With the recent announcement by US President Donald Trump that Chloroquine or Hydroxychloroquine may be useful for the treatment of the new pandemic virus COVID-19, there have been questions about the safety of these medications and the difference between the two medications.

I will attempt to describe these medications as simply as possible while pointing out precautions, side effects, similarities and differences.

History

Chloroquine is a synthetic drug which was studied and researched as early as 1934 by the Germans under the name of Resochin. It has been used and is still being used around the world for the prevention and treatment of Malaria especially where the risk of chloroquine-resistant malaria is still low. It has also been widely used to treat Rheumatoid arthritis and Lupus erythematous.

Chloroquine is available as tablets, capsules, syrups and injections. It is important to note that oral formulations may be either Chloroquine Phosphate or Chloroquine Sulfate while the injection is Chloroquine hydrochloride. Therefore, it would be wise for prescribers to write the prescription clearly and state the dose as the chloroquine base or the Chloroquine salt.

****To avoid excessive dosage in obese patients, the doses of Chloroquine and Hydroxychloroquine should be calculated on the basis of ideal body-weight.****

Hydroxychloroquine on the other hand is a hydroxylated form of chloroquine with similar actions and attributes of chloroquine. It is generally less toxic than Chloroquine especially with long term use.

Toxicity, precautions and side effects

The same toxicity, precautions and side effects apply to both Chloroquine and Hydroxychloroquine. However, they are usually less with Hydroxychloroquine.

Toxicity
Taken in proper doses, Chloroquine is a very safe drug; however a single dose of 30mg/kg (13.61mg/lb.) may be fatal.

Precautions

Use with caution in patients with psoriasis, history of epilepsy, myasthenia gravis, and severe gastrointestinal disorders. Avoid using with other hepatotoxic medications and patients with G6PD deficiency should use with care. Other precautions include patients with hepatic (liver) or renal (kidney) impairment.

For pregnant and breast-feeding patients, the prescriber should weigh the benefits versus the risks. In this case, just like in malaria; the benefits of treating COVID-19 most likely outweigh the risks.

*****To avoid excessive dosage in obese patients, the doses of Chloroquine and Hydroxychloroquine should be calculated on the basis of ideal body-weight.*****

Side-effects
These include gastrointestinal disturbances, headache, hypotension, visual disturbances, depigmentation or loss of hair, rashes and pruritus to mention a few.

For COVID-19

Hydroxychloroquine is widely prescribed in the United States and a lot of US prescribers are familiar with Hydroxychloroquine so I would think that would be a wise choice for US patients. On the other hand Chloroquine is widely prescribed in Africa and some other continents; so their prescribers can start with Chloroquine and later move to the less toxic Hydroxychloroquine.

The only dosage I could find was from the WHO and is the proposed dose of hydroxychloroquine 400mg per day for 5 days and it is still undergoing Clinical trials

Conclusion

Hopefully, these two affordable and widely available medications will prove successful in the fight against the COVID-19 virus.

References

British National Formulary 66 pg 432 (bnf.org)

Goodman & Gilman, The Pharmacological Basis of Therapeutics, 11th edition 2006

https://www.who.int/blueprint/priority-diseases/key-action/Table_of_therapeutics_Appendix_17022020.pdf?ua=1

  1. As per this article***The only dosage I could find was from the WHO and is the proposed dose of hydroxychloroquine 400mg per day for 5 days and it is still undergoing Clinical trials*** It says for 5 days. It also refers to****To avoid excessive dosage in obese patients, the doses of Chloroquine and Hydroxychloroquine should be calculated on the basis of ideal body-weight.****Everything else I have read says 200 mg once a week & does not mention weight. So which is correct please. I have ordered mine and should be receiving it in 2 weeks. I am over weight, obese. I weight 230, female. I have chronic lung condition, age 72

    • Hi K,
      This article was written over a year ago and there has been a lot of ongoing research since then. You did not state whether you tested positive for COVID-19. The most important thing at this point is that you should be under the care of a physician (doctor) who would be up to date on current research. Do not self medicate on prescription medications.

      Do not take Hydroxychloroquine without the involvement of your doctor.

      If you are just thinking of preventative measures, please continue to observe the social distancing precautions, wearing of face masks and washing of hands. You can also take OTC (over the counter) supplements that contain Zinc, Vitamin D3 and Vitamin C in the active ingredients.

      • I got 200mg Hydroxychloroquine. Was to take one each day for 5 days then once a week for prevention. From Americas frontline doctors . Com.

  2. I have a severely compromised immune system. My doctor (pulmonologist) will not get me any preventative meds for covid. I do not have covid and have been tested a few times, all were negative results. I was in the hospital March 2020 with Influenza A and double pneumonia. Got out and have been on oxygen 24/7 since. I have been trying to set up a consultation with Frontline doctors but seem to have a problem getting my drivers license to transfer to their form which they require. I am pretty computer illiterate. I feel like I’m just biding time until I get covid at which time, there is no double in my mind that I will die from it .

  3. I am a firm believer in that ALL doctors and pharmacists need to take a stand in this farce going on. It is unthinkable that people who take oaths to do no harm are backing this government slaughter of innocent people world wide.

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