Hydroxychloroquine

Second-Line DMARD in Rheumatoid Arthritis
1. Especially Antinuclear Antibody positive
2. May be used in triple combination with Methotrexate and Sulfasalazine
  1. Indicated in moderate to severe disease refractory to single conventional synthetic DMARD
Systemic Lupus Erythematosus
Malaria Prophylaxis and treatment
1. Regions without Chloroquine resistance, non-severe infections
Rheumatologic off-label uses
Infectious off-label uses
1. Q Fever
NOT indicated in COVID-19 outside of Clinical Trials
1. Initial studies as of May 2020 suggest no benefit and adverse effect risk (including QTc Prolongation)

Varies significantly based on use
1. Lower doses are used in infectious disease
Dosing: Adults
1. Initial: 400 to 600 mg (may consider starting at 200 mg) orally twice daily
2. Maximum: 600 mg/day
3. Expect symptom improvement by 2 to 4 months (discontinue if no effect by 6 months)
4. Taper after 1-2 years when stable to 200 mg orally daily

Malaria Prophylaxis
1. Start 1-2 weeks before travel and continue for 4 weeks after leaving Malaria endemic region
2. Adult: 400 mg salt (310 mg base) orally once weekly
3. Child: 6.5 mg/kg salt (5 mg/kg base up to adult dose) orally once weekly
Malaria Treatment
1. Adult: 800 mg salt (620 mg base) to start, then 400 mg salt (310 mg base) at 6, 24 and 48 hours after initial dose
2. Child: 12.9 mg/kg salt (10 mg/kg base) to start, then 6.5 mg/kg salt (5 mg/kg mg base) at 6, 24 and 48 hours after initial dose

One tablet may be lethal in children (lethal dose 30 mg/kg)
Considered safe in pregnancy (all trimesters), despite initially labeled category D

Eye-related Adverse Effects
1. Epithelial Keratopathy and other Corneal disorders
2. Retinopathy
  1. Uncommon to Rare (contrast with Chloroquine)
Neurologic adverse effects
1. Early toxicity (subsides within 2 weeks)
  1. Irritability
  2. Insomnia
  3. Headache
2. Late toxicity requires medication discontinuation
  1. Tinnitus
  2. Decreased Hearing acuity
3. Very rare toxicity
  1. Myopathy or muscular weakness
4. Other adverse effects
  1. Confusion or Delirium
  2. Extrapyramidal Side Effects
  3. Hallucinations
  4. Seizures
Gastrointestinal adverse effects
1. Increased stool frequency
2. Diarrhea
3. Bloating
4. Nausea or Vomiting
Endocrine Adverse Effects
1. Hypoglycemia
Hematologic Adverse Effects
1. Neutropenia
2. Pancytopenia
Electrolyte adverse effects
1. Hypokalemia (in toxicity)
Cardiovascular adverse effects
1. Palpitations
2. Hypotension (in toxicity)
3. Premature Atrial Contractions
4. Cardiomyopathy
5. QRS Widening (in toxicity)
6. QTc Prolongation (with risk of Ventricular Tachycardia or Drug-Induced Torsades de Pointes)
  1. Increased risk when combined with other agents causing QTc Prolongation (e.g. Azithromycin)

Considered safe in Lactation
In pregnany, use if benefit outweighs risk
Monitoring
1. Routine Eye Exam every 6-12 months (including a baseline exam)
2. Complete Blood Count (CBC) periodically