Zithromax 500mg Tab Tri-Pak
It is used to treat or prevent bacterial infections.
Drug Class
Antibiotic
Pharmacologic Class
Macrolide antibiotic
Pregnancy Category
Not available
FDA Approved
Nov 1991
DEA Schedule
Not Controlled
Overview
What is this medicine?
Azithromycin is an antibiotic used to treat various bacterial infections, such as respiratory infections, skin infections, and certain sexually transmitted infections. It works by stopping the growth of bacteria.
How to Use This Medicine
Taking Your Medication
To use this medication correctly, follow your doctor's instructions and read all the information provided. You can take this medication with or without food. However, do not take antacids containing magnesium or aluminum at the same time as this medication. If you have any questions, consult your doctor or pharmacist. Continue taking this medication as directed by your doctor or healthcare provider, even if you start feeling well.
Storing and Disposing of Your Medication
Store this medication at room temperature in a dry location, avoiding the bathroom. Keep all medications in a secure place, out of the reach of children and pets. Dispose of unused or expired medications properly. Do not flush them down the toilet or pour them down the drain unless instructed to do so. If you are unsure about the best way to dispose of your medication, consult your pharmacist. You may also want to check if there are drug take-back programs available in your area.
Missing a Dose
If you miss a dose, take it as soon as you remember. However, if it is close to the time for your next scheduled dose, skip the missed dose and resume your regular dosing schedule. Do not take two doses at the same time or take extra doses to make up for the missed one.
To use this medication correctly, follow your doctor's instructions and read all the information provided. You can take this medication with or without food. However, do not take antacids containing magnesium or aluminum at the same time as this medication. If you have any questions, consult your doctor or pharmacist. Continue taking this medication as directed by your doctor or healthcare provider, even if you start feeling well.
Storing and Disposing of Your Medication
Store this medication at room temperature in a dry location, avoiding the bathroom. Keep all medications in a secure place, out of the reach of children and pets. Dispose of unused or expired medications properly. Do not flush them down the toilet or pour them down the drain unless instructed to do so. If you are unsure about the best way to dispose of your medication, consult your pharmacist. You may also want to check if there are drug take-back programs available in your area.
Missing a Dose
If you miss a dose, take it as soon as you remember. However, if it is close to the time for your next scheduled dose, skip the missed dose and resume your regular dosing schedule. Do not take two doses at the same time or take extra doses to make up for the missed one.
Lifestyle & Tips
- Take the medication exactly as prescribed, even if symptoms improve before the full course is finished.
- Do not take antacids containing aluminum or magnesium at the same time as azithromycin; separate by at least 2 hours.
- May be taken with or without food, but taking with food may help reduce stomach upset.
- Avoid excessive sun exposure as azithromycin can increase sensitivity to sunlight.
Available Forms & Alternatives
Available Strengths:
- Zithromax 200mg Sus 15ml(purple Bx)
- Zithromax 100mg Susp 15ml(green Bx)
- Zithromax 200mg Sus 22.5ml(white Bx
- Zithromax 1gm Powder Packet
- Zithromax 200mg Sus 30ml(yellow Bx)
- Zithromax 600mg Tabs
- Zithromax 250mg Tabs (z-Pak)
- Zithromax 500mg Tab Tri-Pak
- Zithromax 500mg Tablets
- Zithromax 500mg Sdv Inj, 1 Vial
- Zithromax 250mg Tablets
Generic Alternatives:
Dosing & Administration
Adult Dosing
Standard Dose:
500 mg orally once daily for 3 days (total 1.5 g) for most infections, or 500 mg as a single dose on Day 1, followed by 250 mg once daily on Days 2-5 (total 1.5 g) for certain infections.
Dose Range:
250 - 2000 mg
Condition-Specific Dosing:
Community-acquired pneumonia:
500 mg as a single dose on Day 1, followed by 250 mg once daily on Days 2-5.
Pharyngitis/Tonsillitis (as alternative to first-line therapy):
500 mg orally once daily for 3 days.
Uncomplicated skin/skin structure infections:
500 mg as a single dose on Day 1, followed by 250 mg once daily on Days 2-5.
Urethritis and Cervicitis (due to Chlamydia trachomatis):
1 g (1000 mg) as a single oral dose.
Genital Ulcer Disease (Chancroid):
1 g (1000 mg) as a single oral dose.
Pediatric Dosing
Neonatal:
Not established for routine use; specific indications (e.g., neonatal conjunctivitis due to Chlamydia) require specific dosing.
Infant:
10 mg/kg orally once daily for 3 days for acute otitis media or pharyngitis/tonsillitis (max 500 mg/day).
Child:
10 mg/kg orally once daily for 3 days for acute otitis media or pharyngitis/tonsillitis (max 500 mg/day); 12 mg/kg orally once daily for 5 days for community-acquired pneumonia (max 500 mg/day).
Adolescent:
Adult dosing applies for most indications.
Dose Adjustments
Renal Impairment:
Mild:
No dosage adjustment necessary.
Moderate:
No dosage adjustment necessary.
Severe:
No dosage adjustment necessary for CrCl >10 mL/min. Caution advised for CrCl <10 mL/min due to limited data.
Dialysis:
Not significantly removed by hemodialysis or peritoneal dialysis. No specific supplemental dose needed.
Hepatic Impairment:
Mild:
No dosage adjustment necessary.
Moderate:
No dosage adjustment necessary.
Severe:
Use with caution; Azithromycin is primarily eliminated by the liver. Avoid use in patients with severe hepatic impairment.
Pharmacology
Mechanism of Action
Azithromycin is a macrolide antibiotic that inhibits bacterial protein synthesis by binding to the 50S ribosomal subunit, thereby blocking the translocation of peptides.
Pharmacokinetics
Absorption:
Bioavailability:
Approximately 37%
Tmax:
2-3 hours
FoodEffect:
Food decreases Cmax by 50% and AUC by 18% for the oral suspension; food effect on tablets is minimal but absorption may be slightly reduced.
Distribution:
Vd:
Extremely large (31.1 L/kg), indicating extensive tissue distribution.
ProteinBinding:
Variable, 7-51% (concentration-dependent)
CnssPenetration:
Limited, but detectable in CSF during meningeal inflammation.
Elimination:
HalfLife:
68 hours (terminal elimination half-life from plasma)
Clearance:
Not available (highly variable due to extensive tissue distribution)
ExcretionRoute:
Primarily biliary (50% unchanged), with a small amount (6-11%) excreted renally.
Unchanged:
Approximately 50% in bile, 6-11% in urine.
Pharmacodynamics
OnsetOfAction:
Rapid, within hours of administration.
PeakEffect:
Not directly applicable as effect is related to tissue concentration and post-antibiotic effect, which persists for days.
DurationOfAction:
Prolonged, due to high tissue penetration and long half-life, allowing for short courses of therapy (e.g., 3-5 days with effects lasting for 7-10 days).
Safety & Warnings
Side Effects
Urgent Side Effects: Seek Medical Help Right Away
Although rare, some people may experience severe and potentially life-threatening side effects while taking this medication. If you notice any of the following symptoms, contact your doctor or seek medical attention immediately:
Signs of an allergic reaction, such as:
+ Rash
+ Hives
+ Itching
+ Red, swollen, blistered, or peeling skin (with or without fever)
+ Wheezing
+ Tightness in the chest or throat
+ Trouble breathing, swallowing, or talking
+ Unusual hoarseness
+ Swelling of the mouth, face, lips, tongue, or throat
Chest pain or pressure
Fast heartbeat or abnormal heartbeat
Dizziness or fainting
Changes in hearing
Fever
Changes in eyesight
Diarrhea, especially if it is severe, bloody, or watery (see below for more information on diarrhea)
Stomach pain, cramps, or very loose stools
Important Information About Diarrhea
Diarrhea is a common side effect of antibiotics. However, in rare cases, a severe form of diarrhea called C. diff-associated diarrhea (CDAD) may occur. This condition can lead to a life-threatening bowel problem. If you experience stomach pain, cramps, or very loose, watery, or bloody stools, contact your doctor right away. Before treating diarrhea, consult with your doctor.
Liver Problems and Severe Skin Reactions
Liver problems, which can be life-threatening, have been reported with this medication. If you experience any of the following symptoms, contact your doctor immediately:
Dark urine
Tiredness
Decreased appetite
Upset stomach or stomach pain
Light-colored stools
Vomiting
Yellow skin or eyes
Severe skin reactions, including Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), and other serious reactions, can also occur. These reactions can affect body organs and be life-threatening. Seek medical help right away if you notice:
Red, swollen, blistered, or peeling skin
Red or irritated eyes
Sores in your mouth, throat, nose, eyes, genitals, or any areas of skin
Fever
Chills
Body aches
Shortness of breath
Swollen glands
Other Side Effects
Like all medications, this drug can cause side effects. Many people experience no side effects or only minor ones. However, if you notice any of the following side effects or any other symptoms that bother you or do not go away, contact your doctor:
Headache
Diarrhea
Stomach pain
Upset stomach
* Vomiting
Reporting Side Effects
If you have questions about side effects or want to report any, contact your doctor. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.
Although rare, some people may experience severe and potentially life-threatening side effects while taking this medication. If you notice any of the following symptoms, contact your doctor or seek medical attention immediately:
Signs of an allergic reaction, such as:
+ Rash
+ Hives
+ Itching
+ Red, swollen, blistered, or peeling skin (with or without fever)
+ Wheezing
+ Tightness in the chest or throat
+ Trouble breathing, swallowing, or talking
+ Unusual hoarseness
+ Swelling of the mouth, face, lips, tongue, or throat
Chest pain or pressure
Fast heartbeat or abnormal heartbeat
Dizziness or fainting
Changes in hearing
Fever
Changes in eyesight
Diarrhea, especially if it is severe, bloody, or watery (see below for more information on diarrhea)
Stomach pain, cramps, or very loose stools
Important Information About Diarrhea
Diarrhea is a common side effect of antibiotics. However, in rare cases, a severe form of diarrhea called C. diff-associated diarrhea (CDAD) may occur. This condition can lead to a life-threatening bowel problem. If you experience stomach pain, cramps, or very loose, watery, or bloody stools, contact your doctor right away. Before treating diarrhea, consult with your doctor.
Liver Problems and Severe Skin Reactions
Liver problems, which can be life-threatening, have been reported with this medication. If you experience any of the following symptoms, contact your doctor immediately:
Dark urine
Tiredness
Decreased appetite
Upset stomach or stomach pain
Light-colored stools
Vomiting
Yellow skin or eyes
Severe skin reactions, including Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), and other serious reactions, can also occur. These reactions can affect body organs and be life-threatening. Seek medical help right away if you notice:
Red, swollen, blistered, or peeling skin
Red or irritated eyes
Sores in your mouth, throat, nose, eyes, genitals, or any areas of skin
Fever
Chills
Body aches
Shortness of breath
Swollen glands
Other Side Effects
Like all medications, this drug can cause side effects. Many people experience no side effects or only minor ones. However, if you notice any of the following side effects or any other symptoms that bother you or do not go away, contact your doctor:
Headache
Diarrhea
Stomach pain
Upset stomach
* Vomiting
Reporting Side Effects
If you have questions about side effects or want to report any, contact your doctor. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.
Seek Immediate Medical Attention If You Experience:
- Severe, watery diarrhea or bloody stools (even weeks after stopping medication)
- Signs of a severe allergic reaction (hives, difficulty breathing, swelling of face/lips/tongue/throat)
- Yellowing of skin or eyes, dark urine, severe stomach pain (signs of liver problems)
- Chest pain, palpitations, or fainting (signs of heart rhythm problems)
- Severe skin rash with blistering and peeling (Stevens-Johnson syndrome, toxic epidermal necrolysis)
Before Using This Medicine
Before Taking This Medication: Important Information to Share with Your Doctor
It is essential to inform your doctor about the following:
Any allergies you have, including allergies to this medication, its components, or other substances. Be sure to describe the allergic reaction and its symptoms.
If you have previously experienced liver problems or jaundice (yellowing of the skin or eyes) while taking this medication.
Certain health conditions, such as:
+ Abnormal heart rhythms, including a prolonged QTc interval on an electrocardiogram (ECG) or other irregular heartbeats.
+ Slow heartbeat or low levels of potassium or magnesium in your blood.
+ Heart failure, also known as a weak heart.
+ A history of torsades de pointes, a specific type of abnormal heartbeat.
If you are taking any medications that can cause abnormal heart rhythms, particularly those that prolong the QT interval. There are many medications that can have this effect, so it is crucial to consult with your doctor or pharmacist if you are unsure.
To ensure your safety, it is vital to provide your doctor and pharmacist with a comprehensive list of:
All prescription and over-the-counter medications you are taking.
Any natural products, vitamins, or supplements you are using.
* Your complete medical history, including any health problems you have or have had in the past.
Before starting, stopping, or changing the dose of any medication, including this one, you must consult with your doctor to confirm that it is safe to do so. This will help prevent potential interactions and ensure the safe use of this medication.
It is essential to inform your doctor about the following:
Any allergies you have, including allergies to this medication, its components, or other substances. Be sure to describe the allergic reaction and its symptoms.
If you have previously experienced liver problems or jaundice (yellowing of the skin or eyes) while taking this medication.
Certain health conditions, such as:
+ Abnormal heart rhythms, including a prolonged QTc interval on an electrocardiogram (ECG) or other irregular heartbeats.
+ Slow heartbeat or low levels of potassium or magnesium in your blood.
+ Heart failure, also known as a weak heart.
+ A history of torsades de pointes, a specific type of abnormal heartbeat.
If you are taking any medications that can cause abnormal heart rhythms, particularly those that prolong the QT interval. There are many medications that can have this effect, so it is crucial to consult with your doctor or pharmacist if you are unsure.
To ensure your safety, it is vital to provide your doctor and pharmacist with a comprehensive list of:
All prescription and over-the-counter medications you are taking.
Any natural products, vitamins, or supplements you are using.
* Your complete medical history, including any health problems you have or have had in the past.
Before starting, stopping, or changing the dose of any medication, including this one, you must consult with your doctor to confirm that it is safe to do so. This will help prevent potential interactions and ensure the safe use of this medication.
Precautions & Cautions
Important Warnings and Cautions for Patients Taking This Medication
It is essential to inform all your healthcare providers, including doctors, nurses, pharmacists, and dentists, that you are taking this medication. Adhere to the prescribed treatment duration, as prolonged use may increase the risk of a second infection.
Severe Heart Rhythm Changes
This medication can cause severe heart rhythm changes, including prolonged QT interval, which can be life-threatening or fatal. If you have any questions or concerns, consult your doctor.
Myasthenia Gravis
If you have myasthenia gravis, discuss your condition with your doctor. Monitor your symptoms closely, and contact your doctor if they worsen. Additionally, be aware that myasthenia gravis symptoms can occur in people without a prior diagnosis. Seek immediate medical attention if you experience new or worsening muscle weakness, difficulty chewing or swallowing, breathing problems, droopy eyelids, or changes in vision, such as blurred vision or double vision.
Special Considerations
If you are 65 years or older, use this medication with caution, as you may be more susceptible to side effects.
Pregnancy and Breastfeeding
If you are pregnant, plan to become pregnant, or are breastfeeding, consult your doctor to discuss the potential benefits and risks to you and your baby.
Newborns
Newborns taking this medication are at risk of developing a severe stomach problem. If your child vomits or becomes irritable during feeding, contact your doctor immediately.
It is essential to inform all your healthcare providers, including doctors, nurses, pharmacists, and dentists, that you are taking this medication. Adhere to the prescribed treatment duration, as prolonged use may increase the risk of a second infection.
Severe Heart Rhythm Changes
This medication can cause severe heart rhythm changes, including prolonged QT interval, which can be life-threatening or fatal. If you have any questions or concerns, consult your doctor.
Myasthenia Gravis
If you have myasthenia gravis, discuss your condition with your doctor. Monitor your symptoms closely, and contact your doctor if they worsen. Additionally, be aware that myasthenia gravis symptoms can occur in people without a prior diagnosis. Seek immediate medical attention if you experience new or worsening muscle weakness, difficulty chewing or swallowing, breathing problems, droopy eyelids, or changes in vision, such as blurred vision or double vision.
Special Considerations
If you are 65 years or older, use this medication with caution, as you may be more susceptible to side effects.
Pregnancy and Breastfeeding
If you are pregnant, plan to become pregnant, or are breastfeeding, consult your doctor to discuss the potential benefits and risks to you and your baby.
Newborns
Newborns taking this medication are at risk of developing a severe stomach problem. If your child vomits or becomes irritable during feeding, contact your doctor immediately.
Overdose Information
Overdose Symptoms:
- Severe nausea
- Vomiting
- Diarrhea
- Reversible hearing loss
What to Do:
In case of suspected overdose, contact a poison control center immediately (e.g., 1-800-222-1222 in the US) or seek emergency medical attention. Treatment is supportive and symptomatic.
Drug Interactions
Major Interactions
- Amiodarone
- Disopyramide
- Dofetilide
- Dronedarone
- Ibutilide
- Pimozide
- Procainamide
- Quinidine
- Sotalol
- Thioridazine
- Warfarin (increased INR/bleeding risk)
Moderate Interactions
- Antacids (aluminum/magnesium-containing)
- Cyclosporine
- Digoxin
- Ergot alkaloids (e.g., Ergotamine, Dihydroergotamine)
- Nelfinavir
- Statins (risk of myopathy/rhabdomyolysis with some, e.g., Simvastatin, Lovastatin)
Monitoring
Baseline Monitoring
Liver function tests (ALT, AST, bilirubin)
Rationale: To assess baseline hepatic function, especially in patients with pre-existing liver disease, as azithromycin is primarily eliminated by the liver.
Timing: Prior to initiation in patients with known hepatic impairment.
Electrocardiogram (ECG)
Rationale: To assess baseline QT interval in patients with known QT prolongation, uncorrected hypokalemia/hypomagnesemia, clinically significant bradycardia, or receiving other QT-prolonging drugs.
Timing: Prior to initiation in high-risk patients.
Routine Monitoring
Clinical response to therapy
Frequency: Daily during treatment, then as clinically indicated.
Target: Resolution of signs and symptoms of infection.
Action Threshold: Lack of improvement or worsening symptoms may indicate treatment failure or resistant organism.
Adverse effects (e.g., GI upset, rash, signs of C. difficile-associated diarrhea)
Frequency: Daily during treatment and for several weeks post-treatment.
Target: Absence of significant adverse effects.
Action Threshold: Presence of severe or persistent adverse effects warrants evaluation and potential discontinuation.
Symptom Monitoring
- Severe or persistent diarrhea (may indicate Clostridioides difficile-associated diarrhea)
- Signs of allergic reaction (rash, itching, swelling, severe dizziness, trouble breathing)
- Signs of liver problems (unusual tiredness, yellowing eyes/skin, dark urine, severe stomach pain/nausea)
- Signs of heart rhythm problems (fast/irregular heartbeat, severe dizziness, fainting)
- Muscle pain or weakness (especially if taking statins)
Special Patient Groups
Pregnancy
Generally considered acceptable for use during pregnancy when clearly needed. Older classification was Pregnancy Category B. Current data suggest low risk of major birth defects or adverse pregnancy outcomes.
Trimester-Specific Risks:
First Trimester:
Low risk, but use only if clearly indicated.
Second Trimester:
Low risk.
Third Trimester:
Low risk.
Lactation
Considered compatible with breastfeeding. Azithromycin is excreted into breast milk in low amounts. Infant exposure is low, and adverse effects in breastfed infants are rare.
Infant Risk:
Low risk. Monitor infant for diarrhea, vomiting, or rash.
Pediatric Use
Widely used in pediatric populations for various bacterial infections. Dosing is weight-based. Safety and efficacy established for specific indications and age groups.
Geriatric Use
No specific dosage adjustment is required based solely on age. However, elderly patients may be more susceptible to QT prolongation and should be monitored for risk factors (e.g., pre-existing cardiac conditions, concomitant QT-prolonging drugs).
Clinical Information
Clinical Pearls
- Azithromycin has a very long tissue half-life, allowing for short courses of therapy (e.g., 3-5 days) with prolonged therapeutic effects.
- It concentrates well in tissues, particularly phagocytes, which contributes to its efficacy against intracellular pathogens.
- Caution should be exercised in patients with known QT prolongation, uncorrected hypokalemia/hypomagnesemia, or those receiving other QT-prolonging drugs due to the risk of Torsades de Pointes.
- Patients should be advised to complete the full course of therapy, even if symptoms improve, to prevent the development of antibiotic resistance.
- Azithromycin can cause C. difficile-associated diarrhea, which can occur during or even several weeks after discontinuation of therapy.
Alternative Therapies
- Clarithromycin (another macrolide)
- Erythromycin (another macrolide)
- Amoxicillin (for respiratory tract infections)
- Doxycycline (for certain STIs, respiratory infections)
- Levofloxacin (for respiratory tract infections, but with broader spectrum and higher resistance risk)
Cost & Coverage
Average Cost:
$15 - $50 per 3-day Tri-Pak (500mg x 3 tablets)
Generic Available:
Yes
Insurance Coverage:
Tier 1 or Tier 2 (preferred generic)
General Drug Facts
If your symptoms or health issues persist or worsen, it is essential to contact your doctor promptly. To ensure safe and effective treatment, never share your medication with others or take someone else's medication. Some medications may come with an additional patient information leaflet, so it is a good idea to consult with your pharmacist. If you have any questions or concerns about this medication, do not hesitate to discuss them with your doctor, nurse, pharmacist, or other healthcare provider. In the event of a suspected overdose, immediately call your local poison control center or seek emergency medical attention. When seeking help, be prepared to provide detailed information about the overdose, including the medication taken, the amount, and the time it occurred.