Other
To reduce the development of drug-resistant bacteria and maintain the effectiveness of Zmax and other antibacterial drugs, Zmax should be used only to treat infections that are proven or strongly suspected to be caused by susceptible bacteria.
Adults:
The data described below reflect exposure to Zmax in 728 adult patients. All patients received a single 2 g oral dose of Zmax. The population studied had community-acquired pneumonia and acute bacterial sinusitis.
In controlled clinical trials with Zmax, the majority of the reported treatment-related adverse reactions were gastrointestinal in nature and mild to moderate in severity.
Overall, the most common treatment-related adverse reactions in adult patients receiving a single 2 g dose of Zmax were diarrhea/loose stools (12%), nausea (4%), abdominal pain (3%), headache (1%), and vomiting (1%). The incidence of treatment-related gastrointestinal adverse reactions was 17% for Zmax and 10% for pooled comparators.
Treatment-related adverse reactions following Zmax treatment that occurred with a frequency of <1% included the following:
Cardiovascular: palpitations, chest pain
Gastrointestinal: constipation, dyspepsia, flatulence, gastritis, oral moniliasis
Genitourinary: vaginitis
Nervous System: dizziness, vertigo
General: asthenia
Allergic: rash, pruritus, urticaria
Special Senses: taste perversion
Laboratory Abnormalities
In subjects with normal baseline values, the following clinically significant laboratory abnormalities (irrespective of drug relationship) were reported in Zmax clinical trials:
- -with an incidence of greater than or equal to 1%: reduced lymphocytes and increased eosinophils; reduced bicarbonate;
- -with an incidence of less than 1%: leukopenia, neutropenia, elevated bilirubin, AST, ALT, BUN, creatinine, alterations in potassium.
- -with an incidence of greater than or equal to 1%: elevated eosinophils, BUN, and potassium; decreased lymphocytes; and alterations in neutrophils;
- -with an incidence of less than 1%: elevated SGOT, SGPT and creatinine; decreased potassium; and alterations in sodium and glucose.
Where follow-up was provided, changes in laboratory tests appeared to be reversible.
Pediatric Patients:
The data described below reflect exposure to Zmax in 907 pediatric patients. The population was 3 months to 12 years of age. All patients received a single 60 mg/kg oral dose of Zmax.
As in adults, the most common treatment-related adverse reactions in pediatric subjects were gastrointestinal in nature. The pediatric subjects all received a single 60 mg/kg dose (equivalent to 27 mg/lb) of Zmax.
In a study with 450 pediatric subjects (ages 3 months to 48 months), vomiting (11%), diarrhea (10%) loose stools (9%), and abdominal pain (2%) were the most frequently reported treatment-related gastrointestinal adverse reactions. Many treatment related gastrointestinal adverse reactions with an incidence greater than 1% began on the day of dosing in these subjects [43% (68/160)] and most [53% (84/160)] resolved within 48 hours of onset. Treatment-related adverse events that were not gastrointestinal, occurring with a frequency ≥ 1% were: rash (5%), anorexia (2%), fever (2%), and dermatitis (2%).
In a second study of 337 pediatric subjects, ages 2 years to 12 years, the most frequently reported treatment-related adverse reactions also included vomiting (14%), diarrhea (7%), loose stools (2%), nausea (4%) and abdominal pain (4%).
A third study investigated the tolerability of two different concentrations of azithromycin oral suspension in 120 pediatric subjects (ages 3 months to 48 months), all of whom were treated with azithromycin. The study evaluated the hypothesis that a more dilute, less viscous formulation (the recommended 27 mg/mL concentration of Zmax) is less likely to induce vomiting in young children than a more concentrated suspension used in other pediatric studies. The vomiting rate for subjects taking the dilute concentration azithromycin was 3% (2/61). The rate was numerically lower but not statistically different from the vomiting for the more concentrated suspension Across both treatment arms, the only treatment-related adverse events with a frequency of ≥ 1% were vomiting (6%, 7/120) and diarrhea (2%, 2/120).
Treatment-related adverse reactions with a frequency of < 1% following Zmax treatment in all 907 pediatric subjects in the Phase 3 studies were:
Body as a whole: chills, fever, flu syndrome, headache;
Digestive: abnormal stools, constipation, dyspepsia, flatulence, gastritis, gastrointestinal disorder, hepatitis;
Hemic and Lymphatic: leukopenia;
Nervous System: agitation, emotional liability, hostility, hyperkinesia, insomnia, irritability, parasthesia, somnolence;
Respiratory: asthma, bronchitis, cough increased, dyspnea, pharyngitis, rhinitis;
Skin and Appendages: dermatitis, fungal dermatitis, maculopapular rash, pruritus, urticaria;
Special Senses: otitis media, taste perversion;
Urogenital: dysuria.
Laboratory Abnormalities
In subjects with normal baseline values, the following clinically significant laboratory abnormalities (irrespective of drug relationship) were reported in Zmax pediatric clinical trials:
Warfarin
Although, in a study of 22 healthy men, a 5-day course of azithromycin did not affect the prothrombin time from a subsequently administered dose of warfarin, spontaneous post-marketing reports suggest that concomitant administration of azithromycin may potentiate the effects of oral anticoagulants. Prothrombin times should be carefully monitored while patients are receiving azithromycin and oral anticoagulants concomitantly.
Community-Acquired Pneumonia: The safety and effectiveness of Zmax have been established in pediatric patients 6 months of age or older with community-acquired pneumonia due to Chlamydophila pneumoniae, Mycoplasma pneumoniae, Haemophilus influenzae or Streptococcus pneumoniae. Use of Zmax for these patients is supported by evidence from adequate and well-controlled studies of Zmax in adults with additional safety and pharmacokinetic data in pediatric patients. [See DOSAGE AND ADMINISTRATION (2.2), ADVERSE REACTIONS (6), CLINICAL PHARMACOLOGY (12.3)]
Acute bacterial sinusitis: Safety and effectiveness in the treatment of pediatric patients with acute bacterial sinusitis have not been established.
Absorption
The bioavailability of Zmax relative to azithromycin immediate release (IR) (powder for oral suspension) was 83%. On average, peak serum concentrations were achieved approximately 2.5 hours later following Zmax administration and were lower by 57%, compared to 2 g azithromycin IR. Thus, single 2 g doses of Zmax and azithromycin IR are not bioequivalent and are not interchangeable.
Effect of food on absorption: A high-fat meal increased the rate and extent of absorption of a 2 g dose of Zmax (115% increase in Cmax, and 23% increase in AUC0–72) compared to the fasted state. A standard meal also increased the rate of absorption (119% increase in Cmax) and with less effect on the extent of absorption (12% increase in AUC0–72) compared to administration of a 2 g Zmax dose in the fasted state.
Effect of antacids: Following the administration of Zmax with an aluminum and magnesium hydroxide antacid, the rate and extent of azithromycin absorption were not altered.
Distribution
The serum protein binding of azithromycin is concentration dependent, decreasing from 51% at 0.02 µg/mL to 7% at 2 µg/mL. Following oral administration, azithromycin is widely distributed throughout the body with an apparent steady-state volume of distribution of 31.1 L/kg.
Azithromycin concentrates in fibroblasts, epithelial cells, macrophages, and circulating neutrophils and monocytes. Higher azithromycin concentrations in tissues than in plasma or serum have been observed. White blood cell and lung exposure data in humans following a single 2 g dose of Zmax in adults are shown in Table 3. Following a 2 g single dose of Zmax, azithromycin achieved higher exposure (AUC0–120) in mononuclear leukocytes (MNL) and polymorphonuclear leukocytes (PMNL) than in serum. The azithromycin exposure (AUC0–72) in lung tissue and alveolar cells (AC) was approximately 100 times that in serum; and the exposure in epithelial lining fluid (ELF) was also higher (approximately 2–3 times) than in serum. The clinical significance of this distribution data is unknown.
| A single 2 g dose of Zmax | ||||
| Abbreviation: WBC: white blood cells; MNL: mononuclear leukocytes; PMNL: polymorphonuclear leukocytes; ELF: Epithelial lining fluid | ||||
| WBC | Cmax (µg/mL) | AUC0–24 (µg∙hr/mL) | AUC0–120 (µg∙hr/mL) | Ct=120 Azithromycin concentration at 120 hours after the start of dosing (µg/mL) |
| MNL Data are presented as mean (standard deviation) | 116 (40.2) | 1790 (540) | 4710 (1100) | 16.2 (5.51) |
| PMNL | 146 (66.0) | 2080 (650) | 10000 (2690) | 81.7 (23.3) |
| LUNG | Cmax (µg/mL) | AUC0–24 (µg∙hr/mL) | AUC0–72 (µg∙hr/mL) | |
| ALVEOLAR CELL Cmax and AUC were calculated based on composite profile (n = 4 subjects/time point/formulation). | 669 | 7028 | 20403 | - |
| ELF | 3.2 | 17.6 | 131 | - |
| Cmax (µg/g) | AUC0–24 (µg∙hr/g) | AUC0–72 (µg∙hr/g) | ||
| LUNG TISSUE | 37.9 | 505 | 1693 | - |
Following a regimen of 500 mg of azithromycin tablets on the first day and 250 mg daily for 4 days, only very low concentrations were noted in cerebrospinal fluid (less than 0.01 µg/mL) in the presence of non-inflamed meninges.
Metabolism
In vitro and in vivo studies to assess the metabolism of azithromycin have not been performed.
Excretion
Serum azithromycin concentrations following a single 2 g dose of Zmax declined in a polyphasic pattern with a terminal elimination half-life of 59 hours. The prolonged terminal half-life is thought to be due to a large apparent volume of distribution.
Biliary excretion of azithromycin, predominantly as unchanged drug, is a major route of elimination. Over the course of a week, approximately 6% of the administered dose appears as unchanged drug in urine.
Special Populations
Renal Impairment
Azithromycin pharmacokinetics were investigated in 42 adults (21 to 85 years of age) with varying degrees of renal impairment. Following the oral administration of a single 1.0 g dose of azithromycin (4 × 250 mg capsules), the mean Cmax and AUC0–120 were 5.1% and 4.2% higher, respectively in subjects with GFR 10 to 80 mL/min compared to subjects with normal renal function (GFR >80 mL/min). The mean Cmax and AUC0–120 were 61% and 35% higher, respectively in subjects with GFR <10 mL/min compared to subjects with normal renal function. (See Renal Impairment (8.6).)
Hepatic Impairment
The pharmacokinetics of azithromycin in subjects with hepatic impairment has not been established.
Pediatric Patients
The pharmacokinetics of azithromycin were characterized following a single 60 mg/kg dose of Zmax in pediatric patients aged 3 months to 16 years. Although there was high inter-patient variability in systemic exposure (AUC and Cmax) across the age groups studied, individual azithromycin AUC and Cmax values in pediatric patients were comparable to or higher than those following administration of 2 g Zmax in adults (Table 4). (See Pediatric Use (8.4).)
| Treatment Group | Pharmacokinetic Parameters | |||
| Cmax (µg/mL) | Tmax Median (range) presented only for Tmax (hr) | AUC(0–24) (µg∙hr/mL) | AUC(0–∞) (µg∙hr/mL) | |
| Empty stomach = dosed with Zmax at least 1 hour before or 2 hours after a meal (Groups I–VI) Fed = dosed with Zmax within 5 minutes of consuming an age-appropriate high-fat breakfast (Group VII) | ||||
| Group 1 (N = 6) [3 to 18 months] | 0.74 (0.20) | 3 (3–3) | 6.29 (1.17) | 14.1 (2.16) (n = 3) |
| Group 2 High mean values were driven by 2 subjects with high exposure (N = 6)[>18 to 36 months] | 1.88 | 3 (3–3) | 19.7 | 37.3 (12.9) (n = 5) |
| Group 3 (N = 6) [>36 to 48 months] | 1.23 (0.42) | 3 (3–6) | 12.9 (3.79) | 22.4 (5.96) |
| Group 4 (N = 6) [>48 months to 8 years] | 1.13 (0.34) | 3 (3–6) | 13.0 (4.21) | 22.2 (6.89) |
| Group 5 (N = 6) [>8 to 12 years] | 1.65 (0.38) | 3 (3–6) | 16.0 (4.99) | 30.1 (10.7) |
| Group 6 (N = 6) [>12 to 16 years] | 0.98 (0.35) | 3 (3–6) | 11.0 (4.78) | 21.3 (9.37) |
| Pooled 1–6 (N = 36) [On an empty stomach] | 1.27 (0.53) | 3 (3–6) | 13.1 (5.78) | 25.2 (10.7) (n = 32) |
| Group 7 One subject vomited immediately after dosing and discontinued from the study (N = 7)[Fed; 18 months to 8 years] | 1.41 (0.62) | 3 (1.5–3.1) | 7.43 (3.00) | 18.9 (3.57) (n = 3) |
Gender
The impact of gender on the pharmacokinetics of azithromycin has not been evaluated for Zmax. However, previous studies have demonstrated no significant differences in the disposition of azithromycin between male and female subjects.
Pharmacokinetic Interaction Studies
A drug interaction study was performed with Zmax and antacids. All other drug interaction studies were performed with azithromycin immediate release (IR) formulations (capsules and tablets, doses ranging from 500 to 1200 mg) and other drugs likely to be co-administered. The effects of co-administration of azithromycin on the pharmacokinetics of other drugs are shown in Table 5 and the effects of other drugs on the pharmacokinetics of azithromycin are shown in Table 6.
When used at therapeutic doses, azithromycin IR had a minimal effect on the pharmacokinetics of atorvastatin, carbamazepine, cetirizine, didanosine, efavirenz, fluconazole, indinavir, midazolam, nelfinavir, sildenafil, theophylline (intravenous and oral), triazolam, trimethoprim/sulfamethoxazole or zidovudine (Table 5). Although the drug interaction studies were not conducted with Zmax, similar modest effect as observed with IR formulation are expected since the total exposure to azithromycin is comparable for Zmax and other azithromycin IR regimens. Therefore, no dosage adjustment of drugs listed in Table 5 is recommended when co-administered with Zmax.
Nelfinavir significantly increased the Cmax and AUC of azithromycin following co-administration with azithromycin IR 1200 mg (Table 6). However, no dose adjustment of azithromycin is recommended when Zmax is co-administered with nelfinavir.
Pharmacokinetic and/or pharmacodynamic interactions with the drugs listed below have not been reported in clinical trials with azithromycin; however, no specific drug interaction studies have been performed to evaluate potential drug-drug interaction. Nonetheless, pharmacokinetic and/or pharmacodynamic interactions with these drugs have been observed with other macrolide products. Until further data are developed, careful monitoring of patients is advised when azithromycin and these drugs are used concomitantly: digoxin, ergotamine or dihydroergotamine, cyclosporine, hexobarbital and phenytoin.
| Co-administered Drug | Dose of Co-administered Drug | Dose of Azithromycin Refers to azithromycin capsules and tablets unless specified | n | Ratio (with/without Azithromycin) of Co-administered Drug Pharmacokinetic Parameters (90% CI); No Effect = 1.00 | |
| Mean Cmax | Mean AUC | ||||
| Atorvastatin | 10 mg/day × 8 days | 500 mg/day PO on days 6–8 | 12 | 0.83 (0.63 to 1.08) | 1.01 (0.81 to 1.25) |
| Carbamazepine | 200 mg/day × 2 days, then 200 mg BID × 18 days | 500 mg/day PO for days 16–18 | 7 | 0.97 (0.88 to 1.06) | 0.96 (0.88 to 1.06) |
| Cetirizine | 20 mg/day × 11 days | 500 mg PO on day 7, then 250 mg/day on days 8–11 | 14 | 1.03 (0.93 to 1.14) | 1.02 (0.92 to 1.13) |
| Didanosine | 200 mg PO BID × 21 days | 1,200 mg/day PO on days 8–21 | 6 | 1.44 (0.85 to 2.43) | 1.14 (0.83 to 1.57) |
| Efavirenz | 400 mg/day × 7 days | 600 mg PO on day 7 | 14 | 1.04 90% confidence interval not reported | 0.95 |
| Fluconazole | 200 mg PO single dose | 1,200 mg PO single dose | 18 | 1.04 (0.98 to 1.11) | 1.01 (0.97 to 1.05) |
| Indinavir | 800 mg TID × 5 days | 1,200 mg PO on day 5 | 18 | 0.96 (0.86 to 1.08) | 0.90 (0.81 to 1.00) |
| Midazolam | 15 mg PO on day 3 | 500 mg/day PO × 3 days | 12 | 1.27 (0.89 to 1.81) | 1.26 (1.01 to 1.56) |
| Nelfinavir | 750 mg TID × 11 days | 1,200 mg PO on day 9 | 14 | 0.90 (0.81 to 1.01) | 0.85 (0.78 to 0.93) |
| Sildenafil | 100 mg on days 1 and 4 | 500 mg/day PO × 3 days | 12 | 1.16 (0.86 to 1.57) | 0.92 (0.75 to 1.12) |
| Theophylline | 4 mg/kg IV on days 1, 11, 25 | 500 mg PO on day 7, then 250 mg/day on days 8–11 | 10 | 1.19 (1.02 to 1.40) | 1.02 (0.86 to 1.22) |
| Theophylline | 300 mg PO BID × 15 days | 500 mg PO on day 6, then 250 mg/day on days 7–10 | 8 | 1.09 (0.92 to 1.29) | 1.08 (0.89 to 1.31) |
| Triazolam | 0.125 mg on day 2 | 500 mg PO on day 1, then 250 mg/day on day 2 | 12 | 1.06 | 1.02 |
| Trimethoprim/ Sulfamethoxazole | 160 mg/800 mg/day PO × 7 days | 1,200 mg PO on day 7 | 12 | 0.85 (0.75 to 0.97)/ 0.90 (0.78 to 1.03) | 0.87 (0.80 to 0.95)/ 0.96 (0.88 to 1.03) |
| Zidovudine | 500 mg/day PO × 21 days | 600 mg/day PO × 14 days | 5 | 1.12 (0.42 to 3.02) | 0.94 (0.52 to 1.70) |
| Zidovudine | 500 mg/day PO × 21 days | 1,200 mg/day PO × 14 days | 4 | 1.31 (0.43 to 3.97) | 1.30 (0.69 to 2.43) |
| Co-administered Drug | Dose of Co-administered Drug | Dose of Azithromycin Refers to azithromycin capsules and tablets unless specified | n | Ratio (with/without co-administered drug) of Azithromycin Pharmacokinetic Parameters (90% CI); No Effect = 1.00 | |
| Mean Cmax | Mean AUC | ||||
| Efavirenz | 400 mg/day × 7 days | 600 mg PO on day 7 | 14 | 1.22 (1.04 to 1.42) | 0.92 90% confidence interval not reported |
| Fluconazole | 200 mg PO single dose | 1,200 mg PO single dose | 18 | 0.82 (0.66 to 1.02) | 1.07 (0.94 to 1.22) |
| Nelfinavir | 750 mg TID × 11 days | 1,200 mg PO on day 9 | 14 | 2.36 (1.77 to 3.15) | 2.12 (1.80 to 2.50) |
| Aluminum and Magnesium hydroxide | 20 mL regular strength, single dose | 2 g Zmax, single dose | 39 | 0.99 (0.93 to 1.06) | 0.99 (0.92 to 1.08) |
Spectrum of Activity
Azithromycin has been shown to be active against most isolates of the following microorganisms, both in vitro and in clinical infections as described in the INDICATIONS AND USAGE section.
Aerobic and facultative Gram-positive microorganisms
Streptococcus pneumoniae
NOTE: Erythromycin- and penicillin-resistant Gram-positive isolates may demonstrate cross-resistance to azithromycin.
Aerobic and facultative Gram-negative microorganisms
Haemophilus influenzae
Moraxella catarrhalis
Beta-lactamase production should not affect azithromycin activity.
"Other" microorganisms
Chlamydophila pneumoniae
Mycoplasma pneumoniae
The following in vitro data are available, but their clinical significance is unknown.
At least 90% of the following microorganisms exhibit an in vitro minimum inhibitory concentration (MIC) less than or equal to the azithromycin susceptible breakpoints of <4 µg/mL. However, the safety and effectiveness of azithromycin in treating clinical infections due to these microorganisms have not been established in adequate and well-controlled trials.
Aerobic and facultative Gram-positive microorganisms
Staphylococcus aureus
Streptococcus agalactiae
Streptococcus pyogenes
Streptococci (Groups C, F, G)
Viridans group streptococci
Aerobic and facultative Gram-negative microorganisms
Bordetella pertussis
Legionella pneumophila
Anaerobic microorganisms
Peptostreptococcus species
Prevotella bivia
"Other" microorganisms
Ureaplasma urealyticum
Susceptibility Testing Methods:
When available, the clinical microbiology laboratory should provide cumulative results of in vitro susceptibility test results for antimicrobial drugs used in local hospitals and practice areas to the physician as periodic reports that describe the susceptibility profile of nosocomial and community-acquired pathogens. These reports should aid the physician in selecting the most effective antimicrobial.
Dilution techniques:
Quantitative methods are used to determine antimicrobial minimum inhibitory concentrations (MICs). These MICs provide estimates of the susceptibility of bacteria to antimicrobial compounds. The MICs should be determined using a standardized procedure. Standardized procedures are based on a dilution method1,3 (broth or agar) or equivalent with standardized inoculum concentrations and standardized concentrations of azithromycin powder. The MIC values should be interpreted according to criteria provided in Table 7.
Diffusion techniques:
Quantitative methods that require measurement of zone diameters also provide reproducible estimates of the susceptibility of bacteria to antimicrobial compounds. One such standardized procedure2,3 requires the use of standardized inoculum concentrations. This procedure uses paper disks impregnated with 15-µg azithromycin to test the susceptibility of microorganisms to azithromycin. The disk diffusion interpretive criteria are provided in Table 7.
| Minimum Inhibitory Concentrations (µg/mL) | Disk Diffusion (zone diameters in mm) | |||||
| Pathogen | S | I | R The current absence of data on resistant strains precludes defining any category other than "susceptible." If strains yield MIC results other than susceptible, they should be submitted to a reference laboratory for further testing. | S | I | R |
| Haemophilus influenzae | ≤ 4 | -- | -- | ≥ 12 | -- | -- |
| Streptococcus pneumoniae | ≤ 0.5 | 1 | ≥ 2 | ≥ 18 | 14–17 | ≤ 13 |
No interpretive criteria have been established for testing Moraxella catarrhalis. This species is not usually tested.
A report of "susceptible" indicates that the pathogen is likely to be inhibited if the antimicrobial compound reaches the concentrations usually achievable. A report of "intermediate" indicates that the result should be considered equivocal, and, if the microorganism is not fully susceptible to alternative, clinically feasible drugs, the test should be repeated. This category implies possible clinical applicability in body sites where the drug is physiologically concentrated or in situations where high dosage of drug can be used. This category also provides a buffer zone, which prevents small uncontrolled technical factors from causing major discrepancies in interpretation. A report of "resistant" indicates that the pathogen is not likely to be inhibited if the antimicrobial compound reaches the concentrations usually achievable; other therapy should be selected.
Quality Control:
Standardized susceptibility test procedures require the use of quality control microorganisms to determine if the test was performed correctly. Standard azithromycin powder should provide the range of values noted in Table 8. Quality control (QC) microorganisms are specific strains of organisms with intrinsic biological properties. QC strains are very stable strains, which will give a standard and repeatable susceptibility pattern. The specific strains used for microbiological quality control are not clinically significant.
| QC Strain | Minimum Inhibitory Concentrations (µg/mL) | Disk Diffusion (zone diameters in mm) |
| Haemophilus influenzae ATCC 49247 | 1.0–4.0 | 13–21 |
| Streptococcus pneumoniae ATCC 49619 | 0.06–0.25 | 19–25 |
Acute Bacterial Maxillary Sinusitis
Adult subjects with a diagnosis of acute bacterial maxillary sinusitis were evaluated in a randomized, double-blind, multicenter study; a maxillary sinus tap was performed on all subjects at baseline. Clinical evaluations were conducted for all subjects at the TOC visit, 7 to 14 days post-treatment. Two hundred seventy (270) subjects were treated with a single 2 g oral dose of Zmax and 268 subjects were treated with levofloxacin, 500 mg orally QD for 10 days. A subject was considered a cure if signs and symptoms related to the acute infection had resolved, or if clinical improvement was such that no additional antibiotics were deemed necessary. The clinical response for the primary population, Clinical Per Protocol Subjects, is presented below.
| ZMAX | LEVOFLOXACIN | |
| RESPONSE AT TOC | N = 255 | N = 254 |
| CURE | 241 (94.5%) | 236 (92.9%) |
| FAILURE | 14 (5.5%) | 18 (7.1%) |
Clinical response by pathogen in the Bacteriologic Per Protocol population is presented below.
| Zmax | Levofloxacin | |||
| Pathogen | N | Cure | N | Cure |
| S. pneumoniae | 37 | 36 (97.3%) | 39 | 36 (92.3%) |
| H. influenzae | 27 | 26 (96.3%) | 30 | 30 (100.0%) |
| M. catarrhalis | 8 | 8 (100.0%) | 11 | 10 (90.9%) |
Community-Acquired Pneumonia
Adult subjects with a diagnosis of mild-to-moderate community-acquired pneumonia were evaluated in two, randomized, double-blind, multicenter studies. In both studies, clinical and microbiologic evaluations were conducted for all subjects at the Test of Cure (TOC) visit, 7 to 14 days post-treatment. In the first study, 247 subjects were treated with a single 2 g oral dose of Zmax and 252 subjects were treated with clarithromycin extended release, 1 g orally QD for 7 days. In the second study, 211 subjects were treated with a single 2.0 g oral dose of Zmax and 212 subjects were treated with levofloxacin, 500 mg orally QD for 7 days. A patient was considered a cure if signs and symptoms related to the acute infection had resolved, or if clinical improvement was such that no additional antibiotics were deemed necessary; in addition, the chest x-ray performed at the TOC visit was to be either improved or stable. The clinical response at TOC for the primary population, Clinical Per Protocol Subjects, is presented in the table below.
| ZMAX | COMPARATOR | |
| ZMAX VS. CLARITHROMYCIN EXTENDED RELEASE | N=202 | N=209 |
| CURE | 187 (92.6%) | 198 (94.7%) |
| FAILURE | 15 (7.4%) | 11 (5.3%) |
| ZMAX VS. LEVOFLOXACIN | N=174 | N=189 |
| CURE | 156 (89.7%) | 177 (93.7%) |
| FAILURE | 18 (10.3%) | 12 (6.3%) |
Clinical response by pathogen in the Bacteriologic Per Protocol population, across both studies, is presented below:
| Pathogen | Zmax | Comparators | ||
| N | Cure | N | Cure | |
| S. pneumoniae | 33 | 28 (84.8%) | 39 | 35 (89.7%) |
| H. influenzae | 30 | 28 (93.3%) | 34 | 31 (91.2%) |
| C. pneumoniae | 40 | 37 (92.5%) | 53 | 50 (94.3%) |
| M. pneumoniae | 33 | 30 (90.9%) | 39 | 38 (97.4%) |