Hydroxychloroquine: Uses, Dosage & precautions!

Hydroxychloroquine (HCQ) is an anti malarial drug that has many anti-inflammatory properties.


  • Malaria
  • Systemic lupus erythematosus (SLE)
  • Rheumatoid Arthritis
  • Porphyria cutanea tarda
  • Dermatomyositis
  • Sarcoidosis
  • Q Fever
  • Sjögren syndrome
  • Post-lyme arthritis
  • Prevention & Management of COVID-19 (Novel coronavirus disease 2019).


Dosage forms available:

  • Tablet: 200 mg, 400 mg

Dosage guidelines:

  • COVID-19: 400 mg twice on day 1, subsequently, 200 mg twice daily for 5-7 days.
  • SLE: 200 mg twice daily or 400 mg once a day for 5 days.
  • Malaria:
    a) Prophylaxis: 400 mg once weekly on the same day each week; begin 1 to 2 weeks before travel to malarious area; continue therapy while in malarious area and for 4 weeks after leaving the area.
    b) Treatment:  800 mg once, followed by 400 mg at 6, 24, and 48 hours after initial dose.

Missed dose: Take the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not take extra medicine to make up the missed dose.

a) Administration of activated charcoal
b) Monitoring of heart & mechanical ventilation
c) Treatment and management of low blood pressure by administering IV fluids, hypertonic saline and medications to increase blood pressure.
d) IV potassium chloride.


  • Nausea
  • Vomiting
  • Diarrhea/Constipation
  • Abdominal pain
  • Headache
  • Mood swings
  • Low blood pressure
  • Hypersensitivity reaction
  • Rash/hives
  • Dry mouth & increased thirst
  • Loss of appetite
  • Numbness
  • Anxiety.


  • Damage to the retina of the eye
  • Blurred vision & visual changes
  • Anemia
  • Reduced WBC count
  • Paranoia, hallucination & psychosis
  • Depression
  • Low blood pressure
  • Cardiomyopathy
  • QT prolongation
  • Arrhythmia
  • Ringing in the ear
  • Muscle weakness & atrophy
  • Liver damage
  • Hair loss
  • Steven-Johnson Syndrome


Hydroxychloroquine is contraindicated & precaution is advised in patients with following conditions:

  • Contraindicated in patients with hypersensitivity to chloroquine derivatives.
  • Diabetes Mellitus
  • Arrhythmia
  • CHD
  • Other cardiovascular conditions
  • Psoriasis
  • Porphyria
  • G6PD deficiency
  • Eye diseases
  • Skeletal & muscular disorders
  • Mood disorders
  • Patients with alcohol addiction
  • Hepatic disease
  • Renal disease


  • Hydroxychloroquine when given in presence of anti-diabetic drugs can enhance the blood sugar lowering effect of the latter.
  • HCQ increases the serum levels of digoxin when given along with it.
  • Hydroxychloroquine given along with anti-arrhythmic agents increases the chances of QT prolongation & abnormal heart rhythm.
  • HCQ can diminish the therapeutic effect of anti-epileptic drugs when both are given along with each other.
  • HCQ enhances the toxic effect of Dapsone.
  • Quinolone drugs & Hydroxychloroquine together can have profound lowering effect on blood glucose.
  • Hydroxychloroquine when given along with some antibacterial drugs like macrolide antibiotics can lead to QT prolongation & arrhythmia.
  • Tamoxifen can enhance the adverse effects of hydroxychloroquine when given in combination.
  • Increased plasma concentration of cyclosporin is reported when combined with HCQ.


  • Pregnancy: Hydroxychloroquine is not recommended in pregnant women as some extent of damage can be caused to fetus.
  • Breast feeding: Small amounts of HCQ is excreted in the breast milk & is therefore not recommended in nursing mothers.
  • Children: Relationship of HCQ in children in not completely established.