What you need to know about Plaquenil (hydroxychloroquine), a drug being tested to treat the novel coronavirus


The below is not a substitute for medical advice. It is a summary, and some information has been omitted. If you would like more detailed information about Plaquenil, please consult your doctor, a pharmacist, or the drug manufacturer. 

For patients with COVID-19, the disease caused by the novel coronavirus, doctors and hospitals must focus on managing the symptoms associated with the respiratory illness. There is not currently an FDA-approved treatment. 

However, some early studies have shown promising results regarding the use of Plaquenil (hydroxychloroquine sulfate), an anti-inflammatory, anti-malarial, antiparasitic, and immuno-modulatory prescription medication. 

We put together a guide to this medication to help you stay in the loop. 

What is Plaquenil normally used to treat? 

Plaquenil is used to prevent and treat malaria. It is also used to treat lupus and both acute and chronic rheumatoid arthritis. For malaria, the medication is theorized to work by preventing the malaria parasite from breaking down hemoglobin in red blood cells. For lupus and rheumatoid arthritis, which are autoimmune diseases, Plaquenil works by modulating the body’s immune system. 

How long has Plaquenil been around? 

We can trace the roots of the medication back to the invention of anti-malarials in 1820, when the chemists Pierre Joseph Pelletier and Joseph Canentou created the early version of the medication (quinine) from Cinchona bark, a natural extract that had been used since the 1630s to treat malaria in Peru. In the 1950s, hydroxychloroquine was created (derived from quinine) to treat lupus and rheumatoid arthritis as well. 

Is Plaquenil currently available? 

Generally, Plaquenil is available only to patients with a valid prescription who are using it for the FDA-approved treatments—in other words, for immune disorders like malaria, lupus, and rheumatoid arthritis. It has not yet been approved for the treatment of the novel coronavirus. That being said, there are some exceptions. It has been approved in the U.S. for compassionate use, which means severely ill patients can be given Plaquenil if there are no other treatment options. Some doctors are also choosing to prescribe Plaquenil off-label to treat COVID-19. If you want to learn more about using Plaquenil in relation to the coronavirus, especially our recommendations as pharmacists to physicians, you can read more here

Why are doctors interested in Plaquenil? 

Doctors are interested in Plaquenil because there is anecdotal evidence from South Korea, China, and other countries that this drug may decrease severity of the disease, as well as the time of hospitalization. Since there are no FDA-approved treatments for COVID-19, doctors are trying to empirically treat the disease with drugs they have available. Plaquenil is one of those drugs. In vitro (in test tube/lab) studies show that it may work by inhibiting viral replication and fusion of the virus to cell membrane at the standard used doses. For this reason, despite a lack of rigorous clinical testing to evaluate Plaquenil in the human body, some doctors are prescribing the drug to treat COVID-19.

Is Plaquenil safe? 

As with any prescription medication, it is up to you, your doctor, and your pharmacist to decide if the benefits outweigh the risks. Incorrect use of Plaquenil can have serious health consequences:  

  1. Eye/Retinal toxicity

Plaquenil can cause potentially irreversible retinopathy. This is mostly associated with high daily doses and increased duration of therapy (1-5 years). Concurrent use of other medications, lower body weight, pre-existing eye conditions, and kidney impairment all put you at higher risk of retinal toxicity. 

  1. Cardiovascular effects

Plaquenil can cause cardiomyopathy, resulting in cardiac failure that may be fatal. It can also cause different types of arrhythmias, which are irregular heartbeats and murmurs.

  1. Dermatologic disorders

Skin dermatitis and skin discoloration can occur with use of Plaquenil. If you have psoriasis, this medication has a high likelihood of exacerbating the condition. Severe rash, photosensitivity, and itching can also occur.

  1. Neuromuscular effects

Myopathy may occur in patients. Muscular weakness, atrophy, abnormal muscle reflex and control must be monitored during and after use.

  1. Diabetic complications

Diabetic patients must take extra precaution to make sure their blood sugar does not drop dramatically. Hypoglycemia in diabetic patients has been reported.

  1. Pregnancy

Plaquenil should be avoided if you are pregnant or breastfeeding.

The above health consequences are not very common, particularly with the durations and dosages of COVID-19 treatment that are recommended by the researchers from South Korea, China, Belgium, and others. These groups recommend treatment between 5-10 days with at most a dosage of 400 mg/day. Generally speaking, Plaquenil side effects tend to manifest with treatment exceeding these recommended dose and duration limits.

That being said, side effects can still occur with shorter drug therapy durations and lower doses. Additionally, underlying conditions and other health factors can affect the risk and side effects associated with the drug.

In addition to the more serious health consequences listed above, Plaquenil can also cause the following more common side effects:

  • Dizziness
  • Headache
  • Lack of appetite
  • Nausea and vomiting
  • Abdominal pain
  • Weight loss
  • Hair discoloration
  • Hair loss
  • Anxiety
  • Diarrhea

These are not all of the precautions and side effects associated with Plaquenil. Please speak to your healthcare provider to discuss specific questions about this medication and the appropriateness of utilizing this drug.

Does Plaquenil interact with any other drugs?

You should always inform your doctor of every medication you are currently taking before starting a new one. Plaquenil can cause serious side effects, including liver and heart problems, when taken concurrently with certain other drugs. Please check with a pharmacist before you begin taking Plaquenil.  

Medical disclaimer: Every effort has been made to ensure that the information provided is accurate, up-to-date and complete, but no guarantee is made to that effect. In addition, the drug information contained herein may be time sensitive and should not be utilized as a reference resource beyond the date hereof. This material does not endorse drugs, diagnose patients, or recommend therapy. This information is a reference resource designed as a supplement to, and not a substitute for, the expertise, skill , knowledge, and judgement of healthcare practitioners in patient care. The absence of a warning for a given drug or combination thereof in no way should be construed to indicate safety, effectiveness, or appropriateness for any given patient.

Honeybee Health does not assume any responsibility for any aspect of healthcare administered with the aid of materials provided. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the substances you are taking, check with your doctor, nurse, or pharmacist.

Dr. Jessica Nouhavandi

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