What is azithromycin?
Azithromycin is a broad spectrum antibiotic meaning it can kill bacteria from different classes. It belongs to a group of antibiotics known as macrolides which are commonly used to treat throat infections, pneumonia, ear infections, skin infections and sexually transmitted infections. It can be taken orally or as an intravenous infusion where it is injected directly into the veins. It was first approved for use in the United States in 1988.
Azithromycin is on WHO’s list of essential medicines meaning it is safe, effective and affordable when used as directed by a physician. The antibiotic acts by inhibiting the formation of protein in bacteria. Thus, the bacteria cannot grow and propagate. In 2010, azithromycin was found to be the most commonly prescribed antibiotic in outpatient medical facilities in the United States.
Azithromycin has various side effects. When taken orally, it can lead to nausea, vomiting, diarrhea and abdominal pain. In less than one percent of patients, it leads to a hypersensitivity reaction which manifests itself as itching and rashes. The most significant side effect is its ability to interfere with the electrical activity of the human heart. It does so by lowering potassium and magnesium levels which can increase or decrease a patient’s heart rate. Thus, patients with heart conditions should not take azithromycin. Monitoring the heart’s electrical activity using an electrocardiogram may also be required in select patients.
Azithromycin and Covid-19 (when used together with hydrochloroquine)
The use of azithromycin in conjunction with another drug, hydrochloroquine, which is commonly prescribed to patients with rheumatoid arthritis and lupus, against Covid-19 is controversial. This is because various investigators have published conflicting results leading to confusion, politicizing of the research process and retraction of papers from prolific medical journals.
A French study of 11 hospitalized patients showed a poor outcome. 80% of the patients were found to have naso-pharyngeal swabs still positive of SARS-CoV-2 after five to six days of treatment. Another French study involving 20 patients showed clearance of the virus from the nose and pharynx after 6 days of treatment. Finally, a more recent study showed that outpatient treatment in mild Covid-19 cases with this combination reduced hospitalization and death.
Azithromycin and Covid-19 (when used alone)
The use of azithromycin alone also has conflicting results. Two studies found that when azithromyicn was injected into infected cells, the infective viruses reduced in number. Another study found that azithromycin had no effect and only worked when combined with hydrochloroquine. The study found that azithromycin and hydrochloroquine had a synergistic effect against Covid-19. This means that the drugs were more powerful and overwhelmed the virus when used together but had no effect when either was used in isolation.
The use of azithromycin or doxycycline, another broad spectrum antibiotic, has been proposed as a prevention mechanism for front-line health workers in the United Kingdom. The National Health Service in conjunction with local universities are trying to ascertain whether daily intake of either can prevent doctors and nurses from getting infected with Covid-19. These drugs were selected because they are broad spectrum and have proven anti-inflammatory activity which is useful in managing the complications of Covid-19. Again, nothing has been proven yet. Studies are still underway and a formal consensus is yet to be announced.
Azithromycin and pregnancy
Azithromycin does not adversely affect pregnancy. So long as no heart condition is present, it can safely be prescribed to pregnant women. In addition, while it is excreted in human milk, breastfeeding an infant while taking the drug is safe. Occasionally, the infant may experience diarrhea, vomiting and rashes. These effects are mild and go away on their on as soon as the breastfeeding mother finishes her prescription.
Currently, there is is no consensus as to whether azithromycin, when used alone or in combination with hydrochloroquine, is useful against Covid-19 as published studies have opposing results. Even so, all clinical trials done so far were carried out on a small number of patients. Thus, it is impossible to predict which direction larger studies will veer towards.
Finally, it is important to note that superimposed bacterial infections can occur within the respiratory tract in moderate and severe Covid-19 cases. In this case, a broad spectrum antibiotic is indicated. Thus, for secondary bacterial infections, azithromyicn is useful. As a cure for Covid-19, whether alone or in combination with other drugs, more investigations need to be carried out for a consensus to be reached. In the absence of a heart condition, azithromycin is completely safe for pregnant women.