Zithromax azithromycin dihydrate 500 mg/5mL Injection, Powder, Lyophilized, For Solution
🆔 Identity & classification
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🏷️ RxNorm drug class
This medicine belongs to the Macrolide Antimicrobial class.
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🏭 Manufacturer & labeler
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🩺 Clinical
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Azithromycin may be associated with lower levels of 7 nutrients — worth a chat with your pharmacist, not a cause for alarm.
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🧪 Inactive Ingredients / Excipients
Inactive ingredients, also called excipients, are components of the drug product other than the active ingredient. They may include fillers, dyes, coatings, preservatives, flavors, or other formulation ingredients.
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UNII 2968PHW8QP
A weak organic acid derived from citrus fruits or made through fermentation. It works as a buffer to control pH, a preservative to extend shelf life, and a flavoring agent in medications.
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UNII 55X04QC32I
A strong alkaline chemical used to adjust and maintain the pH balance of liquid medicines. It helps keep the medicine stable and ensures it stays effective during storage.
2 inactive ingredients listed in the exact product block matched to this NDC.
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ingredient classCode="IACT" elements from the exact product block matched by this NDC. Label-section narrative from DailyMed / the openFDA label index is shown separately when available.Inactive ingredient FAQ
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💲 Pricing
A drug doesn't have one price. Each row is a different public payment system, and none is what you'd pay at the counter — that depends on your insurance. The ⓘ on each row explains what it measures.
| Price system | Per mL | Per package |
|---|---|---|
| Retail pharmacies payNADAC · weekly | Not in the retail survey — common for institutional, discontinued, or low-volume packs. | |
| Medicaid paysCMS SDUD · 12 mo | $47.97 | $2,398.72 / 50 ml |
| Medicare drug plans payPart D · Q2 2026 | $6.07 | $303.29 / 50 ml |
| Medicare Part B allowsASP · J0456 | $1.889 / J0456 unit | — |
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🔁 Therapeutic equivalents
| Product | Labeler | Pack | NADAC/unit | TE | Status | Price vs. this |
|---|---|---|---|---|---|---|
| Azithromycin 500 mg 55150-0174-10 | Eugia | 10 vials | $3.527 | AP | Availability likely | — |
| Azithromycin 500 mg/5mL 63323-0398-10 | Fresenius | 10 vials | $3.527 | AP | Availability likely | — |
| Azithromycin monohydrate 500 mg/10mL 70095-0025-02 | Sun | 10 vials | $3.527 | AP | Availability likely | — |
| Azithromycin 500 mg/5mL 70436-0019-82 | Slate | 10 vials | $3.527 | AP | Availability likely | — |
| Azithromycin 500 mg/5mL 70860-0100-10 | Athenex | 10 vials | $3.527 | AP | Availability likely | — |
| Zithromax 500 mg/5mL 00069-0400-10 | Pfizer | 10 vials | — | — | FDA listed | — |
| Zithromax 500 mg/5mLthis 00069-3150-83 | Pfizer | 10 vials | — | — | FDA listed | — |
| Azithromycin 500 mg/5mL 25021-0180-10 | Sagent | 10 vials | — | AP | FDA listed | — |
| Azithromycin 500 mg/5mL 62756-0512-44 | Sun | 10 vials | — | — | FDA listed | — |
| Azithromycin monohydrate 500 mg/10mL 68083-0199-10 | Gland | 10 vials | — | AP | FDA listed | — |
| Azithromycin 500 mg/5mL 70860-0125-66 | Athenex | 10 vials | — | AP | FDA listed | — |
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⏳ Availability & generic status
FDA-approved generic versions are listed, and recent pricing/market data suggests they may be available — see Therapeutic equivalents.
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🗺️ Medicaid utilization & spend
📊 Medicare Part D spend CMS · PART D · 2026 (Q1)
🔬 Reported adverse events (FAERS)
Top reported reactions
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📦 Packaging — all sizes for this product
| Package NDC | Description | Marketing start | Status |
|---|---|---|---|
| 00069-3150-83 You're viewing this | 10 VIAL in 1 CARTON (0069-3150-83) / 5 mL in 1 VIAL (0069-3150-84) | 1997-01-30 | Active |
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| NDC identity (package / product / labeler codes) | ✓ Available |
| Labeler | ✓ Available |
| Product & package description | ✓ Available |
| Marketing category & status | ✓ Available |
| Active ingredient / dosage form / route | ✓ Available |
| FDA label (SPL via DailyMed) | ✓ Available |
| Package photos | — Not published for this NDC No photo available yet for this listing. |
| Inactive ingredients (structured) | ✓ Available |
| NADAC pharmacy acquisition price (CMS) | — Not published for this NDC CMS publishes NADAC only for NDCs reported in its retail-pharmacy survey. |
| Orange Book / therapeutic-equivalence data | — Not published for this NDC Applies only to products approved under an NDA/ANDA; many listings are out of scope. |
| HCPCS J-code billing crosswalk | ✓ Available |
| Medicaid utilization (CMS SDUD) | ✓ Available |
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📄 Full prescribing information FDA SPL
🎯 Indications and Usage ▾
1 INDICATIONS AND USAGE ZITHROMAX is a macrolide antibacterial drug indicated for the treatment of the following infections caused by designated susceptible microorganisms: • Community-acquired pneumonia in adults ( 1.1 ) • Pelvic inflammatory disease in adults ( 1.2 ) To reduce the development of drug-resistant bacteria and maintain the effectiveness of ZITHROMAX and other antibacterial drugs, ZITHROMAX should be used only to treat or prevent infections that are proven or strongly suspected to be caused by susceptible bacteria.
( 1.3 )
1.1Community-Acquired Pneumonia ZITHROMAX is indicated for the treatment of adult patients with community-acquired pneumonia due to the following susceptible microorganisms: Chlamydophila pneumoniae, Haemophilus influenzae, Legionella pneumophila, Moraxella catarrhalis, Mycoplasma pneumoniae, Staphylococcus aureus, or Streptococcus pneumoniae in patients who require initial intravenous therapy.
1.2Pelvic Inflammatory Disease ZITHROMAX is indicated for the treatment of adult patients with pelvic inflammatory disease due to the following susceptible microorganisms: Chlamydia trachomatis, Neisseria gonorrhoeae, or Mycoplasma hominis in patients who require initial intravenous therapy. If anaerobic microorganisms are suspected of contributing to the infection, an antimicrobial agent with anaerobic activity should be administered in combination with ZITHROMAX.
1.3Usage To reduce the development of drug-resistant bacteria and maintain the effectiveness of ZITHROMAX and other antibacterial drugs, ZITHROMAX should be used only to treat or prevent infections that are proven or strongly suspected to be caused by susceptible bacteria. When culture and susceptibility information are available, they should be considered in selecting or modifying antibacterial therapy. In the absence of such data, local epidemiology and susceptibility patterns may contribute to the empiric selection of therapy.
⏱️ Dosage and Administration ▾
2 DOSAGE AND ADMINISTRATION • Recommended Dosage for Community-acquired pneumonia: 500 mg as a single daily dose by the intravenous route for at least two days. ( 2.1 ) • Recommended Dosage for Pelvic inflammatory disease in adults: 500 mg as a single daily dose by the intravenous route for one or two days. ( 2.2 )
2.1Recommended Dosage for Community-Acquired Pneumonia The recommended dosage of ZITHROMAX for injection for the treatment of adult patients with community-acquired pneumonia due to the indicated organisms is 500 mg as a single daily dose by the intravenous route for at least two days. Intravenous therapy should be followed by azithromycin by the oral route at a single, daily dose of 500 mg, administered as two 250 mg tablets to complete a 7- to 10-day course of therapy. The timing of the switch to oral therapy should be done at the discretion of the physician and in accordance with clinical response. [see Indications and Usage (1.1) and Clinical Pharmacology (12.3) ].
2.2Recommended Dosage for Pelvic Inflammatory Disease The recommended dosage of ZITHROMAX for injection for the treatment of adult patients with pelvic inflammatory disease due to the indicated organisms is 500 mg as a single daily dose by the intravenous route for one or two days. Intravenous therapy should be followed by azithromycin by the oral route at a single, daily dose of 250 mg to complete a 7-day course of therapy. The timing of the switch to oral therapy should be done at the discretion of the physician and in accordance with clinical response. [see Indications and Usage (1.2) and Clinical Pharmacology (12.3) ].
2.3Preparation of the Solution for Intravenous Administration The infusate concentration and rate of infusion for ZITHROMAX for injection should be either 1 mg/mL over 3 hr or 2 mg/mL over 1 hr. ZITHROMAX for injection should not be given as a bolus or as an intramuscular injection. ZITHROMAX for injection should be followed by ZITHROMAX by the oral route as required. [see Dosage and Administration (2.1) and (2.2) ] .
Reconstitution Prepare the initial solution of ZITHROMAX for injection by adding 4.8 mL of Sterile Water for Injection to the 500 mg vial, and shaking the vial until all of the drug is dissolved. Since ZITHROMAX for injection is supplied under vacuum, it is recommended that a standard 5 mL (non-automated) syringe be used to ensure that the exact amount of 4.8 mL of Sterile Water is dispensed. Each mL of reconstituted solution contains 100 mg azithromycin.
Reconstituted solution is stable for 24 hr when stored below 30°C (86°F). Parenteral drug products should be inspected visually for particulate matter prior to administration. If particulate matter is evident in reconstituted fluids, the drug solution should be discarded.
Dilute this solution further prior to administration as instructed below. Dilution To provide azithromycin over a concentration range of 1–2 mg/mL, transfer 5 mL of the 100 mg/mL azithromycin solution into the appropriate amount of any of the diluents listed below: Normal Saline (0.9% sodium chloride) 1/2 Normal Saline (0.45% sodium chloride) 5% Dextrose in Water Lactated Ringer's Solution 5% Dextrose in 1/2 Normal Saline (0.45% sodium chloride) with 20 mEq KCl 5% Dextrose in Lactated Ringer's Solution 5% Dextrose in 1/3 Normal Saline (0.3% sodium chloride) 5% Dextrose in 1/2 Normal Saline (0.45% sodium chloride) Normosol ® -M in 5% Dextrose Normosol ® -R in 5% Dextrose Final Infusion Solution Concentration (mg/mL) Amount of Diluent (mL) 1 mg/mL 500 mL 2 mg/mL 250 mL Other intravenous substances, additives, or medications should not be added to ZITHROMAX for injection, or infused simultaneously through the same intravenous line.
Storage When diluted according to the instructions (1 mg/mL to 2 mg/mL), ZITHROMAX for injection is stable for 24 hr at or below room temperature 30°C (86°F), or for 7 days if stored under refrigeration 5°C (41°F).
💊 Dosage Forms and Strengths ▾
3 DOSAGE FORMS AND STRENGTHS ZITHROMAX for injection is supplied as white to off-white lyophilized powder in a single-dose vial equivalent to 500 mg of azithromycin for intravenous administration. ZITHROMAX for injection is supplied as white to off-white lyophilized powder in a single-dose vial equivalent to 500 mg of azithromycin for intravenous administration. ( 3 )
⛔ Contraindications ▾
4 CONTRAINDICATIONS • Patients with known hypersensitivity to azithromycin, erythromycin, any macrolide, or ketolide antibacterial drug. ( 4.1 ) • Patients with a history of cholestatic jaundice/hepatic dysfunction associated with prior use of azithromycin. ( 4.2 )
4.1Hypersensitivity ZITHROMAX is contraindicated in patients with known hypersensitivity to azithromycin, erythromycin, any macrolide or ketolide drugs.
4.2Hepatic Dysfunction ZITHROMAX is contraindicated in patients with a history of cholestatic jaundice/hepatic dysfunction associated with prior use of azithromycin.
⚠️ Warnings and Cautions ▾
5 WARNINGS AND PRECAUTIONS • Serious (including fatal) allergic and skin reactions. Discontinue ZITHROMAX and initiate appropriate therapy if reaction occurs. ( 5.1 ) • Hepatotoxicity: Severe and sometimes fatal, hepatoxicity has been reported.
Discontinue ZITHROMAX immediately if signs and symptoms of hepatitis occur. ( 5.2 ) • Infantile Hypertrophic Pyloric Stenosis (IHPS): Following the use of azithromycin in neonates (treatment up to 42 days of life), IHPS has been reported. Direct parents and caregivers to contact their physician if vomiting or irritability with feeding occurs.
( 5.3 ) • Prolongation of QT interval and cases of torsades de pointes have been reported. This risk which can be fatal should be considered in patients with certain cardiovascular disorders including known QT prolongation or history torsades de pointes, those with proarrhythmic conditions, and with other drugs that prolong the QT interval. ( 5.4 ) • Cardiovascular Death: Some observational studies have shown an approximately two-fold increased short-term potential risk of acute cardiovascular death in adults exposed to azithromycin relative to other antibacterial drugs, including amoxicillin.
Consider balancing this potential risk with treatment benefits when prescribing ZITHROMAX. ( 5.5 ) • Clostridioides difficile -Associated Diarrhea: Evaluate patients if diarrhea occurs. ( 5.6 ) • ZITHROMAX may exacerbate muscle weakness in persons with myasthenia gravis.
( 5.7 )
5.1Hypersensitivity Serious allergic reactions, including angioedema, anaphylaxis, and dermatologic reactions including Acute Generalized Exanthematous Pustulosis (AGEP), Stevens-Johnson Syndrome, and toxic epidermal necrolysis have been reported in patients on azithromycin therapy. [see Contraindications (4.1) ] Fatalities have been reported. Cases of Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS) have also been reported. Despite initially successful symptomatic treatment of the allergic symptoms, when symptomatic therapy was discontinued, the allergic symptoms recurred soon thereafter in some patients without further azithromycin exposure.
These patients required prolonged periods of observation and symptomatic treatment. The relationship of these episodes to the long tissue half-life of azithromycin and subsequent prolonged exposure to antigen is unknown at present. If an allergic reaction occurs, the drug should be discontinued and appropriate therapy should be instituted.
Physicians should be aware that the allergic symptoms may reappear after symptomatic therapy has been discontinued.
5.2Hepatotoxicity Abnormal liver function, hepatitis, cholestatic jaundice, hepatic necrosis, and hepatic failure have been reported, some of which have resulted in death. Discontinue azithromycin immediately if signs and symptoms of hepatitis occur.
5.3Infantile Hypertrophic Pyloric Stenosis (IHPS) Following the use of azithromycin in neonates (treatment up to 42 days of life), IHPS has been reported. Direct parents and caregivers to contact their physician if vomiting or irritability with feeding occurs.
5.4QT Prolongation Prolonged cardiac repolarization and QT interval, imparting a risk of developing cardiac arrhythmia and torsades de pointes, have been seen with treatment with macrolides, including azithromycin. Cases of torsades de pointes have been spontaneously reported during postmarketing surveillance in patients receiving azithromycin. Providers should consider the risk of QT prolongation, which can be fatal when weighing the risks and benefits of azithromycin for at-risk groups including: • patients with known prolongation of the QT interval, a history of torsades de pointes, congenital long QT syndrome, bradyarrhythmias or uncompensated heart failure • patients on drugs known to prolong the QT interval • patients with ongoing proarrhythmic conditions such as uncorrected hypokalemia or hypomagnesemia, clinically significant bradycardia, and in patients receiving Class…
🤒 Adverse Reactions ▾
6 ADVERSE REACTIONS The following clinically significant adverse reactions are described elsewhere in labeling: • Hypersensitivity [see Warnings and Precautions (5.1) ] • Hepatotoxicity [see Warnings and Precautions (5.2) ] • Infantile Hypertrophic Pyloric Stenosis (IHPS) [see Warnings and Precautions (5.3) ] • QT Prolongation [see Warnings and Precautions (5.4) ] • Cardiovascular Death [see Warnings and Precautions (5.5) ] • Clostridioides difficile- Associated Diarrhea (CDAD) [see Warnings and Precautions (5.6) ] • Exacerbation of Myasthenia Gravis [see Warnings and Precautions (5.7) ] Most common adverse reactions are nausea (4%), diarrhea (4%), abdominal pain (3%), or vomiting (1%).
( 6 ) To report SUSPECTED ADVERSE REACTIONS, contact Pfizer Inc. at 1-800-438-1985 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch .
6.1Clinical 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 co-morbid 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 co-administered 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: Gastrointestinal: Dyspepsia, flatulence, mucositis, oral moniliasis, and gastritis. Nervous system: Headache, somnolence.
Allergic: Bronchospasm. Special senses: Taste perversion.
6.2Postmarketing Experience 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 wit…
🔄 Drug Interactions ▾
7 DRUG INTERACTIONS • Nelfinavir: Close monitoring for known adverse reactions of azithromycin, such as liver enzyme abnormalities and hearing impairment, is warranted. ( 7.1 ) • Warfarin: Use with azithromycin may increase coagulation times; monitor prothrombin time. ( 7.2 )
7.1Nelfinavir Co-administration of nelfinavir at steady-state with a single oral dose of azithromycin resulted in increased azithromycin serum concentrations. Although a dose adjustment of azithromycin is not recommended when administered in combination with nelfinavir, close monitoring for known adverse reactions of azithromycin, such as liver enzyme abnormalities and hearing impairment, is warranted. [see Adverse Reactions (6) ]
7.2Warfarin Spontaneous postmarketing reports suggest that concomitant administration of azithromycin may potentiate the effects of oral anticoagulants such as warfarin, although the prothrombin time was not affected in the dedicated drug interaction study with azithromycin and warfarin. Prothrombin times should be carefully monitored while patients are receiving azithromycin and oral anticoagulants concomitantly.
7.3Potential Drug-Drug Interaction with Macrolides Interactions with digoxin, colchicine or phenytoin have not been reported in clinical trials with azithromycin. No specific drug interaction studies have been performed to evaluate potential drug-drug interaction. However, drug interactions have been observed with other macrolide products.
Until further data are developed regarding drug interactions when digoxin, colchicine or phenytoin are used with azithromycin careful monitoring of patients is advised.
👥 Use in Specific Populations ▾
8 USE IN SPECIFIC POPULATIONS • Geriatric use: Elderly patients may be more susceptible to development of torsades de pointes arrhythmias. ( 8.5 )
8.1Pregnancy Risk Summary Available data from published literature and postmarketing experience over several decades with azithromycin use in pregnant women have not identified any drug-associated risks for major birth defects, miscarriage, or adverse maternal or fetal outcomes (see Data ). Developmental toxicity studies with azithromycin in rats, mice, and rabbits showed no drug-induced fetal malformations at doses up to 4, 2, and 2 times, respectively, an adult human daily dose of 500 mg based on body surface area.
Decreased viability and delayed development were observed in the offspring of pregnant rats administered azithromycin from day 6 of pregnancy through weaning at a dose equivalent to 4 times an adult human daily dose of 500 mg based on body surface area (see Data ) . The estimated background risk of major birth defects and miscarriage for the indicated populations is unknown. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes.
In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2 to 4% and 15 to 20%, respectively. Data Human Data Available data from published observational studies, case series, and case reports over several decades do not suggest an increased risk for major birth defects, miscarriage, or adverse maternal or fetal outcomes with azithromycin use in pregnant women. Limitations of these data include the lack of randomization and inability to control for confounders such as underlying maternal disease and maternal use of concomitant medications.
Animal Data Reproductive and developmental toxicology studies have not been conducted using IV administration of azithromycin to animals. Azithromycin administered during the period of organogenesis did not cause fetal malformations in rats and mice at oral doses up to 200 mg/kg/day (moderately maternally toxic). Based on body surface area, this dose is approximately 4 (rats) and 2 (mice) times an adult human daily dose of 500 mg.
In rabbits administered azithromycin at oral doses of 10, 20, and 40 mg/kg/day during organogenesis, reduced maternal body weight and food consumption were observed in all groups; no evidence of fetotoxicity or teratogenicity was observed at these doses, the highest of which is estimated to be 2 times an adult human daily dose of 500 mg based on body surface area. In a pre- and postnatal development study, azithromycin was administered orally to pregnant rats from day 6 of pregnancy until weaning at doses of 50 or 200 mg/kg/day.
Maternal toxicity (reduced food consumption and body weight gain; increased stress at parturition) was observed at the higher dose. Effects in the offspring were noted at 200 mg/kg/day during the postnatal development period (decreased viability, delayed developmental landmarks). These effects were not observed in a pre- and postnatal rat study when up to 200 mg/kg/day of azithromycin was given orally beginning on day 15 of pregnancy until weaning.
8.2Lactation Risk Summary Azithromycin is present in human milk (see Data ) . Non-serious adverse reactions have been reported in breastfed infants after maternal administration of azithromycin (see Clinical Considerations ) . There are no available data on the effects of azithromycin on milk production.
The developmental and health benefits of breastfeeding should be considered along with the mother's clinical need for ZITHROMAX and any potential adverse effects on the breastfed infant from ZITHROMAX or from the underlying maternal condition. Clinical Considerations Advise women to monitor the breastfed infant for diarrhea, vomiting, or rash. Data Azithromycin breastmilk concentrations were measured in 20 women after receiving a single 2 g oral dose of azithromycin during labor.
Breastmilk sample…
🤰 Pregnancy ▾
8.1Pregnancy Risk Summary Available data from published literature and postmarketing experience over several decades with azithromycin use in pregnant women have not identified any drug-associated risks for major birth defects, miscarriage, or adverse maternal or fetal outcomes (see Data ). Developmental toxicity studies with azithromycin in rats, mice, and rabbits showed no drug-induced fetal malformations at doses up to 4, 2, and 2 times, respectively, an adult human daily dose of 500 mg based on body surface area.
Decreased viability and delayed development were observed in the offspring of pregnant rats administered azithromycin from day 6 of pregnancy through weaning at a dose equivalent to 4 times an adult human daily dose of 500 mg based on body surface area (see Data ) . The estimated background risk of major birth defects and miscarriage for the indicated populations is unknown. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes.
In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2 to 4% and 15 to 20%, respectively. Data Human Data Available data from published observational studies, case series, and case reports over several decades do not suggest an increased risk for major birth defects, miscarriage, or adverse maternal or fetal outcomes with azithromycin use in pregnant women. Limitations of these data include the lack of randomization and inability to control for confounders such as underlying maternal disease and maternal use of concomitant medications.
Animal Data Reproductive and developmental toxicology studies have not been conducted using IV administration of azithromycin to animals. Azithromycin administered during the period of organogenesis did not cause fetal malformations in rats and mice at oral doses up to 200 mg/kg/day (moderately maternally toxic). Based on body surface area, this dose is approximately 4 (rats) and 2 (mice) times an adult human daily dose of 500 mg.
In rabbits administered azithromycin at oral doses of 10, 20, and 40 mg/kg/day during organogenesis, reduced maternal body weight and food consumption were observed in all groups; no evidence of fetotoxicity or teratogenicity was observed at these doses, the highest of which is estimated to be 2 times an adult human daily dose of 500 mg based on body surface area. In a pre- and postnatal development study, azithromycin was administered orally to pregnant rats from day 6 of pregnancy until weaning at doses of 50 or 200 mg/kg/day.
Maternal toxicity (reduced food consumption and body weight gain; increased stress at parturition) was observed at the higher dose. Effects in the offspring were noted at 200 mg/kg/day during the postnatal development period (decreased viability, delayed developmental landmarks). These effects were not observed in a pre- and postnatal rat study when up to 200 mg/kg/day of azithromycin was given orally beginning on day 15 of pregnancy until weaning.
🧒 Pediatric Use ▾
8.4Pediatric Use Safety and effectiveness of ZITHROMAX for injection in pediatric patients have not been established.
🧓 Geriatric Use ▾
8.5Geriatric Use Pharmacokinetic studies with intravenous azithromycin have not been performed in older volunteers. Pharmacokinetics of azithromycin following oral administration in older volunteers (65–85 years old) were similar to those in younger volunteers (18–40 years old) for the 5-day therapeutic regimen. In multiple-dose clinical trials of intravenous azithromycin in the treatment of community-acquired pneumonia, 45% of patients (188/414) were at least 65 years of age and 22% of patients (91/414) were at least 75 years of age.
No overall differences in safety were observed between these subjects and younger subjects in terms of adverse reactions, laboratory abnormalities, and discontinuations. Similar decreases in clinical response were noted in azithromycin- and comparator-treated patients with increasing age. ZITHROMAX (azithromycin for injection) contains 114 mg (4.96 mEq) of sodium per vial.
At the usual recommended doses, patients would receive 114 mg (4.96 mEq) of sodium. The geriatric population may respond with a blunted natriuresis to salt loading. The total sodium content from dietary and non-dietary sources may be clinically important with regard to such diseases as congestive heart failure.
Elderly patients may be more susceptible to development of torsades de pointes arrhythmias than younger patients. [see Warnings and Precautions (5.4) ]
🆘 Overdosage ▾
10 OVERDOSAGE Adverse reactions experienced in higher than recommended doses were similar to those seen at normal doses particularly nausea, diarrhea, and vomiting. In the event of overdosage, general symptomatic and supportive measures are indicated as required.
🧬 Clinical Pharmacology ▾
12 CLINICAL PHARMACOLOGY
12.1Mechanism of Action Azithromycin is a macrolide antibacterial drug [see Microbiology (12.4) ]
12.2Pharmacodynamics Based on animal models of infection, the antibacterial activity of azithromycin appears to correlate with the ratio of area under the concentration-time curve to minimum inhibitory concentration (AUC/MIC) for certain pathogens ( S. pneumoniae and S. aureus ). The principal pharmacokinetic/pharmacodynamic parameter best associated with clinical and microbiological cure has not been elucidated in clinical trials with azithromycin. Cardiac Electrophysiology QTc interval prolongation was studied in a randomized, placebo-controlled parallel trial in 116 healthy subjects who received either chloroquine (1,000 mg) alone or in combination with oral azithromycin (500 mg, 1,000 mg, and 1,500 mg once daily).
Co-administration of azithromycin increased the QTc interval in a dose- and concentration- dependent manner. In comparison to chloroquine alone, the maximum mean (95% upper confidence bound) increases in QTcF were 5 (10) ms, 7 (12) ms and 9 (14) ms with the co-administration of 500 mg, 1,000 mg and 1,500 mg azithromycin, respectively. Since the mean C max of azithromycin following a 500 mg IV dose given over 1 hr is higher than the mean C max of azithromycin following the administration of a 1,500 mg oral dose, it is possible that QTc may be prolonged to a greater extent with IV azithromycin at close proximity to a one hour infusion of 500 mg.
12.3Pharmacokinetics In patients hospitalized with community-acquired pneumonia receiving single daily one-hour intravenous infusions for 2 to 5 days of 500 mg azithromycin at a concentration of 2 mg/mL, the mean C max ± S.D. achieved was 3.63 ± 1.60 mcg/mL, while the 24-hour trough level was 0.20 ± 0.15 mcg/mL, and the AUC 24 was 9.60 ± 4.80 mcg∙hr/mL. The mean C max , 24-hour trough and AUC 24 values were 1.14 ± 0.14 mcg/mL, 0.18 ± 0.02 mcg/mL, and 8.03 ±0.86 mcg∙hr/mL, respectively, in normal volunteers receiving a 3-hour intravenous infusion of 500 mg azithromycin at a concentration of 1 mg/mL.
Similar pharmacokinetic values were obtained in patients hospitalized with community-acquired pneumonia who received the same 3-hour dosage regimen for 2–5 days. Table 1. Mean Plasma Concentrations of Azithromycin Over Time After IV Infusion Infusion Concentration, Duration Time after starting the infusion (hr) 0.5 1 2 3 4 6 8 12 24 2 mg/mL, 1 hr 500 mg (2 mg/mL) for 2–5 days in community-acquired pneumonia patients.
2.98±1.12 3.63 ±1.73 0.60 ±0.31 0.40 ±0.23 0.33 ±0.16 0.26 ±0.14 0.27±0.15 0.20 ±0.12 0.20 ±0.15 1 mg/mL, 3 hr 500 mg (1 mg/mL) for 5 days in healthy subjects. 0.91 ±0.13 1.02 ±0.11 1.14 ±0.13 1.13 ±0.16 0.32 ±0.05 0.28 ±0.04 0.27±0.03 0.22 ±0.02 0.18 ±0.02 Comparison of the plasma pharmacokinetic parameters following the 1st and 5th daily doses of 500 mg intravenous azithromycin showed only an 8% increase in C max but a 61% increase in AUC 24 reflecting a threefold rise in C 24 trough levels. Following single-oral doses of 500 mg azithromycin (two 250 mg capsules) to 12 healthy volunteers, C max , trough level, and AUC 24 were reported to be 0.41 mcg/mL, 0.05 mcg/mL, and 2.6 mcg∙hr/mL, respectively.
These oral values are approximately 38%, 83%, and 52% of the values observed following a single 500-mg I.V. 3-hour infusion (C max : 1.08 mcg/mL, trough: 0.06 mcg/mL, and AUC 24 : 5 mcg∙hr/mL). Thus, plasma concentrations are higher following the intravenous regimen throughout the 24-hour interval.
Distribution The serum protein binding of azithromycin is variable in the concentration range approximating human exposure, decreasing from 51% at 0.02 mcg/mL to 7% at 2 mcg/mL. Tissue concentrations have not been obtained following intravenous infusions of azithromycin, but following oral administration in humans azithromycin has been shown to penetrate into tissues, including skin, lung, tonsil, and cervix. Tissue levels were determined following a s…
🧬 Mechanism of Action ▾
12.1Mechanism of Action Azithromycin is a macrolide antibacterial drug [see Microbiology (12.4) ]
📦 How Supplied / Storage and Handling ▾
16 HOW SUPPLIED/STORAGE AND HANDLING ZITHROMAX for injection (azithromycin for injection, USP) is supplied as white to off-white lyophilized powder under a vacuum in a single-dose vial equivalent to 500 mg of azithromycin for intravenous administration. These are packaged as follows: Unit of Sale Concentration NDC 0069-3150-83 500 mg/vial Carton containing 10 single-dose vials Before reconstitution, store vials at or below 30°C (86°F) [see Dosage and Administration (2.3) ] .
📦 Storage and Handling ▾
Storage When diluted according to the instructions (1 mg/mL to 2 mg/mL), ZITHROMAX for injection is stable for 24 hr at or below room temperature 30°C (86°F), or for 7 days if stored under refrigeration 5°C (41°F).
📋 Description ▾
11 DESCRIPTION ZITHROMAX for injection (azithromycin for injection, USP) contains the active ingredient azithromycin, an azalide, a subclass of macrolide antibacterial drug, for intravenous injection. Azithromycin has the chemical name (2R,3S,4R,5R,8R,10R,11R,12S,13S,14R) -13- [(2,6-dideoxy-3- C -methyl-3- O -methyl-α- L-ribo -hexopyranosyl)oxy]-2-ethyl-3,4,10-trihydroxy-3,5,6,8,10,12,14-hepta-methyl- 11- [[3,4,6-trideoxy-3-(dimethylamino)-β- D - xylo -hexopyranosyl]oxy]-1-oxa- 6-azacyclopentadecan-15-one. Azithromycin is derived from erythromycin; however, it differs chemically from erythromycin in that a methyl-substituted nitrogen atom is incorporated into the lactone ring.
Its molecular formula is C 38 H 72 N 2 O 12 , and its molecular weight is 749. Azithromycin has the following structural formula: Azithromycin, as the dihydrate, is a white crystalline powder with a molecular formula of C 38 H 72 N 2 O 12 ∙ 2H 2 O and a molecular weight of 785. ZITHROMAX for injection (azithromycin for injection, USP) consists of azithromycin dihydrate and the following inactive ingredients: anhydrous citric acid and sodium hydroxide.
Sodium hydroxide is added to adjust the pH. ZITHROMAX for injection (azithromycin for injection, USP) is supplied as white to off-white lyophilized powder in a single-dose vial for intravenous administration. Each vial contains azithromycin dihydrate equivalent to 500 mg of azithromycin, 384.6 mg anhydrous citric acid, and sodium hydroxide.
Reconstitution, according to label directions, results in approximately 5 mL of ZITHROMAX for intravenous injection with each mL containing azithromycin dihydrate equivalent to 100 mg of azithromycin, 76.9 mg anhydrous citric acid, and sodium hydroxide. Chemical Structure
💬 Information for Patients ▾
17 PATIENT COUNSELING INFORMATION Allergic Reactions Instruct patients to immediately contact a physician if any signs of an allergic reaction occur. [see Warnings and Precautions (5.1) ] . Vomiting, Irritability, Diarrhea or Rash with Feeding in Infants Direct parents or caregivers to contact their physician if vomiting, irritability, diarrhea or rash with feeding occurs in the infant. [see Warnings and Precautions (5.3) and Use in Specific Population (8.2) ] . Diarrhea Inform patients that diarrhea is a common problem caused by antibacterial drugs which usually ends when the antibacterial is discontinued.
Sometimes after starting treatment with antibacterials, patients can develop watery and bloody stools (with or without stomach cramps and fever) even as late as two or more months after having taken the last dose of the antibacterial. If this occurs, patients should notify their physician as soon as possible. Antibacterial Resistance Patients should be counseled that antibacterial drugs including ZITHROMAX should only be used to treat bacterial infections.
They do not treat viral infections (e.g., the common cold). When ZITHROMAX is prescribed to treat a bacterial infection, patients should be told that although it is common to feel better early in the course of therapy, the medication should be taken exactly as directed. Skipping doses or not completing the full course of therapy may (1) decrease the effectiveness of the immediate treatment and (2) increase the likelihood that bacteria will develop resistance and will not be treatable by ZITHROMAX or other antibacterial drugs in the future.