: Increased digoxin levels; monitor levels. - **Insulin/Hypoglycemics**: May potentiate hypoglycemic effects; monitor blood glucose. - **Amiodarone/QT-prolonging drugs**: Increased risk of QT prolongation and arrhythmias; avoid or use extreme caution. - **Cimetidine**: May increase HCQ levels; monitor for toxicity. - **Antacids/Kaolin**: May decrease HCQ absorption; separate administration by at least 4 hours. ## Monitoring & Follow-up - **Before Treatment**: - Baseline ophthalmologic exam (visual acuity, fundoscopy, OCT). - CBC, LFTs, renal function. - ECG (if cardiac risk factors or concomitant QT-prolonging drugs). - **During Treatment**: - **Ophthalmologic exam**: Annually after 5 years of treatment or sooner if risk factors (e.g., dose >5mg/kg/day, renal/hepatic dysfunction, tamoxifen use). - **Clinical Signs**: Monitor for vision changes (blurring, halos, central scotoma), muscle weakness, skin rash, GI upset, hypoglycemia. - Periodic CBC, LFTs, renal function at clinician discretion. ## Clinical Pearls - 💡 **Retinal Toxicity**: Irreversible vision loss is possible. Adhere strictly to **5 mg/kg actual body weight/day** maximum for chronic use. Annual eye exams are critical. - 💡 **Administration**: Take with **food or milk** to reduce GI upset. - 💡 **Onset of Action**: Therapeutic effects for RA/SLE can take **6-12 months** to fully manifest; counsel patients on patience. - 💡 **Sun Sensitivity**: Advise patients to use sun protection due to potential photosensitivity. > **⚠️ Important**: This information is for educational purposes only. Always consult current prescribing information, local guidelines, and clinical judgment before prescribing.