Medical Editor: John P. Cunha, DO, FACOEP
Zithromax (azithromycin) is a semi-synthetic macrolide antibiotic used for treating otitis media (middle ear infection), tonsillitis, laryngitis, bronchitis, pneumonia, and sinusitis caused by susceptible bacteria. Zithromax is also is effective against several sexually transmitted infectious diseases (STDs) such as nongonococcal urethritis and cervicitis. A generic formulation of Zithromax is available. Common side effects of Zithromax include:
- diarrhea or loose stools,
- abdominal or stomach pain,
- vomiting, and
- pain or redness at the injection site.
Tell your doctor if you have unlikely but serious side effects of Zithromax including:
- hearing changes (e.g., ringing in the ears, hearing loss),
- swelling legs or feet,
- eye problems (e.g., drooping eyelids, blurred vision),
- slurred speech,
- muscle weakness,
- persistent nausea or vomiting,
- severe abdominal or stomach pain,
- unusual weakness or tiredness,
- change in the amount of urine,
- dark urine, or
- yellowing skin or eyes.
A typical oral dose of Zithromax consists of 500 mg for 1 day then 250 mg for 4 days. A typical intravenous dose consists of 500 mg for 2 days followed by 500 mg orally daily for an additional 5-8 days. Zithromax may interact with digoxin, live bacterial vaccines, lovastatin, nelfinavir, warfarin, hormonal birth control (such as pills, patch, or ring), amiodarone, disopyramide, dofetilide, dronedarone, ibutilide, pimozide, procainamide, quinidine, and sotalol. Tell your doctor all medications and supplements you use. Tell your doctor if you are pregnant or plan to become pregnant before using Zithromax; it is unknown if it will affect a fetus. Zithromax passes into breast milk. Consult your doctor before breastfeeding.
Our Zithromax Side Effects Drug Center provides a comprehensive view of available drug information on the potential side effects when taking this medication.
This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.
Tell your doctor immediately if any of these unlikely but serious side effects occur: hearing changes (e.g., ringing in the ears, hearing loss), swelling legs/feet, eye problems (e.g., drooping eyelids, blurred vision), slurred speech, muscle weakness, persistent nausea/vomiting, severe abdominal/stomach pain, unusual weakness/tiredness, change in the amount of urine, dark urine, yellowing skin/eyes.
Use of this medication for prolonged or repeated periods may result in oral thrush or a new vaginal yeast infection. Contact your doctor if you notice white patches/sores in your mouth, a change in vaginal discharge, or other new symptoms.
Get medical help right away if any of these rare but serious side effects occur: severe dizziness, fainting, fast/irregular heartbeat.
This medication may rarely cause a severe intestinal condition (Clostridium difficile-associated diarrhea) due to a type of resistant bacteria. This condition may occur during treatment or weeks to months after treatment has stopped. Do not use anti-diarrhea products or narcotic pain medications if you have any of the following symptoms because these products may make them worse. Tell your doctor immediately if you develop: persistent diarrhea, abdominal or stomach pain/cramping, blood/mucus in your stool.
A very serious allergic reaction to this drug is rare. However, seek immediate medical attention if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.
An allergic reaction to this medication may return even if you stop the drug. If you have an allergic reaction, continue to watch for any of the above symptoms for several days after your last dose.
This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.
In the US -
Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.
Read the entire patient information overview for Zithromax Injection (Azithromycin)
Clinical Trials Experience
Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice.
In clinical trials of intravenous azithromycin for community-acquired pneumonia, in which 2 to 5 IV doses were given, the reported adverse reactions were mild to moderate in severity and were reversible upon discontinuation of the drug. The majority of patients in these trials had one or more comorbid diseases and were receiving concomitant medications. Approximately 1.2% of the patients discontinued intravenous ZITHROMAX therapy, and a total of 2.4% discontinued azithromycin therapy by either the intravenous or oral route because of clinical or laboratory side effects.
In clinical trials conducted in patients with pelvic inflammatory disease, in which 1 to 2 IV doses were given, 2% of women who received monotherapy with azithromycin and 4% who received azithromycin plus metronidazole discontinued therapy due to clinical side effects.
Clinical adverse reactions leading to discontinuations from these studies were gastrointestinal (abdominal pain, nausea, vomiting, diarrhea), and rashes; laboratory side effects leading to discontinuation were increases in transaminase levels and/or alkaline phosphatase levels.
Overall, the most common adverse reactions associated with treatment in adult patients who received IV/Oral ZITHROMAX in studies of community-acquired pneumonia were related to the gastrointestinal system with diarrhea/loose stools (4.3%), nausea (3.9%), abdominal pain (2.7%), and vomiting (1.4%) being the most frequently reported.
Approximately 12% of patients experienced a side effect related to the intravenous infusion; most common were pain at the injection site (6.5%) and local inflammation (3.1%).
The most common adverse reactions associated with treatment in adult women who received IV/Oral ZITHROMAX in trials of pelvic inflammatory disease were related to the gastrointestinal system. Diarrhea (8.5%) and nausea (6.6%) were most commonly reported, followed by vaginitis (2.8%), abdominal pain (1.9%), anorexia (1.9%), rash and pruritus (1.9%). When azithromycin was coadministered with metronidazole in these trials, a higher proportion of women experienced adverse reactions of nausea (10.3%), abdominal pain (3.7%), vomiting (2.8%), infusion site reaction, stomatitis, dizziness, or dyspnea (all at 1.9%).
Adverse reactions that occurred with a frequency of 1% or less included the following:
Nervous system: Headache, somnolence.
Special senses: Taste perversion.
The following adverse reactions have been identified during post-approval use of azithromycin. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure.
Adverse reactions reported with azithromycin during the post-marketing period in adult and/or pediatric patients for which a causal relationship may not be established include:
Psychiatric: Aggressive reaction and anxiety.
Significant abnormalities (irrespective of drug relationship) occurring during the clinical trials were reported as follows:
- elevated ALT (SGPT), AST (SGOT), creatinine (4 to 6%)
- elevated LDH, bilirubin (1 to 3%)
- leukopenia, neutropenia, decreased platelet count, and elevated serum alkaline phosphatase (less than 1%)
When follow-up was provided, changes in laboratory tests appeared to be reversible.
In multiple-dose clinical trials involving more than 750 patients treated with ZITHROMAX (IV/Oral), less than 2% of patients discontinued azithromycin therapy because of treatment-related liver enzyme abnormalities.
Read the entire FDA prescribing information for Zithromax Injection (Azithromycin)
© Zithromax Injection Patient Information is supplied by Cerner Multum, Inc. and Zithromax Injection Consumer information is supplied by First Databank, Inc., used under license and subject to their respective copyrights.