azithromycin (Rx)

Brand and Other Names:Zithromax
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Dosing & Uses

AdultPediatric

Dosage Forms & Strengths

injection, lyophilized powder for reconstitution

  • 500mg/vial

tablet

  • 250mg
  • 500mg

oral suspension

  • 100mg/5mL
  • 200mg/5mL

Community-acquired Pneumonia

Indicated for treatment of community-acquired pneumonia due to Chlamydophila pneumoniae, Haemophilus influenzae, Mycoplasma pneumoniae, or Streptococcus pneumoniae in patients appropriate for oral therapy

500 mg PO x 1 dose on Day 1, followed by 250 mg PO qDay on Days 2-5

Pharyngitis or Tonsillitis

Indicated for treatment of pharyngitis/tonsillitis caused by Streptococcus pyogenes as an alternative therapy in individuals who cannot use first-line therapy

500 mg PO x 1 dose on Day 1, followed by 250 mg PO qDay on Days 2-5

Uncomplicated skin/skin structure

Indicated for treatment of uncomplicated skin and skin structure infections due to Staphylococcus aureus, Streptococcus pyogenes, or Streptococcus agalactiae

500 mg PO x 1 dose on Day 1, followed by 250 mg PO qDay on Days 2-5

Acute bacterial exacerbations of chronic obstructive pulmonary disease

Indicated for treatment of acute bacterial exacerbations of chronic bronchitis due to Haemophilus influenzae, Moraxella catarrhalis, or Streptococcus pneumoniae

500 mg PO qDay for 3 days OR

Alternatively, 500 mg PO x 1 dose on Day 1, followed by 250 mg PO qDay on Days 2-5

Acute bacterial sinusitis

Indicated for treatment of acute bacterial sinusitis due to Haemophilus influenzae, Moraxella catarrhalis, or Streptococcus pneumoniae

500 mg PO qDay x 3 days

Genital Ulcer Disease (Chancroid)

Indicated for treatment of genital ulcer disease in men due to Haemophilus ducreyi (chancroid)

Efficacy in treatment of chancroid in women has not been established

1000 mg PO x 1 dose

Nongonococcal or Gonococcal Urethritis and Cervicitis

Indicated for treatment of urethritis and cervicitis due to Chlamydia trachomatis or Neisseria gonorrhoeae

1000 mg PO x 1 dose

Pelvic Inflammatory Disease

Indicated for treatment of pelvic inflammatory disease due to Chlamydia trachomatis, Neisseria gonorrhoeae, or Mycoplasma hominis in patients who require initial IV therapy

If anaerobic microorganisms are suspected of contributing to the infection, administer an antimicrobial agent with anaerobic activity in combination with azithromycin

Coronavirus Disease 2019 (COVID-19) (Off-label)

Data available as of March 25, 2020

Note: Limited data available; no drug is FDA approved to treat COVID-19

Azithromycin may be considered for use as part of an investigational protocol for patients with COVID-19

For more information, see the CDC website (link https://www.cdc.gov/coronavirus/2019-ncov/hcp/therapeutic-options.html)

Additional Medscape COVID-19 references are available

Cat Scratch Disease (Off-label)

>45.5 kg: 500 mg PO once, then 250 mg once daily for 4 days

Pertussis (Off-label)

500 mg PO once, then 250 mg once daily for 4 days

Endocarditis (Off-label)

Prophylaxis

500 mg PO 30-60 min before procedure

Current American Heart Association (AHA) guidelines recommend only for high-risk patients

Dosing Considerations

Use only to treat infections that are proven or strongly suspected to be caused by susceptible bacteria in order to reduce the development of drug-resistant bacteria and maintain the effectiveness of azithromycin

Limitations of use

  • Do not use in patients with pneumonia who may be inappropriate for oral therapy because of moderate to severe illness or risk factors such as any of the following:
    • Patients with cystic fibrosis
    • Patients with nosocomial infections
    • Patients with known or suspected bacteremia
    • Patients requiring hospitalization
    • Elderly or debilitated patients
    • Patients with significant underlying health problems that may compromise their ability to respond to their illness (including immunodeficiency or functional asplenia)

Dosage Forms & Strengths

injection, lyophilized powder for reconstitution

  • 500mg/vial

tablet

  • 250mg
  • 500mg

oral suspension

  • 100mg/5mL
  • 200mg/5mL

Acute Otitis Media

Indicated for treatment of acute otitis media in patient >6 months of age caused by Haemophilus influenzae, Moraxella catarrhalis, or Streptococcus pneumoniae

<6 months: Safety and efficacy not established

≥6 months

  • 30 mg/kg PO x 1 dose OR  
  • Alternative dosing
    • 10 mg/kg PO qDay for 3 days OR
    • 10 mg/kg PO x 1 dose on Day 1 followed by 5 mg/kg on Days 2-5

Community-acquired Pneumonia

<6 months: Safety and efficacy not established

≥6 months: 10 mg/kg PO x 1 dose on Day 1, followed by 5 mg/kg PO on Days 2-5  

Pharyngitis/Tonsillitis

Indicated for treatment of pharyngitis/tonsillitis in patients >2 years of age caused by Streptococcus pyogenes as an alternative therapy in individuals who cannot use first-line therapy

<2 years: Safety and efficacy not established

≥2 years: 12 mg/kg PO qDay for 5 days; not to exceed 500 mg/day  

Chlamydia Trachomatis Infection (Off-label)

Treatment of cervicitis or urethritis

Children and adolescents ≥45 kg: 1 g PO as single dose

Cat Scratch Disease (Off-label)

≤45 kg: 10 mg/kg (not to exceed 500 mg/dose) PO as single dose; then 5 mg/kg (not to exceed 250 mg/dose) PO qDay on days 2 through 5

>45 kg: 500 mg PO once, then 250 mg once daily for 4 days

Dosing Considerations

Use only to treat infections that are proven or strongly suspected to be caused by susceptible bacteria in order to reduce the development of drug-resistant bacteria and maintain the effectiveness of azithromycin

Limitations of use

  • Do not use in patients with pneumonia who may be inappropriate for oral therapy because of moderate to severe illness or risk factors such as any of the following:
    • Patients with cystic fibrosis
    • Patients with nosocomial infections
    • Patients with known or suspected bacteremia
    • Patients requiring hospitalization
    • Debilitated patients
    • Patients with significant underlying health problems that may compromise their ability to respond to their illness (including immunodeficiency or functional asplenia)
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Interactions

Interaction Checker

and azithromycin

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    No Interactions Found
    Interactions Found

    Contraindicated

      Serious - Use Alternative

        Significant - Monitor Closely

          Minor

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            Adverse Effects

            >10%

            High single dose therapy

            • Diarrhea (52.8%)
            • Nausea (32.6%)
            • Abdominal pain (27%)
            • Loose stool (19.1%)

            1-10%

            Elevated ALT, AST, creatinine (4-6%)

            Elevated LDH, bilirubin (1-3%)

            Community-acquired pneumonia

            • Pain at injection site (6.5%)
            • Diarrhea (4.3%)
            • Nausea (3.9%)
            • Local inflammation (3.1%)
            • Abdominal pain (2.7%)
            • Vomiting (1.4%)

            Pelvic inflammatory disease

            • Diarrhea (8.5%)
            • Nausea (6.6%)
            • Vaginitis (2.8%)
            • Abdominal pain (1.9%)
            • Anorexia (1.9%)
            • Rash and pruritus (1.9%)

            <1%

            Dyspepsia

            Flatulence

            Mucositis

            Oral Moniliasis

            Gastritis

            Headache

            Somnolence

            Bronchospasm

            Taste perversion

            Leukopenia

            Neutropenia

            Decreased platelet count

            Elevated serum alkaline phosphatase

            Postmarketing Reports

            Allergic: Arthralgia, edema, urticaria and angioedema

            Cardiovascular: Arrhythmias (eg, ventricular tachycardia), hypotension, QT prolongation, and torsades de pointes

            Gastrointestinal: Anorexia, constipation, dyspepsia, flatulence, vomiting/diarrhea, pseudomembranous colitis, pancreatitis, oral candidiasis, pyloric stenosis, and reports of tongue discoloration

            General: Asthenia, paresthesia, fatigue, malaise and anaphylaxis (including fatalities).

            Genitourinary: Interstitial nephritis and acute renal failure and vaginitis

            Hematopoietic: Thrombocytopenia

            Liver/biliary: Abnormal liver function, hepatitis, cholestatic jaundice, hepatic necrosis, and hepatic failure

            Nervous system: Convulsions, dizziness/vertigo, headache, somnolence, hyperactivity, nervousness, agitation and syncope

            Psychiatric: Aggressive reaction and anxiety

            Skin/appendages: Pruritus, serious skin reactions including, erythema multiforme, AGEP, Stevens-Johnson syndrome, toxic epidermal necrolysis, and DRESS

            Special senses: Hearing disturbances including hearing loss, deafness and/or tinnitus and reports of taste/smell perversion and/or loss

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            Warnings

            Contraindications

            Hypersensitivity to azithromycin, erythromycin, any macrolides or ketolides

            History of cholestatic jaundice/hepatic dysfunction associated with prior use of azithromycin

            Cautions

            Abnormal liver function, hepatitis, cholestatic jaundice, hepatic necrosis, and hepatic failure have been reported, some of which have resulted in death; discontinue treatment immediately if signs and symptoms of hepatitis occur

            Infantile Hypertrophic Pyloric Stenosis (IHPS) has been reported; advise direct parents and caregivers if vomiting or irritability with feeding occurs

            Clostridium difficile associated diarrhea (CDAD) has been reported, and may range in severity from mild diarrhea to fatal colitis; if CDAD is suspected or confirmed, discontinue ongoing antibacterial use not directed against C. difficile; institute appropriate fluid and electrolyte management, protein supplementation, antibacterial treatment of C. difficile, and surgical evaluation as clinically indicated

            Exacerbations of symptoms of myasthenia gravis and new onset of myasthenic syndrome have been reported

            Antibacterial agents used to treat nongonococcal urethritis may mask or delay the symptoms of incubating syphilis; all patients with sexually transmitted urethritis or cervicitis should have a serologic test for syphilis and appropriate testing for gonorrhea performed at the time of diagnosis; if infection confirmed, initiate appropriate antibacterial therapy and follow-up tests for these diseases

            Local IV site reactions have been reported with IV azithromycin

            Prescribing azithromycin in the absence of a proven or strongly suspected bacterial infection is unlikely to provide benefit to the patient and increases the risk of the development of drug-resistant bacteria

            QT prolongation

            • Prolonged cardiac repolarization and QT interval, imparting a risk of developing cardiac arrhythmia and torsades de pointes, have been reported with macrolides, including azithromycin
            • Elderly patients may be more susceptible to drug-associated effects on the QT interval
            • Consider the risk of QT prolongation 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 IA (quinidine, procainamide) or Class III (dofetilide, amiodarone, sotalol) antiarrhythmic agents

            Hypersensitivity

            • 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
            • Cases of Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS) have also been reported
            • If an allergic reaction occurs, discontinue drug and institute appropriate therapy
            • Be aware that allergic symptoms may reappear after symptomatic therapy has been discontinued

            Drug interaction overview

            • Coadministration of nelfinavir at steady-state with a single oral dose of azithromycin resulted in increased azithromycin serum concentrations; closely monitor for adverse reactions of azithromycin
            • Spontaneous postmarketing reports suggest that coadministration of azithromycin may potentiate the effects of oral anticoagulants (eg, warfarin), although the prothrombin time was not affected in the dedicated drug interaction study with azithromycin and warfarin; carefully monitor prothrombin time while patients are receiving azithromycin and oral anticoagulants concomitantly
            • Drug interactions with digoxin, colchicine or phenytoin have been observed when combined other macrolide; until further data are developed regarding drug interactions when digoxin, colchicine or phenytoin are used with azithromycin careful monitoring of patients is advised

            Bronchiolitis obliterans

            • August 3, 2018: FDA issues warning letter to healthcare providers
            • Increased relapse and mortality observed with azithromycin in the clinical trial entitled ALLOZITHRO (evaluation of the efficacy of azithromycin to prevent bronchiolitis obliterans syndrome [BOS] after allogenic hematopoietic stem cell transplantation [HSCT])
            • The study was terminated early after an increased risk of relapses was observed in patients taking azithromycin compared with placebo
            • Azithromycin is not indicated for prophylaxis of bronchiolitis obliterans syndrome (BOS) in patients undergoing HSCT and should not be used off-label for this condition
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            Pregnancy & Lactation

            Pregnancy

            Available data on use in pregnant women have not identified any drug-associated risks for major birth defects, miscarriage, or adverse maternal or fetal outcomes

            Animal data

            • 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

            Lactation

            Present in human milk

            Non-serious adverse reactions have been reported in breastfed infants after maternal administration of azithromycin

            No data available on the effects of azithromycin on milk production

            Consider the developmental and health benefits of breastfeeding along with the mother’s clinical need for azithromycin and any potential adverse effects on the breastfed infant from azithromycin or from the underlying maternal condition

            Clinical considerations

            Advise women to monitor the breastfed infant for diarrhea, vomiting, or rash

            Pregnancy Categories

            A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.

            B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.

            C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.

            D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.

            X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.

            NA: Information not available.

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            Pharmacology

            Mechanism of Action

            Binds to 50S ribosomal subunit of susceptible microorganisms and blocks dissociation of peptidyl tRNA from ribosomes, causing RNA-dependent protein synthesis to arrest; does not affect nucleic acid synthesis

            Concentrates in phagocytes and fibroblasts, as demonstrated by in vitro incubation techniques; in vivo studies suggest that concentration in phagocytes may contribute to drug distribution to inflamed tissues

            Absorption

            Absolute bioavailability: 38% (250-mg capsules)

            Peak plasma concentration

            • Oral (3-day regimen): 0.44 mcg/mL (Day 1); 0.54 mcg/mL (Day 3)
            • Oral (5-day regimen): 0.43 mcg/mL (Day 1); 0.24 mcg/mL (Day 5)
            • IV: 1.14 mcg/mL (healthy volunteers); 3.63 mcg/mL (hospitalized patients)

            AUC

            • Oral (3-day regimen): 17.4 mcg⋅hr/mL
            • Oral (5-day regimen): 154.9 mcg⋅hr/mL
            • IV: 8.03 mcg⋅hr/mL (healthy volunteers); 9.6 mcg⋅hr/mL (hospitalized patients)

            Effects of food

            • Oral suspension: When administered with food, peak plasma concentration increased by 56% and AUC unchanged
            • Tablets: No effect

            Distribution

            Protein bound: 51% (0.02 mcg/mL); 7% (2 mcg/mL)

            Elimination

            Clearance: 630 mL/min (single 500-mg oral and IV dose)

            Half-life

            • Oral (3-day regimen): 71.8 hr
            • Oral (5-day regimen): 68.9 hr

            Excretion

            • IV, 1st dose: 11%
            • IV, 5th dose: 14%
            • Oral: 6% (unchanged)
            • Biliary excretion is a major route of elimination for unchanged drug, following oral administration
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            Administration

            IV Incompatibilities

            Y-site: Amikacin, aztreonam, cefotaxime, ceftazidime, ceftriaxone, cefuroxime, ciprofloxacin, clindamycin, droperidol, famotidine, fentanyl, furosemide, gentamicin, imipenem, cilastatin, ketorolac, levofloxacin, morphine, piperacillin-tazobactam, ondansetron(?), potassium chloride, ticarcillin-clavulanate, tobramycin

            Other IV substances, additives, or medications should not be added to azithromycin, or infused simultaneously through the same IV line

            IV Compatibilities

            0.9% NaCl

            0.45% NaCl)

            Dextrose 5% in Water (D5W)

            Lactated Ringer Solution (LR)

            D5W in 0.45% NaCl with 20 mEq KCl

            D5W in LR

            D5W in 0.3% NaCl

            D5W in 0.45% NaCl

            Normosol-M in D5W

            Normosol-R in D5W

            IV Preparation

            Add 4.8 mL of sterile water for injection to 500-mg vial; final concentration is (100 mg/mL); shake vial until all of the drug is dissolved

            Visually inspect vial for particulate matter before administration; discard if particular matter is present

            Dilute reconstituted drug in either a 250-mL (final concentration 2 mg/mL) or 500-mL IV bag (final concentration 1 mg/mL)

            IV Administration

            1 mg/mL diluted solution: Infuse over 3 hr

            2mg/mL diluted solution: Infuse over 1 hr

            Oral Suspension Preparation

            Final concentration after reconstitution is 100 mg/5 mL

            • Add 9 mL of water to 300-mg bottle

            Final concentration after reconstitution is 200 mg/5 mL

            • Add 9 mL of water to 600-mg bottle
            • Add 12 mL of water to 900-mg bottle
            • Add 15 mL of water to 1200-mg bottle

            Oral Administration

            Tablets and oral suspension: Take with or without food

            Oral suspension: Shake well before use; refer to prescribing information for dosing information

            Storage

            Unopened vial: Store at <30ºC (86ºF)

            Reconstituted vial: Store at <30ºC (86ºF) for 24 hr

            Diluted solutions: Store <30ºC (86ºF) for 24 hr OR refrigerate at 5ºC (41ºF)

            Reconstituted oral suspension: Store at 5-30ºC (41-86ºF) and use within 10 days; discard after full dosing is completed

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            Images

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            Formulary

            FormularyPatient Discounts

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            The above information is provided for general informational and educational purposes only. Individual plans may vary and formulary information changes. Contact the applicable plan provider for the most current information.

            Tier Description
            1 This drug is available at the lowest co-pay. Most commonly, these are generic drugs.
            2 This drug is available at a middle level co-pay. Most commonly, these are "preferred" (on formulary) brand drugs.
            3 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs.
            4 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
            5 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
            6 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
            NC NOT COVERED – Drugs that are not covered by the plan.
            Code Definition
            PA Prior Authorization
            Drugs that require prior authorization. This restriction requires that specific clinical criteria be met prior to the approval of the prescription.
            QL Quantity Limits
            Drugs that have quantity limits associated with each prescription. This restriction typically limits the quantity of the drug that will be covered.
            ST Step Therapy
            Drugs that have step therapy associated with each prescription. This restriction typically requires that certain criteria be met prior to approval for the prescription.
            OR Other Restrictions
            Drugs that have restrictions other than prior authorization, quantity limits, and step therapy associated with each prescription.
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            Medscape prescription drug monographs are based on FDA-approved labeling information, unless otherwise noted, combined with additional data derived from primary medical literature.