Pharm
Hydroxychloroquine
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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 Disorder
s
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
Dose
Malaria
Malaria Prophylaxis
Start 1-2 weeks before travel and continue for 4 weeks after leaving
Malaria
endemic region
Adult: 400 mg salt (310 mg base) orally once weekly
Child: 6.5 mg/kg salt (5 mg/kg base up to adult dose) orally once weekly
Malaria
Treatment
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
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
Precautions
One tablet may be lethal in children (lethal dose 30 mg/kg)
Considered safe in pregnancy (all trimesters), despite initially labeled category D
Adverse Effects
Eye-related Adverse Effects
Epithelial Keratopathy and other
Cornea
l 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 Effect
s
Hallucination
s
Seizure
s
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
Palpitation
s
Hypotension
(in toxicity)
Premature Atrial Contraction
s
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)
Seizure
s
Benzodiazepine
s
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]
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