Medically reviewed by Drugs.com. Last updated on Mar 23, 2022.
The Zmax brand name has been discontinued in the U.S. If generic versions of this product have been approved by the FDA, there may be generic equivalents available.
Commonly used brand name(s)
In the U.S.
- Zithromax Tri-Pak
- Zithromax Z-Pak
Available Dosage Forms:
- Powder for Suspension, Extended Release
- Powder for Suspension
Therapeutic Class: Antibiotic
Chemical Class: Macrolide
Uses for Zmax
Azithromycin is used to treat certain bacterial infections in many different parts of the body. This medicine may mask or delay the symptoms of syphilis. It is not effective against syphilis infections.
Azithromycin belongs to the class of drugs known as macrolide antibiotics. It works by killing bacteria or preventing their growth. However, this medicine will not work for colds, flu, or other virus infections.
This medicine is available only with your doctor's prescription.
Before using Zmax
In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For this medicine, the following should be considered:
Tell your doctor if you have ever had any unusual or allergic reaction to this medicine or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.
Appropriate studies have not been performed on the relationship of age to the effects of azithromycin to treat sinusitis in children or to treat pneumonia in children younger than 6 months of age. Safety and efficacy have not been established.
Appropriate studies have not been performed on the relationship of age to the effects of azithromycin oral suspension and tablets to treat pharyngitis or tonsillitis in children younger than 2 years of age. Safety and efficacy have not been established.
Appropriate studies performed to date have not demonstrated geriatric-specific problems that would limit the usefulness of azithromycin in the elderly. However, elderly patients are more likely to have heart rhythm problems (eg, torsades de pointes) which may require caution in patients receiving azithromycin.
There are no adequate studies in women for determining infant risk when using this medication during breastfeeding. Weigh the potential benefits against the potential risks before taking this medication while breastfeeding.
Interactions with medicines
Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking this medicine, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.
Using this medicine with any of the following medicines is not recommended. Your doctor may decide not to treat you with this medication or change some of the other medicines you take.
- Ergoloid Mesylates
Using this medicine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.
- Aripiprazole Lauroxil
- Arsenic Trioxide
- Cholera Vaccine, Live
- Doxorubicin Hydrochloride Liposome
- Inotuzumab Ozogamicin
- Morphine Sulfate Liposome
- Sodium Phosphate
- Sodium Phosphate, Dibasic
- Sodium Phosphate, Monobasic
Using this medicine with any of the following medicines may cause an increased risk of certain side effects, but using both drugs may be the best treatment for you. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.
Interactions with food/tobacco/alcohol
Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. Discuss with your healthcare professional the use of your medicine with food, alcohol, or tobacco.
Other medical problems
The presence of other medical problems may affect the use of this medicine. Make sure you tell your doctor if you have any other medical problems, especially:
- Allergy to any macrolide and ketolide antibiotic (eg, clarithromycin, erythromycin, telithromycin, Biaxin®, Ery-tab®, or Ketek®) or
- Liver disease with prior azithromycin use, history of—Should not be used in patients with this condition.
- Bacteremia (blood infection) or
- Cystic fibrosis or
- Infections, nosocomial or hospital-acquired or
- Weak immune system or
- Weakened physical condition—Should not be used in patients with these conditions to treat pneumonia.
- Bradycardia (slow heartbeat) or
- Congestive heart failure or
- Diarrhea or
- Heart disease or
- Heart rhythm problems (eg, QT prolongation, torsades de pointes, bradyarrhythmias), history of or
- Hypokalemia (low potassium in the blood), uncorrected or
- Hypomagnesemia (low magnesium in the blood), uncorrected or
- Myasthenia gravis (severe muscle weakness)—Use with caution. May make these conditions worse.
- Kidney disease, severe or
- Liver disease—Use with caution. The effects may be increased because of slower removal of the medicine from the body.
Proper use of Zmax
This section provides information on the proper use of a number of products that contain azithromycin. It may not be specific to Zmax. Please read with care.
Take this medicine only as directed by your doctor. Do not take more of it, do not take it more often, and do not take it for a longer time than your doctor ordered.
This medicine comes with a patient information leaflet. Read and follow the instructions carefully. Ask your doctor if you have any questions.
You may take Zithromax® oral liquid or tablets with or without food.
Shake well the bottle of Zithromax® oral liquid before each use. Measure your dose correctly with a marked measuring spoon, oral syringe, or medicine cup. The average household teaspoon may not hold the right amount of liquid.
Measure the Zmax® extended-release oral suspension with a marked measuring spoon, syringe, or cup. You or your child must take this medicine within 12 hours after it has been mixed with water. It is best to take the Zmax® extended-release oral suspension on an empty stomach or at least 1 hour before or 2 hours after a meal. If your child does not use all of the medicine in the bottle, throw it away after you give the dose.
If you or your child vomits within one hour of taking the Zmax® extended-release oral suspension, call your doctor right away to see if more medicine is needed.
Keep using this medicine for the full treatment time, even if you or your child feel better after the first few doses. Your infection may not clear up if you stop using the medicine too soon.
If you are taking aluminum or magnesium-containing antacids, do not take them at the same time that you take Zithromax®. These medicines may keep azithromycin from working properly. However, you can take antacids with Zmax®.
The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.
The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.
- For oral dosage form (extended-release suspension):
- For treatment of pneumonia:
- Adults—2 grams (g) once as a single dose.
- Children weighing 34 kilograms (kg) or more—Dose is based on body weight and must be determined by your doctor. The dose is usually 2 grams once a day, taken as a single dose.
- Children 6 months of age and older weighing less than 34 kg—Dose is based on body weight and must be determined by your doctor. The dose is usually 60 milligrams (mg) per kilogram (kg) of body weight once a day, taken as a single dose.
- For treatment of sinusitis:
- Adults—2 grams (g) once a day as a single dose.
- Children—Use and dose must be determined by your doctor.
- For treatment of pneumonia:
- For oral dosage forms (suspension or tablets):
- For treatment of infections:
- Adults—500 to 2000 milligrams (mg) once a day, taken as a single dose. Depending on the type of infection, this may be followed with doses of 250 to 500 mg once a day for several days.
- Children 6 months of age and older—Dose is based on body weight and must be determined by your doctor. The dose is usually 10 to 30 milligrams (mg) per kilogram (kg) of body weight once a day, taken as a single dose. Depending on the type of infection, this may be followed with doses of 5 to 10 mg per kg of body weight once a day for several days.
- Children younger than 6 months of age—Use and dose must be determined by your doctor.
- For treatment of pharyngitis or tonsillitis:
- Adults—500 milligrams (mg) on Day 1 (the first day), taken as a single dose. Then, 250 mg on Day 2 through Day 5.
- Children 2 years of age and older—Dose is based on body weight and must be determined by your doctor. The dose is usually 12 milligrams (mg) per kilogram (kg) of body weight once a day for 5 days.
- Children younger than 2 years of age—Use and dose must be determined by your doctor.
- For treatment of infections:
If you miss a dose of this medicine, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.
Keep out of the reach of children.
Do not keep outdated medicine or medicine no longer needed.
Ask your healthcare professional how you should dispose of any medicine you do not use.
Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. Keep from freezing.
Do not refrigerate or freeze the Zmax® extended-release oral suspension. After water has been added to the powder, use the dose within 12 hours and throw away any unused liquid after your dose.
You may store the Zithromax® oral liquid at room temperature or in the refrigerator. Do not freeze the bottle. Do not keep the oral liquid for more than 10 days. Throw away any unused liquid after all doses are completed.
Precautions while using Zmax
It is very important that your doctor check the progress of you or your child at regular visits to make sure this medicine is working properly. Blood and urine tests may be needed to check for unwanted effects.
If you or your child's symptoms do not improve within a few days, or if they become worse, check with your doctor.
This medicine may cause serious allergic reactions, including anaphylaxis and angioedema, which can be life-threatening and require immediate medical attention. Call your doctor right away if you or your child have a rash, itching, hives, hoarseness, trouble breathing, trouble swallowing, or any swelling of your hands, face, or mouth after you take this medicine.
Serious skin reactions, including Stevens-Johnson syndrome, acute generalized exanthematous pustulosis, toxic epidermal necrolysis, and drug reaction with eosinophilia and systemic symptoms (DRESS) can occur with this medicine. Check with your doctor right away if you or your child have black, tarry stools, blistering, peeling, or loosening of the skin, chest pain, chills, cough, diarrhea, itching, joint or muscle pain, painful or difficult urination, red irritated eyes, red skin lesions, often with a purple center, sore throat, sores, ulcers, or white spots in the mouth or on the lips, swollen glands, unusual bleeding or bruising or unusual tiredness or weakness while you are using this medicine.
Check with your doctor right away if you or your child have pain or tenderness in the upper stomach, pale stools, dark urine, loss of appetite, nausea, unusual tiredness or weakness, or yellow eyes or skin. These could be symptoms of a serious liver problem.
Call your child's doctor right away if your child feels irritable or vomits after feeding. These may be symptoms of a condition called infantile hypertrophic pyloric stenosis.
Azithromycin may cause diarrhea, and in some cases it can be severe. It may occur 2 months or more after you stop using this medicine. Do not take any medicine to treat diarrhea without first checking with your doctor. Diarrhea medicines may make the diarrhea worse or make it last longer. If you or your child have any questions about this or if mild diarrhea continues or gets worse, check with your doctor.
This medicine can cause changes in heart rhythms, including QT prolongation. It may change the way your heart beats and cause fainting or serious side effects in some patients. Contact your doctor right away if you or your child have any symptoms of heart rhythm problems, including fast, pounding, or irregular heartbeats.
This medicine may increase the risk of serious heart or blood vessel problems. Call your doctor right away if you have blurred vision, chest pain, confusion, lightheadedness, dizziness, fainting, fast or irregular heartbeat, trouble breathing, or unusual tiredness or weakness.
Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal or vitamin supplements.
Zmax side effects
Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.
Check with your doctor immediately if any of the following side effects occur:
- loose stools
- Blistering, crusting, irritation, itching, or reddening of the skin
- cracked, dry, or scaly skin
- Blistering, peeling, or loosening of the skin
- bloody or cloudy urine
- bloody, black, or tarry stools
- body aches or pain
- burning while urinating
- chest pain or tightness
- cough increased
- cough producing mucus
- dark urine
- difficult or labored breathing
- difficult or painful urination
- dryness or soreness of the throat
- fast, irregular, pounding, or racing heartbeat or pulse
- general feeling of discomfort or illness
- irregular or slow heart rate
- itching or rash
- joint or muscle pain
- large, hive-like swelling on the face, eyelids, lips, tongue, throat, hands, legs, feet, or sex organs
- light-colored stools
- loss of appetite
- muscle aches and pains
- nausea or vomiting
- noisy breathing
- passing of gas
- red skin lesions, often with a purple center
- red, irritated eyes
- redness or swelling in the ear
- runny nose
- sores, ulcers, or white spots on the lips or in the mouth
- stomach pain, continuing
- stomach pain, fullness, or discomfort
- stuffy nose
- swelling of the face, ankles, hands, feet, or lower legs
- tender, swollen glands in the neck
- trouble with sleeping
- trouble with swallowing
- unpleasant breath odor
- unusual bleeding or bruising
- unusual tiredness or weakness
- upper right abdominal or stomach pain
- voice changes
- vomiting of blood
- yellow eyes or skin
Incidence not known
- Bleeding gums
- blood in the urine or stools
- blurred vision
- change in hearing
- clay-colored stools
- continuing ringing or buzzing or other unexplained noise in the ears
- decreased urine output
- diarrhea, watery and severe, which may also be bloody
- dizziness, faintness, or lightheadedness when getting up suddenly from a lying or sitting position
- greatly decreased frequency of urination or amount of urine
- increased thirst
- loss of hearing
- lower back or side pain
- muscle twitching
- no blood pressure or pulse
- pains in the stomach, side, or abdomen, possibly radiating to the back
- pale skin
- pinpoint red spots on the skin
- puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue
- rapid weight gain
- stomach cramps or tenderness
- stopping of heart
- unusual weight loss
Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:
- Acid or sour stomach
- aggressive or angry
- bad, unusual, or unpleasant (after) taste
- burning feeling in the chest or stomach
- burning, crawling, itching, numbness, prickling, "pins and needles", or tingling feelings
- change in taste
- changes in the color of the tongue
- dry mouth
- excess air or gas in the stomach or intestines
- feeling of constant movement of self or surroundings
- full feeling
- increase in body movements
- itching of the vagina or genital area
- lack or loss of strength
- mental depression
- pain during sexual intercourse
- quick to react or overreact emotionally
- rapidly changing moods
- rash with flat lesions or small raised lesions on the skin
- redness of the skin
- sensation of spinning
- sleepiness or unusual drowsiness
- stomach upset
- thick, white vaginal discharge with no odor or with a mild odor
- white patches in the mouth, tongue, or throat
Incidence not known
- Difficulty with moving
- increased sensitivity of the skin to sunlight
- muscle pain or stiffness
- pain in the joints
- redness or other discoloration of the skin
- severe sunburn
- trouble sitting still
Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.
Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.
Frequently asked questions
- What antibiotics kill Covid-19 (coronavirus)?
- What are the best antibiotics for a tooth infection?
- How long does azithromycin stay in your system after you finish taking it?
- What are the best antibiotics for pneumonia?
- Does azithromycin cure chlamydia: How much / how long?
- What is the best antibiotic to treat strep throat?
- What antibiotics are used to treat chlamydia and gonorrhea?
More about Zmax (azithromycin)
- Side effects
- Drug interactions
- Dosage information
- During pregnancy or Breastfeeding
- Drug class: macrolides
Related treatment guides
Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.