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Doxycycline and Coronavirus

writtenByWritten by: Tessa Chatham Registered Nurse
Tessa Chatham Registered Nurse

Tessa Chatham Registered Nurse

Tessa is a MSN prepared Registered Nurse with 10 years of critical care experience in healthcare. When not practicing clinical nursing, she enjoys academic writing and is passionate about helping those affected by medical aliments live healthy lives.

Read more posts by this author.
reviewBy Reviewed by: Dr. Katalin Karolyi

Dr. Katalin Karolyi

Katalin Karolyi, M.D. earned her medical degree at the University of Debrecen. After completing her residency program in pathology at the Kenezy Hospital, she obtained a postdoctoral position at Sanford Burnham Prebys Medical Discovery Institute, Orlando, Florida.

March 2, 2021 Read Time - 6 minutes

Disclaimer: Doxycycline as a COVID-19 treatment is currently being developed and information is surfacing as more research on the subject becomes available. It is not a standard treatment for COVID-19 at this time. The purpose of this article is to explore possible new treatment options for COVID-19 that are based on science and valid data interpretation.

What is Doxycycline? 

Doxycycline is a tetracycline derivative antibiotic used to treat several illnesses and is used for other off-label uses. Recently, doxycycline is being explored as a possible treatment for COVID-19 disease. It is important to note that doxycycline, as a form of treatment for Coronavirus, is still ongoing and being researched in clinical studies. 

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What is Doxycycline Used For?

Doxycycline is currently used to treat community-acquired pneumonia as an empiric therapy.  Some illnesses and off-label uses for doxycycline include:

  • Lyme disease
  • Rocky Mountain spotted fever
  • Anthrax inhalation exposure
  • Acne
  • Bite wound (animal or human)
  • Cellulitis
  • Cholera
  • COPD exacerbation
  • Malaria
  • Ear infections
  • Mouth infections (periodontitis, chronic)
  • Pneumonia 
  • Sexually transmitted diseases

Doxycycline for Pneumonia

Doxycycline has been used to treat community-acquired pneumonia since 1967. It is an empiric antibiotic therapy, meaning it is used as general treatment of bacteria or fungus before specific bacteria is isolated as the cause. 

Empiric treatment is started first before the cause of pneumonia is verified by a lab microbial sample. Essentially, empiric treatment for pneumonia is an educated guess by the doctor to begin treatment based on experience and clinical presentation.

Why is Doxycycline Being Researched as COVID-19 Treatment?

Doxycycline is being researched as a COVID-19 treatment because it is an FDA-approved drug used to treat pneumonia and malaria. Repurposing other established medications that may have antiviral activity is a possible approach for treatment in early stages of illness and is seen as a safer approach than creating a brand-new drug. 

Many times, medications that are currently being used in practice are switched to be used for off-label uses. This is why many prescription medications initially made for one illness are used for other illnesses. Researchers, patients, or doctors discover benefits of drugs unrelated to the initial intention of the drug. Since doxycycline is used to treat malaria and pneumonia, it is currently being researched in how effective it is in treating COVID-19.

Similarly, hydroxychloroquine was initially researched for a COVID-19 treatment because it treated malaria. COVID-19 attacks hemoglobin cells similar to the way malaria parasites attack hemoglobin cells. Its mechanism to treat malaria is perhaps why researchers chose to look into doxycycline as a possible treatment for COVID-19, not to mention its long-standing treatment benefits with pneumonia.

Related: How to Get a COVID-19 Vaccine Doctor’s Note in Your State

What Do Clinical Trials and Studies Say About Doxycycline for Coronavirus?

Case studies show correlative relationships between potential reduction of severity of COVID-19 symptoms and doxycycline administration. These studies did not have a causal link between the use of doxycycline and reduction of symptoms, but it did show decreased mortality. In these studies, the standard dose of 100 mg twice daily or daily was administered.

Another peer reviewed study determined that doxycycline was a safer choice from previously tried hydroxychloroquine and azithromycin as a less toxic option. In this study, doxycycline was administered early in the course of illness. It was determined that doxycycline has antiviral, cardioprotective, immunomodulatory and anti-inflammatory properties; all things that help fight against COVID-19 illness. Of the patients given doxycycline, 85% recovered.

Doxycycline is not the sole treatment option for COVID-19, but it is being researched as a potential partner of other COVID-19 therapies. Doxycycline has anti-inflammatory effects and has been associated with reversal of cytokine storm, a dangerous immune response to COVID-19. 

A randomized, double-blind, placebo controlled clinical trial was conducted to research the effects of doxycycline on COVID-19. The clinical trial combined a tablet of Ivermectin and capsule of doxycycline measured against a placebo group. A placebo group is a group in which no medication is given. This clinical trial is ongoing and measures the following outcomes:

  • Presence of the virus after 7 days detected by a swab and PCR test
  • Remission of fever within 7 days
  • Remission of cough after 7 days
  • Patients requiring oxygen
  • Patients not maintaining oxygen levels above 88%
  • Number of days on oxygen therapy
  • Chest Xray improvement after day 7
  • Duration of hospitalization

Although the data is currently being collected, it is important to note that clinical trials are being conducted on the safety and efficacy of doxycycline related to the treatment of COVID-19.

What Are the Common Side Effects of Doxycycline?

Side effects of doxycycline differ in severity and frequency among patients. Some people may have mild side effects while others moderate. Side effects can be neutral, beneficial, or harmful. Common, non-harmful side effects of doxycycline include:

  • Weight loss
  • Nausea
  • Vomiting
  • Diarrhea
  • Skin sensitivity to light

Harmful side effects are referred to as adverse effects and should be reported to the doctor. These are dangerous and can signify life-threatening conditions. Swelling of your face or lips, or a noticed skin rash, should be reported to your doctor immediately when taking doxycycline.

Doxycycline Precautions and Interactions

Doxycycline should be used with caution among pregnant women as there is a causal link to staining of teeth in the developing fetus that may cause permanent discoloration (yellow, gray, brown). Doxycycline is considered safe when being taken for certain illnesses for a short term  while breastfeeding. 

Doxycycline interacts with food and other medications. Since concentration levels of doxycycline decrease with meals, particularly high-fat meals, it is recommended that each dose be taken 1 to 2 hours before meals. Over 180 prescription and OTC medications interact with doxycycline, so it is important to notify your doctor of medications you currently take to reduce the risk of interactions between drugs.

Doxycycline Dosage

The current dosage for doxycycline to treat pneumonia is 100 mg twice daily oral or intravenously for 5 days. The dosage to treat Malaria is 100 mg twice daily for 7 days. These dosages have also been used during COVID-19 research studies. 

The dosage for doxycycline varies depending on the illness being treated and comes in immediate release tablets, extended-release capsules, and intravenous solutions. Mostly 50 to 300 mg doses are prescribed for various ailments between 5 to 21 days.

  • Book on our free mobile app or website.

    Our doctors operate in all 50 states and same day appointments are available every 15 minutes.

  • See a doctor, get treatment and a prescription at your local pharmacy.

  • Use your health insurance just like you normally would to see your doctor.


Do Antibiotics Work Against the Coronavirus?

The effectiveness and safety of antibiotics to treat coronavirus is under review. Research studies and clinical trials are being conducted to test if doxycycline and other antibiotics are effective against COVID-19. 

After months into the global pandemic, there is much that we know about COVID-19 and conversely, much that we do not know. PlushCare stays up to date on the most recent treatment options for COVID-19; learn more by visiting our online Coronavirus Resource Center.

Read More About COVID-19


PlushCare is dedicated to providing you with accurate and trustworthy health information. Efficacy and Safety of Ivermectin and Doxycycline in Combination or IVE Alone in Patients With COVID-19 Infection. Accessed February 19, 2021. Clinical Outcomes of Early Treatment With Doxycycline for 89 High-Risk COVID-19 Patients in Long-Term Care Facilities in New York. Accessed February 19, 2021. Doxycycline as a potential partner of COVID-19 therapies. Accessed February 19, 2021. 

PubMed. Doxycycline treatment of high-risk COVID-19-positive patients with comorbid pulmonary disease. Accessed February 19, 2021.  

Most PlushCare articles are reviewed by M.D.s, Ph.Ds, N.P.s, nutritionists and other healthcare professionals. Click here to learn more and meet some of the professionals behind our blog. The PlushCare blog, or any linked materials are not intended and should not be construed as medical advice, nor is the information a substitute for professional medical expertise or treatment. For more information click here.

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