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Hydroxychloroquine
Aka: Hydroxychloroquine, Plaquenil
- Indications
- Early Rheumatoid Arthritis
- Especially Antinuclear Antibody positive
- Systemic Lupus Erythematosus
- Malaria Prophylaxis and treatment
- Regions without Chloroquine resistance, non-severe infections
- Rheumatologic off-label uses
- Dermatomyositis
- Sjogren Syndrome
- Sarcoidosis
- Infectious off-label uses
- Q Fever
- NOT indicated in COVID-19 outside of clinical trials
- Initial studies as of May 2020 suggest no benefit and adverse effect risk (including QTc Prolongation)
- Mechanism
- Antimalarial agent used in rheumatic disease
- Modified Chloroquine to reduce Retinopathy risk
- Blocks Sodium and Potassium channels
- Pharmacokinetics
- Onset: 2-4 hours after oral dose
- Elimination half-life: 12 hours
- Efficacy: Rheumatoid Arthritis
- Response in 70-80% of cases
- Response occurs in 3-6 months
- Highest efficacy when used early in disease process
- Dose: Rheumatologic Disorders
- Varies significantly based on use
- Lower doses are used in infectious disease
- Initial: 200 mg orally twice daily
- Taper after 1-2 years when stable: 200 mg PO qd
- Precautions
- One tablet may be lethal in children (lethal dose 30 mg/kg)
- Adverse Effects
- Eye-related Adverse Effects
- Epithelial Keratopathy and other Corneal disorders
- Retinopathy
- Rare (contrast with Chloroquine)
- Neurologic adverse effects
- Early toxicity (subsides within 2 weeks)
- Irritability
- Insomnia
- Headache
- Late toxicity requires medication discontinuation
- Tinnitus
- Decreased Hearing acuity
- Very rare toxicity
- Myopathy or muscular weakness
- Other adverse effects
- Confusion or Delirium
- Extrapyramidal Side Effects
- Hallucinations
- Seizures
- Gastrointestinal adverse effects
- Increased stool frequency
- Diarrhea
- Bloating
- Nausea or Vomiting
- Endocrine Adverse Effects
- Hypoglycemia
- Hematologic Adverse Effects
- Neutropenia
- Pancytopenia
- Electrolyte adverse effects
- Hypokalemia (in toxicity)
- Cardiovascular adverse effects
- Palpitations
- Hypotension (in toxicity)
- Premature Atrial Contractions
- QRS Widening (in toxicity)
- QTc Prolongation (with risk of Ventricular Tachycardia or Drug-Induced Torsades de Pointes)
- Increased risk when combined with other agents causing QTc Prolongation (e.g. Azithromycin)
- Monitoring
- Routine Eye Exam every 6-12 months
- Management: Overdose or Toxicity
- See ABC Management
- Activated Charcoal if <1 hour from ingestion and patient maintaining own airway
- Ventricular Arrhythmia
- Cardioversion
- Lidocaine
- Wide QRS
- Bicarbonate (caution if Hypokalemia)
- Hypokalemia
- Potassium Replacement (caution)
- Seizures
- Benzodiazepines
- Hypotension
- Norepinephrine
- Other measures
- ECMO (refractory cardiovascular failure)
- References
- (2020) LexiComp, Hydroxychloroquine, accessed 5/6/2020
- Tomaszekski (2020) Crit Dec Emerg Med 14(4):32
- Matteson (2000) Mayo Clin Proc 75:669-74 [PubMed]
- Pincus (1999) Clin Rheumatol 17(6 Suppl 18):S2-S124 [PubMed]