Heart Health Heart Disease Causes & Risk Factors What to Know About Azithromycin A Common Antibiotic for Treating Bacterial Infections By Richard N. Fogoros, MD Richard N. Fogoros, MD Facebook LinkedIn Richard N. Fogoros, MD, is a retired professor of medicine and board-certified internal medicine physician and cardiologist. Learn about our editorial process Updated on November 10, 2022 Medically reviewed by Anju Goel, MD, MPH Medically reviewed by Anju Goel, MD, MPH LinkedIn Anju Goel, MD, MPH, is a board-certified physician who specializes in public health, communicable disease, diabetes, and health policy. Learn about our Medical Expert Board Print Table of Contents View All Table of Contents Uses Before Taking Dosage Side Effects Warnings and Interactions Frequently Asked Questions Azithromycin is a versatile antibiotic used to treat a wide variety of bacterial infections, including those affecting the lungs, skin, and gastrointestinal system, as well as a number of sexually transmitted infections (STIs). It belongs to a class of medications called macrolide antibiotics and is derived from a similarly named antibiotic, erythromycin. It works by interfering with a bacterium's ability to produce proteins, thus inhibiting growth. Azithromycin is available as a tablet or liquid to be taken orally, an injectable solution, and eye drops. GIPhotoStock / Getty Images Brand Names of Azithromycin Zithromax Zithromax Single Dose Packets Zithromax Tri-Paks Zithromax Z-Paks Zmax (an extended-release formulation) Uses Azithromycin is used to treat and prevent many different types of infections. They include: Respiratory tract infections such as pneumonia, whooping cough, Legionnaire's Disease, and bronchitis, as well as mycobacterium avium complex (MAC), an opportunistic infection common in HIV Acute bacterial exacerbations of chronic obstructive pulmonary disease (COPD) Pharyngitis (inflammation of the pharynx) and tonsillitis Infections of the skin and other soft tissue Ear infections Bacterial conjunctivitis (pink eye) Sexually transmitted infections including chlamydia, which affects the cervix or urethra, and chancroid, which causes genital ulcers (rare in the United States) Tick-transmitted infections including babesiosis and Lyme disease Azithromycin also is used prophylactically to prevent heart infection in people having dental or other procedures and to prevent STIs in victims of sexual assault. Azithromycin is often prescribed as an alternative to penicillin for people who are allergic to it. Off-Label Uses Azithromycin sometimes is prescribed to treat moderate to severe acne. It also may be administered to children in intensive care. Azithromycin also has been investigated in combination with hydroxychloroquine to treat COVID-19, however it has not been shown to be effective. Before Taking A healthcare provider may prescribe azithromycin if you're showing signs of an infection such as fever, chills, and fatigue or pain at the infection site. They also may wait until after you've been tested for and diagnosed with a specific infection. In many cases, azithromycin will be the first antibiotic prescribed for an infection. Be aware before you take azithromycin that it is the generic name of the drug and so you may be prescribed a brand-name version of this drug, depending on your doctor's preference and your specific infection. It's also important for your practitioner to know certain details about your medical history that may affect whether azithromycin is the best antibiotic for you. Tell them if you have ever had an allergic reaction to azithromycin. Also share the names of all medications, vitamins, and supplements you currently take, if any. While some drugs pose minor interaction risks, others may contraindicate use. Precautions and Contraindications Precautions should be taken for people who have: Hepatic impairmentArrythmiaBradycardia (low heart rate)Recent heart attackOlder age Azithromycin is strongly contraindicated in certain circumstances. If any apply to you and a healthcare provider who isn't familiar with your medical history wants to prescribe azithromycin for you, tell them so they can give you a safer alternative. The contraindications for azithromycin include: A history of liver problems after taking azithromycin Long QT Interval Syndrome, a genetic condition affecting heart rhythm. In people with this condition, taking azithromycin has been associated with cardiac arrhythmias and a dangerous arrhythmia called ventricular tachycardia resulting in sudden death. Heart failure, myasthenia gravis (a condition of muscles and the nerves that control them), or kidney disease Azithromycin is commonly used during pregnancy, however it is always a idea to inform your doctor if you are pregnancy. Because azithromycin is so widely used, it is one of many antibiotics for which antibiotic resistance may be an issue, meaning it may not be fully effective against certain infections, including community-acquired pneumonia, ear infections, acute sinusitis, and methicillin-resistant Staphylococcus aureus (MRSA), a superbug with broad antibacterial resistance. Dosage A typical course of azithromycin runs for three to 10 days, depending on the type of infection being treated. The most common dosage on day one is 500 milligrams (mg) in a single dose, which might come as a pill, a liquid, or a dry powder to which water must be added, followed by 250 mg orally once a day on days 2 to 5. Zmax, an extended release suspension, is taken one time, within 12 hours of the prescription being filled. All listed dosages are according to the drug manufacturer. Check your prescription and talk to your healthcare provider to make sure you are taking the right dose for you. How to Take and Store With the exception of Zmax, which is best taken on an empty stomach (at least one hour before or two hours after a meal), azithromycin can be taken with or without food. Follow your doctor's instructions as well as those on the label. Do not take more or less than what has been prescribed. Take azithromycin until you finish the prescription, even if you feel better. If you stop taking azithromycin too soon or skip doses, your infection may return, allowing the bacteria to become resistant to antibiotics. As with all medications, store in a cool, dry place, out of sight and out of reach of children. Side Effects As with any medication, azithromycin can cause side effects. Common Many common side effects are related to the digestive system, but most are mild and should pass after your course of treatment is finished. NauseaDiarrheaVomitingStomach painHeadache Severe Immediately stop taking azithromycin and seek medical attention if you experience the following: Fast, pounding, or irregular heartbeatFaintness or dizzinessItching, hives, rash, or peelingPus-filled soresYellow eyes or pink and swollen eyesWheezing or difficulty breathing or swallowingSwelling of the face, throat, tongue, lips, eyes, hands, feet, ankles, lower legs, or skinSevere diarrhea (watery or bloody stools) and stomach cramps occurring up to two months or more after treatmentExtreme fatigue or lack of energyUnusual bleeding or bruisingLoss of appetitePain in the upper right part of the abdomenFlu-like symptomsDark urineUnusual muscle weakness or difficulty with muscle control Common and Serious Antibiotic Side Effects in Children Warnings and Interactions Azithromycin is widely used and is a common substitute for people who are allergic to other antibiotics. It's largely regarded as safe but there are some can interact with certain medications and other substances. Antacids: Do not take azithromycin simultaneously with those containing aluminum hydroxide or magnesium hydroxide such as Maalox, Mylanta, or Tums. Ask your healthcare provide or pharmacist how many hours before or after you take azithromycin you may take these medications. The extended-release suspension may be taken at any time with antacids.Certain blood thinners and drugs taken for irregular heartbeat: Your practitioner may need to change the doses of your medications or monitor you carefully for side effects if you take: Coumadin, Jantoven (warfarin); Colcrys, Gloperba (colchicine); Neoral, Sandimmune (cyclosporine); Lanoxin (digoxin); D.H.E. 45, Migranal (dihydroergotamine); Ergomar (ergotamine); Cordarone, Pacerone (amiodarone); Tikosyn (dofetilide): Procanbid (procainamide); Betapace, Sorine, (quinidine, and sotalol); Viracept (nelfinavir); Dilantin (phenytoin); or terfenadine (not available in the U.S.).Alcohol: Drinking while on azithromycin may increase side effects. Frequently Asked Questions What is a Z-Pak? A Z-Pak is a five-day course of the antibiotic Zithromax (azithromycin) distributed in a blister pack. A Z-Pak contains six 250 mg tablets. Take two tablets the first day and one tablet a day for the next four days. What does azithromycin treat? Azithromycin is an antibiotic used to treat bacterial infections such as respiratory tract infections, Lyme disease, ear infections, conjunctivitis, and skin infections. It is also sometimes prescribed as a preventive measure prior to dental procedures. Can you take azithromycin if you are allergic to penicillin? Yes. Azithromycin is a macrolide antibiotic that treats a wide spectrum of bacteria. It is commonly prescribed in place of penicillin for people with a penicillin allergy. 4 Sources Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy. MedlinePlus. Azithromycin. Apr 15, 2020. Oshikoya KA, Wharton GT, Avant D, et al. Serious adverse events associated with off-label use of azithromycin or fentanyl in children in intensive care units: A retrospective chart review. Paediatr Drugs. 2019;21(1):47-58. doi:10.1007/s40272-018-0318-9 Gbinigie K, Frie K. Should azithromycin be used to treat COVID-19? A rapid review. BJGP Open. 2020;4(2). doi:10.3399/bjgpopen20X101094 Rao GA, Mann JR, Shoaibi A, et al. Azithromycin and levofloxacin use and increased risk of cardiac arrhythmia and death. Ann Family Med. 2014;12(2):121-127. doi:10.1370/afm.1601 Additional Reading Food and Drug Administration. FDA drug safety communication: Azithromycin (Zithromax or Zmax) and the risk of potentially fatal heart rhythms. Mar 12, 2013. Ray WA, Murray KT, Hall K, et al. Azithromycin and the risk of cardiovascular death. N Engl J Med. 2012; 366:1881. doi:10.1056/NEJMoa1003833 Schwartz PJ, Woosley RL. Predicting the unpredictable: Drug-induced QT prolongation and torsades de pointes. J Am Coll Cardiol. 2016 Apr 5;67(13):1639-1650. doi:10.1016/j.jacc.2015.12.063 Voelker R. Another caution for clarithromycin. JAMA. 2018;319(13):1314. doi:10.1001/jama.2018.2945 By Richard N. Fogoros, MD Richard N. Fogoros, MD, is a retired professor of medicine and board-certified in internal medicine, clinical cardiology, and clinical electrophysiology. See Our Editorial Process Meet Our Medical Expert Board Share Feedback Was this page helpful? Thanks for your feedback! What is your feedback? Other Helpful Report an Error Submit