Azithromycin is an antibiotic used to treat bacterial infections. While effective, it may cause side effects that range from mild to severe. In this article, we will discuss common and serious side effects of Azithromycin, what you should do if they occur, and how to manage them effectively. If you are considering this medication, you may also want to read about Azithromycin Usage and Dosages to ensure proper administration.
Common Side Effects
Azithromycin may cause some common side effects. If these symptoms bother you or persist, speak to your healthcare provider. These side effects occur in more than 1 in 100 people, and there are ways to manage them:
- nausea (feeling sick);
- vomiting (being sick);
- diarrhea;
- stomach pain;
- loss of appetite;
- headaches;
- dizziness or fatigue;
- changes in taste perception.
Serious Side Effects
Though less common, Azithromycin can cause serious side effects. Seek medical attention if you experience any of the following conditions:
Severe Allergic Reactions
Azithromycin may trigger severe allergic reactions. Stop taking the medication and seek immediate medical help if you experience:
- difficulty breathing or wheezing;
- rapid heartbeat;
- fever or general unwell feeling;
- swollen lymph nodes;
- swelling of the face, lips, mouth, tongue, or throat;
- difficulty swallowing or throat tightness;
- skin rash, itching, or hives;
- nausea or vomiting;
- dizziness, lightheadedness, or fainting;
- stomach cramps;
- joint pain.
Angioedema
Azithromycin may cause angioedema, a type of allergic reaction that causes swelling of the lips, face, tongue, or throat. Stop taking the medication and contact your doctor if swelling occurs. If breathing becomes difficult, seek emergency medical care immediately.
Liver Damage (Hepatotoxicity)
Liver damage is a potential side effect of Azithromycin. Contact your healthcare provider immediately if you experience:
- persistent nausea or vomiting;
- abdominal pain;
- fever;
- unusual weakness or fatigue;
- itching;
- loss of appetite;
- pale stools;
- dark urine;
- yellowing of the skin or eyes (jaundice).
If you belong to a higher-risk group, such as older adults or individuals with existing conditions, learn more about Contraindications for Different Age Groups before taking Azithromycin.
Heart Rhythm Changes
In rare cases, Azithromycin may cause severe heart rhythm disorders such as QT prolongation and torsade de pointes. The risk is higher for older adults, individuals with a family history of these conditions, or those with low potassium or magnesium levels. Inform your doctor if you experience:
- fainting;
- irregular or fast heartbeat.
Explore our article on Comparing Azithromycin with Other Antibiotics to better understand how it compares to other antibiotics in terms of safety and effectiveness.
Antibiotic-Associated Diarrhea
Azithromycin may lead to an overgrowth of Clostridioides difficile (C. diff), which can cause antibiotic-associated diarrhea. This condition can occur even up to two months after stopping the medication. Contact your healthcare provider if you develop:
- watery diarrhea;
- persistent diarrhea;
- blood in stool;
- severe stomach cramps;
- fever, occurring after starting or finishing the medication.
Infantile Hypertrophic Pyloric Stenosis (IHPS)
In infants under six weeks old, Azithromycin may cause infantile hypertrophic pyloric stenosis, a condition that affects food movement from the stomach to the intestines. Seek medical attention if your baby:
- vomits frequently;
- shows signs of irritability after feeding.
Risk Factors
Several conditions may elevate the risk of experiencing adverse effects from Azithromycin.
Kidney Disease
Azithromycin is primarily excreted through the kidneys, and individuals with kidney impairment may not effectively clear the drug from their system. This can lead to an increased concentration of the drug in the bloodstream, raising the risk of side effects like hearing loss or liver damage. If you have kidney problems, your doctor may adjust the dosage or monitor you more closely while you are on the medication.
Liver Disease
Azithromycin can affect liver function, and individuals with liver disease may face a higher risk of liver toxicity. Symptoms like jaundice (yellowing of the skin or eyes), dark urine, and upper abdominal pain may indicate liver problems. People with severe liver disease may be advised not to take Azithromycin, or their liver function may be closely monitored while they take it.
Heart Conditions
Azithromycin has been linked to QT interval prolongation, which can lead to abnormal heart rhythms (arrhythmias), particularly in patients with existing heart conditions like arrhythmia, heart failure, or previous heart attacks. People with a history of heart problems or those who take other medications that affect heart rhythm should be cautious when using Azithromycin.
Drug Interactions
Azithromycin may interact with certain medications, especially those used to treat heart conditions (e.g., antiarrhythmics), anticoagulants (blood thinners), and certain antifungal drugs. If you are taking other medications, discussing potential interactions with your healthcare provider is crucial to avoid complications. You should inform your doctor if you are taking:
- Antacids containing aluminum or magnesium may interfere with azithromycin absorption).
- Blood thinners (e.g., warfarin) and Azithromycin may enhance the effect, increasing bleeding risks.
- Drugs that prolong the QT interval (e.g., amiodarone, sotalol, quinidine) may increase the risk of heart rhythm problems.
- Diuretics (e.g., furosemide and hydrochlorothiazide) can lower potassium levels, increasing the risk of QT prolongation.
- Certain antifungal medications (e.g., fluconazole, ketoconazole) may amplify the risk of liver damage.
- HIV medications (e.g., ritonavir, efavirenz) may interact and affect the metabolism of Azithromycin.
For a detailed guide on drug interactions, visit our Azithromycin Interactions article.
Warnings for Specific Groups
Pregnant Women
Azithromycin is classified as a Category B drug by the FDA, meaning it has not shown any harm to the fetus in animal studies, but human studies are limited. It should only be used during pregnancy when necessary and only under the supervision of a healthcare provider. If you are pregnant, always inform your doctor before taking any medications.
Breastfeeding Women
Azithromycin passes into breast milk in small amounts. While it is generally considered safe for breastfeeding, it should be used cautiously. Your doctor will weigh the benefits against potential risks, especially if you are nursing a newborn or premature infant. Always consult your healthcare provider about the best approach if you’re breastfeeding.
Elderly Patients
Older adults are often more susceptible to side effects due to age-related metabolism and organ function changes. As Azithromycin can affect heart rhythm, elderly patients with a history of heart conditions, like arrhythmias or QT prolongation, may be more at risk for dangerous side effects. Close monitoring and adjustments to dosage may be necessary for this population.
Children
Azithromycin is commonly prescribed for children, especially for respiratory infections, but the dosage must be carefully tailored to the child’s age and weight. The drug should be prescribed only after careful evaluation of the risks, particularly for very young children and infants.
If you belong to a higher-risk group, such as older adults or individuals with existing conditions, learn more about Contraindications for Different Age Groups before taking Azithromycin.
Managing Side Effects
Azithromycin, like many antibiotics, can cause mild side effects, and understanding how to manage them can help you feel more comfortable:
- Nausea and Vomiting. To minimize nausea, try taking Azithromycin with food. Avoid heavy or greasy meals and stick to light, bland options like crackers, toast, or bananas. Sipping ginger tea or sucking on ginger candies may help reduce nausea. If vomiting persists, consult your doctor for advice.
- Diarrhea. Antibiotics can sometimes upset the balance of bacteria in the digestive system, leading to diarrhea. Make sure to stay hydrated by drinking water or an oral rehydration solution. Electrolyte-rich drinks can also help replace lost nutrients. If diarrhea becomes severe or lasts more than a couple of days, it could be a sign of a Clostridium difficile infection, and you should seek medical attention.
- Stomach Irritation. Avoid acidic foods (like citrus) or carbonated drinks to alleviate stomach discomfort, which can irritate the stomach lining. You might also find relief by eating smaller, more frequent meals rather than large meals. If stomach upset is a common side effect for you, your doctor might suggest taking the drug with food or adjusting the dosage.
- Skin Rash or Allergic Reactions. While uncommon, some people may experience allergic reactions like rashes or itching. These symptoms can often be managed by stopping the medication and discussing alternatives with your healthcare provider. In severe cases, if you experience swelling, difficulty breathing, or dizziness, seek emergency medical help.
You can continue taking the medication, but consult your doctor or pharmacist if these side effects persist or become bothersome. Reviewing the Precautions before starting treatment to understand potential risks is important.
Other side effects of Azithromycin may occur but are not listed here. If you suspect a side effect, contact your healthcare provider.
Long-Term Use & Resistance Concerns
Azithromycin is typically used for short-term treatment of bacterial infections, but its long-term use can lead to several concerns:
- Antibiotic Resistance. Prolonged or inappropriate use of Azithromycin and other antibiotics contributes to the growing problem of antibiotic resistance. Bacteria becoming resistant to antibiotics are harder to treat, leading to more severe infections. It is crucial to take the entire prescribed course, even if you feel better before finishing the medication, to eliminate all bacteria and prevent resistance. To learn more about the growing concerns of antibiotic resistance linked to Azithromycin, visit our Azithromycin and Antibiotic Resistance article.
- Overuse in Non-Bacterial Infections. Azithromycin should not be used for viral infections (such as the common cold or flu) because it is ineffective and could contribute to resistance. Overuse of antibiotics for non-bacterial infections is a significant factor in resistance development.
- Potential Side Effects with Long-Term Use. While Azithromycin is generally safe for short-term use, long-term use may increase the risk of side effects, including gastrointestinal issues and potential impact on heart rhythm. It is always important to evaluate the necessity of long-term antibiotic treatment carefully and explore alternative therapies if appropriate.
When to Stop Taking Azithromycin
There are several instances where you should stop taking Azithromycin immediately and seek medical attention.
Severe Allergic Reactions
If you experience signs of an allergic reaction, such as a rash, itching, swelling of the face or throat, dizziness, or difficulty breathing, stop taking the medication immediately and seek emergency medical help.
Heart Problems
If you experience irregular heartbeats, palpitations, or severe dizziness, these could be signs of a serious heart problem. You should stop the medication and seek medical attention without delay.
Severe Diarrhea or Blood in Stool
If you experience persistent diarrhea, especially if it is watery or bloody, this could be a sign of Clostridium difficile-associated diarrhea, a potentially serious side effect caused by an overgrowth of harmful bacteria in the intestines. This requires immediate medical evaluation.
Liver Damage
If you notice symptoms of liver damage, such as yellowing of the skin or eyes (jaundice), dark urine, or severe upper stomach pain, you should stop taking Azithromycin and contact a healthcare provider right away.
Hearing Loss or Ringing in the Ears
Although rare, Azithromycin can cause hearing loss, especially when taken in high doses or over long periods. If you experience ringing in the ears (tinnitus) or a loss of hearing, stop taking the medication and consult your healthcare provider.
Azithromycin can cause side effects, but understanding risk factors and how to manage mild symptoms is key to using it safely. People with kidney or liver issues, heart conditions, or other health concerns should exercise caution. Pregnant, breastfeeding and elderly patients may also need special consideration.
Long-term use is not recommended due to the risk of antibiotic resistance and other complications. Always complete the prescribed course, and if severe side effects occur, such as allergic reactions, heart issues, or severe diarrhea, stop taking the medication and seek medical help.
Responsible use under a healthcare provider’s guidance helps ensure safety and effectiveness.
If you still have any questions, visit our FAQ article where we have gathered all the most frequent questions about Azithromycin.