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Chloroquine and Hydroxycholorquine

Apr 09, 2020

What are chloroquine and hydroxychloroquine?

Chloroquine and hydroxychloroquine are two different medications currently being studied for treatment of COVID-19.

While these drugs are not new and have been used successfully for other conditions (e.g. lupus, rheumatoid arthritis, and malaria), studies for use in treating COVID-19 are ongoing.

Patients should only take these medications:

  • under the direction of a medical provider
  • for an FDA-approved indication (e.g. lupus)
  • as part of a trial for the treatment of COVID-19 or
  • as part of an approved hospital protocol.

Other forms of chloroquine, such as those used in treating aquariums, are very potent and not designed for human consumption. At least one person has died after ingesting this form of chloroquine to prevent COVID-19.

What are the possible side effects?

Both medications have multiple side effects that can occur with regular use. These medications are also very dangerous in overdose.

  • Side effects in regular dosing
    • Low blood sugar in patients taking certain medications for diabetes
    • Low potassium
    • Nausea, vomiting, diarrhea
    • Irritability, mood changes
  • Patients should use caution with these medications if
    • used in combination with other medications (ask your doctor or pharmacist)
    • they have certain medical conditions (G6PD deficiency, prolonged QT syndrome)
  • Overdose
    • 1-2 tablets can be lethal in a child
    • 3-5 times the regular dose can be lethal in adults
    • Overdose may cause:
      • Confusion
      • Abnormal heart rhythms
      • Seizures
      • Death

What should I do if I am prescribed chloroquine or hydroxychloroquine by my doctor?

If you are prescribed chloroquine or hydroxychloroquine by your doctor for the treatment of COVID-19, follow the directions on the label very closely.

  • Taking more medicine than directed will not make you feel better faster.
  • Do not share these medicines with anyone, including family members.
  • Safe storage is extremely important with these medicines; keep them in their original, child-resistant container. Keep these medicines up, away, and out of sight from children.
  • Call the poison center if you have questions about these medications, if someone takes too much, or if someone accidentally takes these medications. Do not wait for symptoms to occur.
  • Healthcare professionals specializing in poisoning can be reached 24 hours a day, 7 days a week by calling 1-800-222-1222. Your call is free and confidential.


The UPCC is a 24-hour resource for poison information, clinical toxicology consultation, and poison prevention education. The UPCC is a program of the State of Utah and is administratively housed in the University of Utah, College of Pharmacy. The UPCC is nationally certified as a regional poison control center.