Azithromycin and clarithromycin

Ototoxicity of Non-aminoglycoside Antibiotics

It is well-known that aminoglycoside antibiotics can cause significant hearing loss and vestibular deficits that have been described in animal studies and in clinical reports. The purpose of this review is to summarize relevant preclinical and clinical publications that discuss the ototoxicity of non-aminoglycoside antibiotics. The major classes of antibiotics other than aminoglycosides that have been associated with hearing loss in animal studies and in patients are discussed in this report. These antibiotics include: capreomycin, a polypeptide antibiotic that has been used to treat patients with drug-resistant tuberculosis, particularly in developing nations; the macrolides, including erythromycin, azithromycin and clarithromycin; and vancomycin. These antibiotics have been associated with ototoxicity, particularly in neonates. It is critical to be aware of the ototoxic potential of these antibiotics since so much attention has been given to the ototoxicity of aminoglycoside antibiotics in the literature.

Emerging therapeutics in the management of COVID-19

The severe acute respiratory syndrome coronavirus 2 (coronavirus disease 2019, COVID-19) pandemic has placed a tremendous burden on healthcare systems globally. Therapeutics for treatment of the virus are extremely inconsistent due to the lack of time evaluating drug efficacy in clinical trials. Currently, there is a deficiency of published literature that comprehensively discusses all therapeutics being considered for the treatment of COVID-19. A review of the literature was performed for articles related to therapeutics and clinical trials in the context of the current COVID-19 pandemic. We used PubMed, Google Scholar, and Clinicaltrials.gov to search for articles relative to the topic of interest. We used the following keywords: "COVID-19", "therapeutics", "clinical trials", "treatment", "FDA", "ICU", "mortality", and "management". In addition, searches through the references of retrieved articles was also performed. In this paper, we have elaborated on the therapeutic strategies that have been hypothesized or trialed to-date, the mechanism of action of each therapeutic, the clinical trials finished or in-process that support the use of each therapeutic, and the adverse effects associated with each therapeutic. Currently, there is no treatment that has been proven to provide significant benefit in reducing morbidity and mortality. There are many clinical trials for numerous different therapeutic agents currently underway. By looking back and measuring successful strategies from previous pandemics in addition to carrying out ongoing research, we provide ourselves with the greatest opportunity to find treatments that are beneficial.

Hypoglycemia after antimicrobial drug prescription for older patients using sulfonylureas

IMPORTANCE

Certain antimicrobial drugs interact with sulfonylureas to increase the risk of hypoglycemia.

OBJECTIVE

To determine the risk of hypoglycemia and associated costs in older patients prescribed glipizide or glyburide who fill a prescription for an antimicrobial drug.

DESIGN, SETTING, AND PARTICIPANTS

This was a retrospective cohort study of Texas Medicare claims from 2006 to 2009 for patients 66 years or older who were prescribed glipizide or glyburide and who also filled a prescription for 1 of the 16 antimicrobials most commonly prescribed for this population.

METHODS

We assessed hypoglycemia events and associated Medicare costs in patients prescribed 1 of 7 antimicrobial agents thought to interact with sulfonylureas, using noninteracting antimicrobials as a comparison. We used a repeated measure logistic regression, controlling for age, sex, ethnicity, Medicaid eligibility, comorbidity, prior emergency department visits for hypoglycemia, prior hospitalizations for any cause, nursing home residence, and indication for the antimicrobial. We estimated odds of hypoglycemia, number needed to harm, deaths during hospitalization for hypoglycemia, and Medicare costs for hypoglycemia treatment.

MAIN OUTCOMES AND MEASURES

Any hospitalization or emergency department visit owing to hypoglycemia within 14 days of antimicrobial exposure.

RESULTS

In multivariable analyses controlling for patient characteristics and indication for antimicrobial drug use, clarithromycin (odds ratio [OR], 3.96 [95% CI, 2.42-6.49]), levofloxacin (OR, 2.60 [95% CI, 2.18-3.10]), sulfamethoxazole-trimethoprim (OR, 2.56 [95% CI, 2.12-3.10]), metronidazole (OR, 2.11 [95% CI, 1.28-3.47]), and ciprofloxacin (OR, 1.62 [95% CI, 1.33-1.97]) were associated with higher rates of hypoglycemia compared with a panel of noninteracting antimicrobials. The number needed to harm ranged from 71 for clarithromycin to 334 for ciprofloxacin. Patient factors associated with hypoglycemia included older age, female sex, black or Hispanic race/ethnicity, higher comorbidity, and prior hypoglycemic episode. In 2009, 28.3% of patients prescribed a sulfonylurea filled a prescription for 1 of these 5 antimicrobials, which were associated with 13.2% of all hypoglycemia events in patients taking sulfonylureas. The treatment of subsequent hypoglycemia adds $30.54 in additional Medicare costs to each prescription of 1 of those 5 antimicrobials given to patients taking sulfonylureas.

CONCLUSIONS AND RELEVANCE

Prescription of interacting antimicrobial drugs to patients on sulfonylureas is very common, and is associated with substantial morbidity and increased costs.

Liposome-encapsulated antibiotics

Encapsulation of certain antibiotics in liposomes can enhance their effect against microorganisms invading cultured cells and in animal models. We describe the incorporation of amikacin, streptomycin, ciprofloxacin, sparfloxacin, and clarithromycin in a variety of liposomes. We delineate the methods used for the evaluation of their efficacy against Mycobacterium avium-intracellulare complex (MAC) infections in macrophages and in the beige mouse model of MAC disease. We also describe the efficacy of pH-sensitive liposomes incorporating sparfloxacin or azithromycin. We summarize studies with other antibiotics, including rifampicin, rifabutin, ethambutol, isoniazid, clofazimine, and enrofloxacin, and their use against MAC, as well as other infection models, including Mycobacterium tuberculosis.

Is azithromycin the first-choice macrolide for treatment of community-acquired pneumonia?

Combination treatment with a beta-lactam plus a macrolide may improve the outcome for elderly patients with community-acquired pneumonia (CAP). The prognoses and mortality rates for elderly patients with CAP who receive ceftriaxone combined with a 3-day course of azithromycin or a 10-day course of clarithromycin were compared in an open-label, prospective study. Of 896 assessable patients, 220 received clarithromycin and 383 received azithromycin. There were no significant differences between groups with regard to the severity score defined by the Pneumonia Patient Outcomes Research Team (PORT) study group; the incidence of bacteremia was also not significantly different. However, for patients treated with azithromycin, the length of hospital stay was shorter (mean+/-SD, 7.4+/-5 vs. 9.4+/-7 days; P<.01) and the mortality rate was lower (3.6% vs. 7.2%; P<.05), compared with those treated with clarithromycin. There might be a difference in the outcome for patients with CAP depending on the macrolide used. A shorter treatment course with azithromycin may result in better compliance with therapy.

Determination of intracellular efficacies of azithromycin against Leishmania major infection in human neutrophils in vitro

Azithromycin is one of a new class of antibiotics known as azalides. Azithromycin has high tissue affinity and this feature is thought to be due to the presence of two basic tertiary amine groups. Leishmania major, one of the causative agents of cutaneous leishmaniosis, is an obligate intracellular parasite. In this in vitro study, the potential anti-leishmanial effect of azithromycin upon intracellular forms namely the amastigote of L. major in mice peritoneal macrophages was investigated. L. major promastigotes were propagated in RPMI-1640 supplemented with 20% fetal calf serum in the log phase. The percentage of phagocytosis and microbiacidal activity of azithromycin on macrophages was assessed in the control and study groups by fluorescence microscopy, using acridine orange. Our results showed that at all the concentrations used (0.05, 0.1, 0.3, 0.6 microg ml(-1)) azithromycin had no inhibitory effect on the phagocytic capacity of mouse peritoneal macrophages. Although no significant difference was observed for leishmaniacidal activity between the study and the control groups at a concentration of 0.05 microg ml(-1) (p>0.05), a significant (p<0.05) increase in leishmaniacidal activity was detected at 0.1, 0.3 and 0.6 microg ml(-1). As a result, azithromycin does not provide any contribution to the phagocytosis of L. major promastigotes in macrophages in vitro, but it increases the intracellular killing rates of amastigotes. These results suggest that it has a potential anti-leishmanial effect, and may provide a significant advantage in the treatment of the disease.

Mycoplasma pneumoniae and Chlamydia pneumoniae in asthma: effect of clarithromycin

STUDY OBJECTIVES

To determine the effect of clarithromycin therapy in patients with asthma.

DESIGN

Randomized, double blind, placebo-controlled trial.

SETTING

A tertiary referral center.

PATIENTS OR PARTICIPANTS

Fifty-five subjects with chronic, stable asthma recruited from the general Denver, CO, community.

INTERVENTIONS

Patients underwent airway evaluation for Mycoplasma pneumoniae and Chlamydia pneumoniae by polymerase chain reaction (PCR) and culture, followed by treatment with clarithromycin, 500 bid, or placebo for 6 weeks.

MEASUREMENTS AND RESULTS

Outcome variables were lung function, sinusitis as measured by CT, and the inflammatory mediators tumor necrosis factor (TNF)-alpha, interleukin (IL)-2, IL-4, IL-5, and IL-12 messenger RNA (mRNA) measured via in situ hybridization, in airway biopsies, and BAL. Mycoplasma or chlamydia were detected by PCR in 31 of 55 asthmatics. Treatment resulted in a significant improvement in the FEV(1), but only in the PCR-positive subjects (2.50 +/- 0.16 to 2.69 +/- 0.19 L, mean +/- SEM; p = 0.05). This was not appreciated in the PCR-negative subjects (2.59 +/- 0.24 to 2.54 +/- 0.18 L, p = 0.85) or the PCR-positive or PCR-negative subjects who received placebo. Sinus CTs revealed no change in sinusitis with clarithromycin treatment. In situ hybridization revealed no significant difference in baseline airway tissue or BAL-mediator expression between the PCR-positive and PCR-negative subjects. However, the PCR-positive subjects who received clarithromycin demonstrated a reduction in TNF-alpha (p = 0.006), IL-5 (p = 0.007), and IL-12 (p = 0.004) mRNA in BAL and TNF-alpha mRNA in airway tissue (p = 0.0009). The PCR-negative subjects who received clarithromycin only demonstrated a reduction in TNF-alpha (p = 0.01) and IL-12 (p = 0.002) mRNA in BAL and TNF-alpha mRNA in airway tissue (p = 0.004). There were no significant differences in cytokine expression in those subjects who received placebo.

CONCLUSIONS

These observations support the hypothesis that clarithromycin therapy improves lung function, but only in those subjects with positive PCR findings for M pneumoniae or C pneumoniae.

Pharmacologic management of common lower respiratory tract disorders in women

In a primary care setting, midwives collaboratively manage common lower respiratory conditions that require pharmacologic therapy. Current knowledge about the indications, use, adverse effects, and potential side effects of these medications is essential. This article reviews the drugs most frequently used for the outpatient treatment of asthma, tuberculosis, pneumonia, and bronchitis (acute and chronic) in adults. Recommendations from the Centers for Disease Control and Prevention guidelines and professional societies are presented. Drug pharmacology and adverse effects are discussed in detail.

Systemic antibiotic agents

Understanding the breadth of systemic antimicrobial agents available for use by the dermatologist and their associated side-effect profiles and drug interactions allows the clinician to offer patients optimal care in the management of cutaneous infectious disease.

Lepromatous leprosy in an HIV-positive patient in Spain

We report a 35-year-old HIV-positive male affected by lepromatous leprosy which, to our knowledge, is the first case of its kind in Spain. The relationship between the two conditions is discussed.

The macrolides: erythromycin, clarithromycin, and azithromycin

In addition to erythromycin, macrolides now available in the United States include azithromycin and clarithromycin. These two new macrolides are more chemically stable and better tolerated than erythromycin, and they have a broader antimicrobial spectrum than erythromycin against Mycobacterium avium complex (MAC), Haemophilus influenzae, nontuberculous mycobacteria, and Chlamydia trachomatis. All three macrolides have excellent activity against the atypical respiratory pathogens (C. pneumoniae and Mycoplasma species) and the Legionella species. Azithromycin and clarithromycin have pharmacokinetics that allow shorter dosing schedules because of prolonged tissue levels. Both azithromycin and clarithromycin are active agents for MAC prophylaxis in patients with late-stage acquired immunodeficiency syndrome (AIDS), although azithromycin may be the preferable agent because of fewer drug-drug interactions. Clarithromycin is the most active MAC antimicrobial agent and should be part of any drug regimen for treating active MAC disease in patients with or without AIDS. Although both azithromycin and clarithromycin are well tolerated by children, azithromycin has the advantage of shorter treatment regimens and improved tolerance, potentially improving compliance in the treatment of respiratory tract and skin or soft tissue infections. Intravenously administered azithromycin has been approved for treatment of adults with mild to moderate community-acquired pneumonia or pelvic inflammatory diseases. An area of concern is the increasing macrolide resistance that is being reported with some of the common pathogens, particularly Streptococcus pneumoniae, group A streptococci, and H. influenzae. The emergence of macrolide resistance with these common pathogens may limit the clinical usefulness of this class of antimicrobial agents in the future.

The role of newer macrolides in the treatment of community-acquired respiratory tract infection. A review of experimental and clinical data

The macrolide class of antibiotics is well established and often recommended for use in the treatment of community-acquired respiratory tract infection (RTI). The newer agents clarithromycin and azithromycin are frequently prescribed as first- or second-line therapy, and have been considered as superior to erythromycin in microbiological activity and clinical efficacy. In-vitro data show that clarithromycin and azithromycin have good activity (MIC < or = 0.5 microg/ml) against certain RTI pathogens. However the activity of both compounds is intrinsically low against Haemophilus influenzae whilst several other important RTI pathogens - notably Streptococcus pneumoniae and Streptococcus pyogenes - exhibit a high prevalence of resistance to them. In many countries, the prevalence of resistance to clarithromycin and azithromycin is still rising with cross resistance with erythromycin. Maximum serum concentrations of clarithromycin and azithromycin are lower than the MIC90s for these agents against H. influenzae and S. pneumoniae. Concentrations in tissues have been reported to be much higher than those in serum. However, the high concentrations observed in tissues are largely a reflection of high concentrations inside cells. Concentrations of clarithromycin and azithromycin in extracellular tissue fluids, where Haemophilus and streptococci are located, are in equilibrium with concentrations in the serum, and remain low. It has been suggested that phagocytes deliver azithromycin to infection sites in a targeted fashion, but the evidence in support of this hypothesis is weak. Recent clinical experience with clarithromycin and azithromycin is consistent with preclinical results, and suggests that these agents have limited efficacy against certain respiratory infections. Clarithromycin and azithromycin are the first choice treatment of atypical infections caused by intracellular pathogens. For community-acquired RTIs, where H. influenzae and S. pneumoniae are present, they may no longer be an appropriate choice for first-line therapy. Indeed, in areas where levels of drug resistant S. pneumoniae are high, their use may be questionable as second-line therapy.

Antimicrobial agents for the dermatologist. II. Macrolides, fluoroquinolones, rifamycins, tetracyclines, trimethoprim-sulfamethoxazole, and clindamycin

This article is the second of a two-part series reviewing antimicrobial agents that are used by the dermatologist. In part I we reviewed beta-lactam antibiotics and related compounds. In this section we again emphasize some newer agents (macrolides, fluoroquinolones) as well as some of the more commonly employed older agents (rifamycins, tetracyclines, trimethoprim-sulfamethoxazole, and clindamycin.