Hydroxychloroquine (Plaquenil): An Overview of Use Cases, Effective Doses, Side Effects

Plaquenil is one of the trade names used for an extremely sought-after antimalarial drug Hydroxychloroquine. Why does it enjoy such increased demand? First of all, it is an effective means against one of the most widespread and fatal infections on the globe — malaria. But, today, it is mainly associated with Covid-19. It is one of the promising candidates for overcoming the new virus.

The Scope of Application:

  • It is one of the most common choices for this infection as it successfully kills even those parasites that are resistant to Chloroquine (which is an acute problem in multiple regions, where this drug was broadly applied in the past). Besides, it is even safer and less toxic than Chloroquine, which is usually well-tolerated when used as prescribed. Furthermore, it can be utilized for malaria prevention — reducing the risk of catching this infection when one plans to visit a region, where it is common. By the way, do you know what malaria is and how to suspect it? It is a disease, which starts like influenza — one may notice fever, weakness, sleepiness, excessive sweating, pains all over one’s body, or other typical symptoms. But, over time, it may interfere with your liver and kidney functioning and cause drops in your blood sugar levels, seizures, and other life-endangering conditions. Thus, if you notice any symptoms resembling a cold or flu after returning from a pandemic region, do not wait for possible complications — go through a medical investigation without a delay.
  • Autoimmune problems. When using this drug for malaria therapy, doctors found out that it reduced the risk of arthritis and skin rashes, which are autoimmune reactions. As a result, it was discovered that this formulation can prevent excessive and unwanted immune reactions without suppressing the activeness of the immune system itself. Hence, now, it is authorized for rheumatoid arthritis, lupus, porphyria cutanea tarda. Namely, it relieves these conditions by reducing (or removing) inflammation, swelling, pain, skin reactions.
  • Covid-19. Based on its antiviral and immune-modulatory properties, doctors proposed a theory that it may be repurposed for treating patients infected with the new coronavirus. Yet, despite multiple clinical trials, researchers haven’t found sufficient evidence that it may relieve the symptoms of this disease, or improve patients’ chances to recover and survive. More to the point, in the course of studies, a significant number of participants faced severe side effects, including kidney/liver failures, blood diseases, heart disorders, and other life-threatening problems. Thus, it was impossible to complete most trials. Hence, as of now, this medicine must be recommended to Covid-patients within clinical studies exclusively although there are chances that it will be included in protocols in the future. Do not experiment with it without your doctor’s supervision.

Recommended Regimen of Plaquenil

Malaria Arthritis Lupus
Prevention Treatment
Dosage Adults:

400 mg



1st dose — 800 mg

further doses — 400 mg

(in 6, 24,48 hours)


1st dose — 400–600 mg per day

further doses — 200–400 mg per day


200–400 mg per day


6.5 mg per kg of body weight


1st dose — 13 mg per kg

further doses —

6.5 mg per kg






Regimen once a week repeated doses in 6, 24, 48 hours after the first one once or twice a day once or twice a day
Course duration starts 2 weeks before entering a pandemic area and finishes 4 weeks after exiting it 4 days As recommended As recommended

The Most Common Side Effects of Hydroxychloroquine

  • allergic skin reactions (like rash);
  • headaches;
  • anxiety;
  • changes in the mood;
  • digestive problems;

If you notice any of these or other side effects, ask your doctor for advice. Read on to learn other tips on safe use.

How to Administer Hydroxychloroquine: Safety and Effectiveness Aspects

  1. Take it strictly following the regimen and dosage prescribed. If needed, set alarms.
  2. Buy a suitable dose. Do not try to divide tablets into parts.
  3. It is advisable to administer it together with milk or some food. That will reduce the risk of digestive disorders.
  4. Regardless of the progress, do not change the dosage and the length of the course unless that is allowed by your doctor. Treating autoimmune conditions and removing their symptoms usually takes months, thus, be patient. Remember that exceeding the dose will increase the possibility and intensity of side effects. On the other hand, if you abandon the treatment prior to full recovery, the symptoms will come back.
  5. Warn your doctor if you suffer from allergies to drugs or foods, eye diseases, hearing disorders, kidney/liver diseases, seizures, diabetes, blood diseases, or other health problems.
  6. It may be unsafe for pregnant and breastfeeding women, so, warn your doctor about such conditions. Use contraception during the treatment course.
  7. It is not usually prescribed to children with a body weight under 31 kg.
  8. If you use any other medicines or dietary supplements (including herbals), ask your doctor whether there is a risk of interaction. For example, if you are prescribed antacids, you must make a 4-hour pause between them and Hydroxychloroquine.
  9. Keep in mind that this product may make you dizzy, thus, you must not drive or use any machinery.
  10. Alcohol and cannabis are prohibited as well — the argument is identical. If you use medical cannabis products, consult your doctor about how to minimize risks.


  1. Is Plaquenil and Hydroxychloroquine the same?

Yes. Plaquenil is one of the trade names, under which this medicine is sold.

  1. Is it sold on prescription only?

Yes. You must not apply it for self-treatment.

  1. Is it used for malaria only?

No. Due to its anti-inflammatory action, it is also prescribed to patients suffering from arthritis and other autoimmune conditions.

  1. Is it effective against SARS-CoV-2?

As of now, it is not prescribed for this purpose outside of clinical trials. This issue requires further investigation.

  1. Is it safe for children?

Yes, if their body weight is no less than 31 kg.

  1. Can it be used during pregnancy?

You must obligatorily discuss all the potential risks with your doctor since, as of now, there is no convincing research proving that it is absolutely safe for your baby.

  1. When will I feel the effect?

In the case of acute malaria attacks, the course lasts for 4 days only, but, in the case of autoimmune conditions, you must be ready for lengthy (or even life-long) therapy — you will notice the improvements in a few weeks or months only.

  1. Should I take it before or after a meal?

It is better to administer it during or after a meal as that reduces the risk of side effects on the part of the digestive system.

  1. Can I drink alcohol?

There is no data on interaction. Still, it is safer to avoid alcohol as it may make the side effects of the medicine worse.

  1. Can I drive when taking Hydroxychloroquine?

No, it is not allowed due to the risk of dizziness.