azithromycin

Azithromycin tablets are a macrolide antibacterial drug indicated for the treatment of patients with mild to moderate infections caused by susceptible strains of the designated microorganisms in the specific conditions listed below. Azithromycin tablets are a macrolide antibacterial indicated for mild to moderate infections caused by designated, susceptible bacteria: Mycobacterial Infections To reduce the development of drug-resistant bacteria and maintain the effectiveness of azithromycin tablets and other antibacterial drugs, azithromycin tablets should be used only to treat or prevent infections that are proven or strongly suspected to be caused by susceptible bacteria. 1.2 Mycobacterial Infections Prophylaxis of Disseminated Mycobacterium avium complex (MAC) Disease Azithromycin tablets, taken alone or in combination with rifabutin at its approved dose, are indicated for the prevention of disseminated MAC disease in persons with advanced HIV infection [see Dosage and Administration ] . Treatment of Disseminated MAC Disease Azithromycin tablets, taken in combination with ethambutol, are indicated for the treatment of disseminated MAC infections in persons with advanced HIV infection [see Use in Specific Populations and Clinical Studies ] . 1.3 Usage To reduce the development of drug-resistant bacteria and maintain the effectiveness of azithromycin tablets and other antibacterial drugs, azithromycin tablets should be used only to treat 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.

2 DOSAGE AND ADMINISTRATION [see Indications and Usage ] Not for pediatric use. For pediatric patients, please refer to the INDICATIONS AND USAGE and DOSAGE AND ADMINISTRATION sections of the prescribing information for azithromycin for oral suspension 100 mg/5 mL and 200 mg/5 mL bottles. Azithromycin tablets may be taken without regard to food. However, increased tolerability has been observed when tablets are taken with food. Mycobacterial Infections 2.2 Mycobacterial Infections Prevention of Disseminated MAC Infections The recommended dose of azithromycin tablets for the prevention of disseminated Mycobacterium avium complex (MAC) disease is: 1200 mg taken once weekly. This dose of azithromycin tablets may be combined with the approved dosage regimen of rifabutin. Treatment of Disseminated MAC Infections Azithromycin tablets should be taken at a daily dose of 600 mg, in combination with ethambutol at the recommended daily dose of 15 mg/kg. Other antimycobacterial drugs that have shown in vitro activity against MAC may be added to the regimen of azithromycin plus ethambutol at the discretion of the physician or health care provider.

12.1 Mechanism of Action Azithromycin is a macrolide antibacterial drug [see Microbiology ] .

The following clinically significant adverse reactions are described elsewhere in labeling: Hypersensitivity [see Warnings and Precautions ] Hepatotoxicity [see Warnings and Precautions ] Infantile Hypertrophic Pyloric Stenosis (IHPS) [see Warnings and Precautions ] QT Prolongation [see Warnings and Precautions ] Cardiovascular Death [see Warnings and Precautions ] Clostridioides difficile -Associated Diarrhea (CDAD) [see Warnings and Precautions ] Exacerbation of Myasthenia Gravis [see Warnings and Precautions ] The most common adverse reactions are diarrhea (5%), nausea (3%), abdominal pain (3%), or vomiting, (no percent given). To report SUSPECTED ADVERSE REACTIONS, contact AvKARE at 1-855-361-3993 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. 6.1 Clinical 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, most of the reported adverse reactions were mild to moderate in severity and were reversible upon discontinuation of the drug. Approximately 0.7% of the patients from the multiple-dose clinical trials discontinued azithromycin therapy because of treatment-related adverse reactions. Serious adverse reactions included angioedema and cholestatic jaundice. Most of the adverse reactions leading to discontinuation were related to the gastrointestinal tract, e.g., nausea, vomiting, diarrhea, or abdominal pain [see Clinical Studies ]. Multiple-dose regimen Overall, the most common adverse reactions in adult patients receiving a multiple-dose regimen of azithromycin were related to the gastrointestinal system with diarrhea/loose stools (5%), nausea (3%), and abdominal pain (3%) being the most frequently reported. No other adverse reactions occurred in patients on the multiple-dose regimen of azithromycin with a frequency greater than 1%. Adverse reactions that occurred with a frequency of 1% or less included the following: Cardiovascular: Palpitations and chest pain. Gastrointestinal: Dyspepsia, flatulence, vomiting, melena, and cholestatic jaundice. Genitourinary: Monilia, vaginitis, and nephritis. Nervous System: Dizziness, headache, vertigo, and somnolence. General: Fatigue. Allergic: Rash, photosensitivity, and angioedema. Chronic therapy with 1200 mg weekly regimen The nature of adverse reactions seen with the 1200 mg weekly dosing regimen for the prevention of Mycobacterium avium infection in severely immunocompromised HIV-infected patients were similar to those seen with short-term dosing regimens [see Clinical Studies ] . Chronic therapy with 600 mg daily regimen combined with ethambutol The nature of adverse reactions seen with the 600 mg daily dosing regimen for the treatment of Mycobacterium avium complex infection in severely immunocompromised HIV-infected patients were similar to those seen with short term dosing regimens. Five percent of patients experienced reversible hearing impairment in the pivotal clinical trial for the treatment of disseminated MAC in patients with AIDS. Hearing impairment has been reported with macrolide antibiotics, especially at higher doses. Other treatment-related adverse reactions occurring in >5% of subjects and seen at any time during a median of 87.5 days of therapy include: abdominal pain (14%), nausea (14%), vomiting (13%), diarrhea (12%), flatulence (5%), headache (5%), and abnormal vision (5%). Discontinuations from treatment due to laboratory abnormalities or adverse reactions considered related to study drug occurred in 8 of 88 (9.1%) of subjects. 6.2 Postmarketing 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 with azithromycin during the postmarketing period in adult and/or pediatric patients for which a causal relationship may not be established include: Allergic: Arthralgia, edema, urticaria, and angioedema. Cardiovascular: Arrhythmias, including ventricular tachycardia, and hypotension. There have been reports of QT prolongation, torsades de pointes, and cardiovascular death. Gastrointestinal: Anorexia, constipation, dyspepsia, flatulence, vomiting/diarrhea pseudomembranous colitis, pancreatitis, oral candidiasis, pyloric stenosis, and tongue discoloration. General: Asthenia, paresthesia, fatigue, malaise, and anaphylaxis. Genitourinary: Interstitial nephritis, acute renal failure, and vaginitis. Hematopoietic: Thrombocytopenia. Liver/Biliary: Abnormal liver function, hepatitis, cholestatic jaundice, hepatic necrosis, and hepatic failure [see Warnings and Precautions ] . Nervous System: Convulsions, dizziness/vertigo, headache, somnolence, hyperactivity, nervousness, agitation, and syncope. Psychiatric: Aggressive reaction and anxiety. Skin/Appendages: Pruritus, and 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. 6.3 Laboratory Abnormalities Significant abnormalities (irrespective of drug relationship) occurring during the clinical trials were reported as follows: With an incidence of 1 to 2%, elevated serum creatine phosphokinase, potassium, ALT (SGPT), GGT, and AST (SGOT). With an incidence of less than 1%, leukopenia, neutropenia, decreased platelet count, elevated serum alkaline phosphatase, bilirubin, BUN, creatinine, blood glucose, LDH, and phosphate. When follow-up was provided, changes in laboratory tests appeared to be reversible. In multiple-dose clinical trials involving more than 3000 patients, 3 patients discontinued therapy because of treatment-related liver enzyme abnormalities and 1 because of a renal function abnormality. In a phase 1 drug interaction study performed in normal volunteers, 1 of 6 subjects given the combination of azithromycin and rifabutin, 1 of 7 given rifabutin alone, and 0 of 6 given azithromycin alone developed a clinically significant neutropenia ( 5% of subjects with normal baseline values in the pivotal trial for treatment of disseminated MAC in severely immunocompromised HIV - infected patients treated with azithromycin 600 mg daily in combination with ethambutol include: a reduction in absolute neutrophils to <50% of the lower limit of normal (10/52, 19%) and an increase to five times the upper limit of normal in alkaline phosphatase (3/35, 9%). These findings in subjects with normal baseline values are similar when compared to all subjects for analyses of neutrophil reductions (22/75, 29%) and elevated alkaline phosphatase (16/80, 20%). Causality of these laboratory abnormalities due to the use of study drug has not been established.

Nelfinavir: Close monitoring for known side effects of azithromycin, such as liver enzyme abnormalities and hearing impairment, is warranted. Warfarin: Use with azithromycin may increase coagulation times; monitor prothrombin time. 7.1 Nelfinavir Coadministration 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 ] . 7.2 Warfarin 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. 7.3 Potential 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.

Pediatric Use: Safety and effectiveness in the treatment of patients under 6 months of age have not been established. Geriatric Use: Elderly patients may be more susceptible to development of torsades de pointes arrhythmias. 8.1 Pregnancy 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 3, 2, and 1 times, respectively, an adult human daily dose of 600 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 3 times an adult human daily dose of 600 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 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 3 (rats) and 2 (mice) times an adult human daily dose of 600 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 approximately equal to an adult human daily dose of 600 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.

Lactation 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 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. Data Azithromycin breastmilk concentrations were measured in 20 women after receiving a single 2 g oral dose of azithromycin during labor. Breastmilk samples collected on days 3 and 6 postpartum as well as 2 and 4 weeks postpartum revealed the presence of azithromycin in breastmilk up to 4 weeks after dosing. In another study, a single dose of azithromycin 500 mg was administered intravenously to 8 women prior to incision for cesarean section. Breastmilk (colostrum) samples obtained between 12 and 48 hours after dosing revealed that azithromycin persisted in breastmilk up to 48 hours. 8.4 Pediatric Use In controlled clinical studies, azithromycin has been administered to pediatric patients ranging in age from 6 months to 12 years. For information regarding the use of azithromycin for oral suspension in the treatment of pediatric patients, [see Indications and Usage and Dosage and Administration ] of the prescribing information for azithromycin for oral suspension, 100 mg/5 mL and 200 mg/5 mL bottles. HIV-Infected Pediatric Patients: The safety and efficacy of azithromycin for the prevention or treatment of MAC in HIV-infected children have not been established. Safety data are available for 72 children 5 months to 18 years of age (mean 7 years) who received azithromycin for treatment of opportunistic infections. The mean duration of therapy was 242 days (range 3 to 2004 days) at doses of 300 mg/day for a mean of 207 days. These patients were treated for a variety of opportunistic infections, including MAC. The adverse reaction were generally similar to that seen in younger patients, except for a higher incidence of adverse reactions relating to the gastrointestinal system and to reversible impairment of hearing [see Dosage and Administration ] .