The FDA has approved Exblifep (Allecra), a fixed-dose combination of the cephalosporin cefepime and the beta-lactamase inhibitor enmetazobactam, for IV treatment of adults with complicated urinary tract infections (cUTIs), including pyelonephritis, caused by designated susceptible microorganisms (see Spectrum of Activity). Exblifep is the first product that contains enmetazobactam to be approved in the US.

Most respiratory tract infections are caused by viruses. Bacterial respiratory tract infections are usually treated empirically with antibiotic therapy that targets the most probable causative pathogens. Recommended antibiotic regimens for outpatient treatment of some common respiratory tract infections are listed in Table 1 for adults and Table 2 for children.

This article includes recommendations for management of most sexually transmitted infections (STIs) other than HIV and viral hepatitis. Some of the indications and dosages recommended here have not been approved by the FDA (see Table 1).

Clostridioides (formerly Clostridium) difficile infection (CDI) is the most common infectious cause of healthcare-associated diarrhea in adults. Guidelines on management of CDI have recently been updated.

Treatment of community-acquired pneumonia (CAP) is usually empiric, with selected antibiotic regimens directed against some of the most common causative pathogens. Recommended empiric regimens are listed in Table 2; recommended antibiotic dosages for treatment of CAP are listed in Tables 3 and 4. Joint guidelines for treatment of CAP by the American Thoracic Society and the Infectious Diseases Society of America (ATS/IDSA) were updated in 2019.

The FDA has approved cefiderocol (Fetroja – Shionogi), a new IV cephalosporin antibiotic, for treatment of complicated urinary tract infections (UTI) caused by susceptible gram-negative bacteria in adults who have limited or no alternative treatment options.

This issue includes reviews of drugs for glaucoma, age-related macular degeneration (AMD), bacterial conjunctivitis, and dry eye disease. Allergic conjunctivitis is reviewed in a separate issue.

Patients who receive pretravel advice can reduce their risk for many travel-related conditions. Vaccines recommended for travelers are reviewed in a separate issue.

Lefamulin (Xenleta – Nabriva), a semisynthetic pleuromutilin antibiotic, has been approved by the FDA for IV and oral treatment of community-acquired bacterial pneumonia (CABP) in adults. It is the first systemic pleuromutilin antibiotic to be approved in the US; retapamulin (Altabax), a 1% topical ointment for treatment of impetigo, was approved in 2007.

The FDA has approved rifamycin (Aemcolo – Cosmo/ Aries), a minimally absorbed oral antibiotic, for treatment of adults with travelers' diarrhea (TD) caused by noninvasive strains of Escherichia coli. It is not recommended for treatment of diarrhea that is complicated by fever and/or bloody stools. Topical and injectable formulations of rifamycin have been used in Europe for other indications for many years.

The FDA has approved the new aminoglycoside antibiotic plazomicin (Zemdri – Achaogen) for IV treatment of adults with complicated urinary tract infections (cUTIs). Plazomicin is active against multi-drug- resistant Enterobacteriaceae, including strains resistant to other aminoglycosides.

The FDA has approved a 6% otic suspension formulation of the fluoroquinolone antibiotic ciprofloxacin (Otiprio – Otonomy) for single-dose treatment of acute otitis externa (swimmer's ear) caused by Pseudomonas aeruginosa or Staphylococcus aureus in patients ≥6 months old. Otiprio was approved earlier for prophylaxis in children with bilateral otitis media with effusion who are undergoing tympanostomy tube placement.

The FDA has required changes in the labeling of all systemic fluoroquinolone antibiotics to strengthen warnings about the risk of severe hypoglycemia and mental health effects associated with their use.1

An FDA review identified 67 cases of hypoglycemic coma associated with fluoroquinolone use, 22 of which resulted in death or disability. Most cases occurred in patients with risk factors such as diabetes (especially those taking a sulfonylurea), older age, or renal insufficiency.1 In observational studies in older adults and patients with diabetes, fluoroquinolones have been associated with increased risks of hypo- and hyperglycemia.2,3 Patients taking a fluoroquinolone (especially those with risk factors) should be counseled about the symptoms of hypoglycemia and monitored for blood glucose disturbances. The drug should be stopped if dysglycemia occurs.

The labels of all systemic fluoroquinolones will now include warnings about delirium, agitation, nervousness, and disturbances in attention, memory, and orientation. These effects can occur after a single fluoroquinolone dose; the drug should be stopped if such effects occur. Systemic fluoroquinolones can also cause persistent or permanent peripheral neuropathy,4 and their use has been associated with an increased risk of pseudotumor cerebri syndrome.5

Other serious adverse effects associated with use of systemic fluoroquinolones include tendinitis and tendon rupture, exacerbation of myasthenia gravis, Clostridium difficile infection, and (except for delafloxacin [Baxdela]) QT-interval prolongation and torsades de pointes. The FDA recommends avoiding use of fluoroquinolones in patients with uncomplicated urinary tract infection, acute sinusitis, or acute exacerbation of chronic bronchitis, except when no alternative treatment option is available.6

Additional Content Available Online: Comparison Table: Some Systemic Fluoroquinolones

1. FDA. July 10, 2018. Available at: www.fda.gov. Accessed August 2, 2018.
2. LY Park-Wyllie et al. Outpatient gatifloxacin therapy and dysglycemia in older adults. N Engl J Med 2006; 354:1352.
3. HW Chou et al. Risk of severe dysglycemia among diabetic patients receiving levofloxacin, ciprofloxacin, or moxifloxacin in Taiwan. Clin Infect Dis 2013; 57:971.
4. In brief: Fluoroquinolones and peripheral neuropathy. Med Lett Drugs Ther 2013; 55:89.
5. M Sodhi et al. Oral fluoroquinolones and risk of secondary pseudotumor cerebri syndrome: nested case-control study. Neurology 2017; 89:792.
6. Alternatives to fluoroquinolones. Med Lett Drugs Ther 2016; 58:75.

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The FDA has approved a fixed-dose combination of meropenem, a carbapenem antibiotic, and vaborbactam, a new beta-lactamase inhibitor (Vabomere – Melinta), for IV treatment of adults with complicated urinary tract infections (UTIs) that are proven or strongly suspected to be caused by Escherichia coli, Klebsiella pneumoniae, or Enterobacter cloacae spp. complex. Meropenem (Merrem, and generics) has been approved for years for treatment of complicated skin and skin structure infections, intra-abdominal infections, and bacterial meningitis. Resistance to meropenem and other carbapenems, mainly due to production of carbapenemases and other extended-spectrum beta-lactamases (ESBLs), has been increasing worldwide, particularly among Enterobacteriaceae. Vabomere is the first carbapenem/beta-lactamase inhibitor combination to be marketed in the US.

The FDA has approved delafloxacin (Baxdela – Melinta), an anionic fluoroquinolone antibiotic, for oral and parenteral treatment of adults with acute bacterial skin and skin structure infections (ABSSSIs), including those caused by methicillin-resistant Staphylococcus aureus (MRSA). It is the first fluoroquinolone to be approved for treatment of MRSA.

View the Comparison Table: Some Antibiotics for MRSA Skin and Skin Structure Infections

View the Comparison Table: Some Systemic Fluoroquinolones (online only)

Bacterial infections in adults are generally treated empirically, with the antibiotic covering most, but not all, of the potential causative pathogens. For some infections, culture and sensitivity testing can guide treatment, allowing for use of narrower-spectrum antibiotics. The recommended dosages and durations of antibiotic treatment for common respiratory, skin, and urinary tract infections are listed in Tables 1-3. Infectious disease experts now recommend shorter treatment durations for many infections to reduce the development of antimicrobial resistance and minimize adverse effects.

About 50% of the world’s population is infected with Helicobacter pylori. These gastric bacteria can cause chronic inflammation and have been associated with development of gastritis, peptic ulcer disease, gastric adenocarcinoma, and gastric mucosa-associated lymphoid tissue (MALT) lymphoma. Eradication of H. pylori can promote gastric healing, prevent recurrence of duodenal and gastric ulcers, and reduce the incidence of gastric cancer. Guidelines for treatment of H. pylori infection were updated recently.

The text and tables that follow include recommendations for management of sexually transmitted infections (STIs) other than HIV and viral hepatitis. Some of the indications and dosages recommended here have not been approved by the FDA.

The FDA has approved Otovel (Arbor), a combination of the fluoroquinolone antibiotic ciprofloxacin 0.3% and the corticosteroid fluocinolone acetonide 0.025%, for otic treatment of acute otitis media with tympanostomy tubes (AOMT) in children ≥6 months old. It is the second fluoroquinolone/corticosteroid combination to be approved for this indication; ciprofloxacin 0.3%/dexamethasone 0.1% (Ciprodex) has been available for many years. In December 2015, a suspension of ciprofloxacin 6% (Otiprio) was approved for otic treatment of bilateral otitis media with effusion in children undergoing tympanostomy tube placement.

The FDA has announced that it is requiring changes in the labeling of systemic fluoroquinolones to warn that the risk of serious adverse effects, including tendinitis, peripheral neuropathy and CNS effects, generally outweighs their benefit for the treatment of acute sinusitis, acute exacerbations of chronic bronchitis, and uncomplicated urinary tract infections. For these infections, the new labels will recommend reserving fluoroquinolones for patients with no other treatment options.

The FDA has approved ceftazidime/avibactam (Avycaz – Actavis) for IV treatment of complicated urinary tract and intra-abdominal infections in adults who have limited or no other treatment options. Ceftolozane/tazobactam (Zerbaxa – Cubist), another cephalosporin/beta-lactamase inhibitor combination, was approved in 2014.

The FDA has approved ceftolozane/tazobactam (Zerbaxa – Cubist), a combination of a new cephalosporin antibiotic and a beta-lactamase inhibitor, for intravenous treatment of complicated urinary tract and intra-abdominal infections in adults.

The treatment of atrial fibrillation includes anticoagulation, rate control, and rhythm control. New US guidelines for the management of atrial fibrillation have recently been published.

Methicillin-resistant Staphylococcus aureus (MRSA), which was traditionally a nosocomially-acquired organism but now frequently occurs in the absence of healthcare exposure, is the predominant cause of suppurative skin and soft-tissue infections in many parts of the US. Community-associated MRSA usually causes furunculosis, purulent cellulitis, and abscesses, but necrotizing fasciitis, necrotizing pneumonia, and sepsis can also occur.

The FDA is requiring new warnings about peripheral neuropathy in the labeling of all oral and injectable fluoroquinolones. The potential for this class of antibiotics to cause peripheral neuropathy was first identified more than 10 years ago and a warning was added to their labels in 2004. The new warnings are based on a recent review of the FDA’s Adverse Event Reporting System (AERS) database.1

The onset of peripheral neuropathy can occur rapidly, often within a few days of starting a fluoroquinolone, and in some patients the disorder may be permanent. Symptoms include pain, tingling, burning, numbness, weakness, and change in sensation to touch, pain, and temperature in the arms and/or legs. If peripheral neuropathy develops in a patient taking a fluoroquinolone, the drug should be stopped and an antibacterial from a different class should be used instead.2

1. FDA Drug Safety Communication: FDA requires label changes to warn of risk for possibly permanent nerve damage from antibacterial fluoroquinolone drugs taken by mouth or by injection. Available at http://www.fda.gov. Accessed November 1, 2013.

2. Drugs for bacterial infections. Treat Guidel Med Lett 2013; 11:65.

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Bedaquiline (bed ak' wi leen; Sirturo – Janssen), a diarylquinoline antimycobacterial, has been given accelerated approval by the FDA as an orphan drug for use in addition to other drugs for treatment of adults with multidrug-resistant pulmonary tuberculosis (MDR-TB). It is the first drug approved specifically to treat MDR-TB.

The FDA has announced that it is requiring changes in the labeling of the macrolide antibiotic azithromycin (Zithromax, Zmax) to warn about the risk of QT prolongation and cardiac arrhythmias.1 The new warnings are based on a retrospective study in The New England Journal of Medicine (reviewed previously in The Medical Letter2), which found that among patients who received 347,795 prescriptions for azithromycin, there were 29 cardiovascular deaths, a significantly higher rate than the 42 that occurred among patients who received 1,348,672 prescriptions for amoxicillin (which does not prolong the QT interval) or the 41 that occurred among 1,391,180 patients who took no antibiotics. The risk with azithromycin was much higher in patients with cardiovascular risk factors.3

Other macrolides and fluoroquinolones can also prolong the QT interval. In the retrospective study, the risk of cardiovascular death with levofloxacin was not significantly different from the risk with azithromycin. As with any retrospective study, the possibility that baseline differences between patients taking azithromycin and those taking other or no antimicrobials could have been responsible for the difference in cardiovascular outcomes cannot be entirely ruled out.

1. FDA Drug Safety Communication: Azithromycin (Zithromax or Zmax) and the risk of potentially fatal heart rhythms. Available at www.fda.gov/drugs/drugsafety/ucm341822.htm. Accessed March 14, 2013.

2. In brief: safety of azithromycin. Med Lett Drugs Ther 2012; 54:45.

3. WA Ray et al. Azithromycin and the risk of cardiovascular death. N Engl J Med 2012; 366:1881.

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Drugs for glaucoma, age-related macular degeneration, bacterial conjunctivitis, and dry eyes are reviewed here. Drugs for the treatment of allergic conjunctivitis will be reviewed in a future issue of Treatment Guidelines on Drugs for Allergic Disorders.

Antimicrobial prophylaxis can decrease the incidence of postoperative infection, particularly surgical site infection, after some procedures. Recommendations for such prophylaxis are listed in the table that begins on page 74. Antimicrobial prophylaxis for dental procedures to prevent endocarditis was recently discussed in The Medical Letter.

The most recent guidelines from the Infectious Diseases Society of America (IDSA) and its European counterpart on the choice of antimicrobials for treatment of uncomplicated urinary tract infections (UTIs) in non-pregnant women focus on the unnecessary use of fluoroquinolones to treat uropathogens that are increasingly becoming resistant to them. Resistance of Escherichia coli to ciprofloxacin in the US has increased from 3% in 2000 to 17.1% in 2010.

Patients planning to travel to other countries often ask for information about appropriate vaccines and prevention of diarrhea and malaria. More detailed advice for travelers is available from the Centers for Disease Control and Prevention (CDC) at www.cdc.gov/travel. Guidelines are also available from the Infectious Diseases Society of America (IDSA).

Tuberculosis (TB) is still a common cause of death worldwide, and the prevalence of drug-resistant TB poses challenges to its treatment and control. Guidelines with detailed management recommendations are available from the American Thoracic Society, Centers for Disease Control and Prevention (CDC) and Infectious Diseases Society of America (IDSA).

The FDA has approved fidaxomicin (Dificid – Optimer), a new oral macrolide antibiotic, for treatment of Clostridium difficile-associated diarrhea in patients ≥18 years old. The incidence and severity of C. difficile infection (CDI) have increased in recent years with the emergence of an epidemic hypervirulent strain (NAP1/B1/027), possibly related to widespread use of fluoroquinolones.

Peptic ulcer disease (PUD) is usually caused by nonsteroidal anti-inflammatory drugs (NSAIDs) or by infection with Helicobacter pylori. Gastroesophageal reflux disease (GERD) can be caused by transient lower esophageal sphincter relaxation, reduced lower esophageal sphincter tone, hiatal hernia, delayed gastric emptying or hormonal changes due to pregnancy. Acid suppressive therapy is the cornerstone of management for both PUD and GERD.

A Medical Letter reader has asked us to review the safety of the fluoroquinolone antibiotic levofloxacin (Levaquin – Ortho-McNeil-Janssen), which has just been approved for generic use by the FDA and has been at the center of some recent lawsuits regarding the adequacy of its safety warnings.

Clostridium difficile infection (CDI) is the most common infectious cause of healthcare-associated diarrhea in adults. The incidence and severity of CDI have increased in recent years with the emergence of an epidemic virulent strain (NAP1/BI/027). Common risk factors include admission to a healthcare facility, increasing age and severity of underlying illness, gastric acid suppression and exposure to antimicrobials, particularly clindamycin, ampicillin, cephalosporins or fluoroquinolones. Patients who develop CDI while receiving a precipitating antibiotic should have the antibiotic discontinued, if possible, or switched to another appropriate antimicrobial with a lower risk of CDI.

Many infections can be transmitted during sexual contact. The text and tables that follow are limited to management of sexually transmitted infections (STIs) other than HIV, viral hepatitis and enteric infections. The drugs of choice, their dosages and alternatives are listed in a table that begins on page 54. A table listing the adverse effects of some of these antimicrobials begins on page 58.

The text below reviews some common bacterial infections and their treatment. The recommendations made here are based on the results of susceptibility studies, clinical trials and the opinions of Medical Letter consultants.

Drugs for glaucoma, age-related macular degeneration, bacterial conjunctivitis, and dry eyes are reviewed here. Ophthalmic drugs can have local and systemic adverse effects. In addition, for some elderly patients, the complexity of self-administering numerous ophthalmic drugs may be the limiting factor in their ability to care for themselves. Drugs for the treatment of allergic conjunctivitis will be reviewed in a future issue of Treatment Guidelines on Drugs for Allergic Disorders.

The FDA has approved the fluoroquinolone besifloxacin 0.6% ophthalmic suspension (Besivance - Bausch & Lomb) for treatment of bacterial conjunctivitis caused by susceptible bacteria. According to the manufacturer, this product was developed specifically for ophthalmic use in a specialized vehicle designed to prolong contact time on the ocular surface. Besifloxacin is not available for systemic use.

Peptic ulcers caused by treatment with nonsteroidal anti-inflammatory drugs (NSAIDs) are mainly gastric ulcers. Most duodenal and other gastric ulcers are caused by the gram-negative bacillus Helicobacter pylori. Gastroesophageal reflux disease (GERD) is caused by gastric acid reflux into the esophagus. Drugs that suppress gastric acid production are the primary treatment for GERD and peptic ulcers.

The FDA has approved azithromycin 1% ophthalmic solution (AzaSite - Inspire) for treatment of bacterial conjunctivitis in patients > 1 year old. It is formulated, according to the manufacturer, in a controlled-release delivery system that keeps the drug in the eye for several hours.

Many infections can be transmitted during sexual contact. The text and tables that follow are limited to management of sexually transmitted infections (STIs) other than HIV, viral hepatitis and enteric infections. Guidelines are available from the US Centers for Disease Control and Prevention (CDC) with detailed recommendations for treatment of these diseases.

Most patients with community-acquired pneumonia (CAP) are treated empirically. New guidelines published jointly by the Infectious Diseases Society of America and the American Thoracic Society have recently become available.

Information about empirical treatment of bacterial infections, emerging trends in antimicrobial resistance, new drugs and new data about older drugs continue to become available. Usual pathogens and empiric treatment for some common types of infections are summarized in the text and a table listing the drugs of choice and alternatives for each pathogen begins on page 40. The recommendations made here are based on the results of susceptibility studies, clinical trials and the opinions of Medical Letter consultants.

Drugs for glaucoma, age-related macular degeneration, bacterial and allergic conjunctivitis, and dry eyes are reviewed here. Ophthalmic drugs can have local and systemic adverse effects. In addition, for some elderly patients, the complexity of self-administering numerous ophthalmic drugs may be the limiting factor in their ability to care for themselves.

A study now available on the web site of The New England Journal of Medicine (LY Park-Wyllie et al. Outpatient gatifloxacin therapy and dysglycemia in older adults. www.nejm.org, published online March 1, 2006) reports an increased risk of hypoglycemia (RR 4.3) and hyperglycemia (RR 16.7) with use of gatifloxacin (Tequin), a fluoroquinolone antibiotic. The Medical Letter published an article on this risk in 2003 (vol. 45, page 64); at that time the extent to which other fluoroquinolones carried the same risk was unclear. The recent report indicates that, except for a slightly increased relative risk of hypoglycemia (RR 1.5) with levofloxacin (Levaquin), they do not. Gatifloxacin, levofloxacin, moxifloxacin (Avelox) and gemifloxacin (Factive) are more active than other quinolones against gram-positive organisms such as Streptococcus pneumoniae, including strains highly resistant to penicillin; they are sometimes called "the respiratory quinolones." Given the availability of other drugs with similar in vitro and clinical activity, there is no good reason to continue to use gatifloxacin.

Methicillin-resistant Staphylococcus aureus (MRSA) infections, which have been a concern for many years, previously occurred primarily in hospitalized patients and those recently treated with antibiotics. In the past few years, there has been an increasing incidence worldwide of community-associated (CA) MRSA infections in patients without recent antibiotic exposure or contact with the healthcare system.

Tuberculosis (TB) is still a problem in the United States, even though the incidence continues to decline in most of the country (MMWR Morbid Mortal Wkly Rep 2004; 53:209). Treatment of TB can be divided into treatment of latent infection diagnosed by a positive PPD and treatment of active clinical TB. Guidelines with detailed management recommendations are available from the US Centers for Disease Control and Prevention (CDC) (MMWR Morbid Mortal Wkly Rep 2003; 52RR-11:1).

Many infections can be transmitted during sexual contact. The text and tables that follow are limited to management of sexually transmitted infections (STIs) other than HIV, viral hepatitis and enteric infections. Guidelines are available from the US Centers for Disease Control and Prevention (CDC) with detailed recommendations for treatment of these diseases (MMWR Recomm Rep 2002; 51, RR-6:1). New guidelines are expected soon.

Gemifloxacin (Factive - Oscient), a new oral fluoroquinolone antibiotic, has been approved by the FDA for 5 days' treatment of acute bacterial exacerbations of chronic bronchitis (ABECB) and 7 days' treatment of mild to moderate community-acquired pneumonia (CAP) in adults. For the next 6-8 months it will only be available, presumably for commercial reasons, in states east of the Rocky Mountains.

Telithromycin (Ketek - Aventis) has been approved by the FDA for oral treatment of mild to moderate community-acquired pneumonia, acute exacerbations of chronic bronchitis and acute bacterial sinusitis in patients age 18 and older. The drug is the first in a new class of antibiotics, the ketolides, derived from the macrolide erythromycin. Telithromycin has been marketed in Europe since 2001.

Antimicrobial prophylaxis can decrease the incidence of infection, particularly surgical site infection, after certain operations, but this benefit must be weighed against the risks of toxic and allergic reactions, emergence of resistant bacteria, adverse drug interactions, superinfection and cost. Medical Letter consultants generally recommend antimicrobial prophylaxis only for procedures with high infection rates, those involving implantation of prosthetic material, and those in which the consequences of infection are likely to be especially serious.

Two new fluoroquinolone solutions, moxifloxacin 0.5% (Vigamox - Alcon) and gatifloxacin 0.3% (Zymar - Allergan) are now available in the US for ophthalmic use in treatment of bacterial conjunctivitis.

New drugs for bacterial infections and new information about older drugs continue to become available. Empirical treatment of some common bacterial infections is discussed in this article. A table listing the drugs of choice and alternatives for each pathogen begins on page 18. These recommendations are based on results of susceptibility studies, clinical trials and the opinions of Medical Letter consultants. Local resistance patterns should be taken into account. Trade names are listed on page 24.

Most peptic ulcers not caused by nonsteroidal anti-inflammatory drugs (NSAIDs) are associated with infection of the gastric mucosa by the gram-negative bacilli Helicobacter pylori. The majority of NSAID-related ulcers are gastric. H. pylori infection causes both duodenal and gastric ulcers. Eradication of H. pylori promotes healing and markedly decreases recurrence of both duodenal and gastric ulcers (A Shiotamni and DY Graham, Med Clin North Am 2002; 86:1447; FKL Chan and WK Leung, Lancet 2002; 360:933). The first step in the management of peptic ulcers is the diagnosis and treatment of H. pylori.

The choice of drugs for treatment of pneumonia depends on the most likely pathogens causing the infection and local antimicrobial resistance patterns. Factors such as severity of illness, presence of co-morbid conditions and whether the infection is community or hospital-acquired also need to be considered.

Superseded by Handbook of Antimicrobial Therapy
The Medical Letter article on Drugs and Vaccines against Biological Weapons, published in the previous issue (October 15, 2001, page 87), included a brief discussion of post-exposure prophylaxis of inhalation anthrax. Recent events call for more detail.

Older patients are especially susceptible to drug-induced cognitive impairment. They are more likely to be taking multiple drugs, to have higher blood levels of those drugs because of renal or hepatic dysfunction, and to have pre-existing cognitive problems that make it difficult to detect the role of drugs causing new symptoms or making old ones worse.

Gatifloxacin and moxifloxacin are now available for once-daily treatment of patients with community-acquired pneumonia, acute bacterial exacerbations of chronic bronchitis, or acute sinusitis.

Reports of adverse interactions between drugs continue to accumulate. Recently, the FDA has expanded the recommendations on drug interactions found in the package inserts of new drugs.

Sparfloxacin (Zagam - Rh ne-Poulenc Rorer) and levofloxacin (Levaquin - Ortho-McNeil) are the newest fluoroquinolone antimicrobials to be approved by the US Food and Drug Administration. Sparfloxacin in a once-daily oral preparation is being marketed for treatment of community-acquired pneumonia and acute bacterial exacerbations of chronic bronchitis. Levofloxacin, which is the active stereoisomer of ofloxacin (Floxin), is available for either oral or parenteral use; it is approved for oncedaily treatment of community-acquired pneumonia, acute exacerbations of chronic bronchitis, sinusitis, skin and skin structure infections and complicated urinary tract infections.

Enoxacin (en ox' a sin; Penetrex - Rh ne-Poulenc Rorer), a fluoroquinolone antimicrobial for oral use, has now been marketed in the USA for treatment of urinary tract infections and uncomplicated urethral or cervical gonorrhea.

Cefprozil (Cefzil - Bristol-Myers Squibb), a new oral second-generation cephalosporin, was recently released in the USA for treatment of pharyngitis, bronchitis, otitis media, and skin and skin-structure infections.

Temafloxacin (Omniflox - Abbott) and lomefloxacin (Maxaquin - Searle) are the latest fluoroquinolone antimicrobial agents to be approved by the US Food and Drug Administration (FDA) for oral treatment of various infections. Previously marketed include norfloxacin (Noroxin - Medical Letter, 29:25, 1987), ciprofloxacin (Cipro - Medical Letter, 30:11, 1988), and ofloxacin (Floxin - Medical Letter, 33:71, 1991). Norfloxacin is marketed only for treatment of urinary tract infections, and lomefloxacin only for treatment of urinary tract infections and bronchitis known to be caused by Haemophilus influenzae or Moraxella catarrhalis. Ciprofloxacin and ofloxacin are also available in parenteral formulations.

Ciprofloxacin hydrochloride (Cipro - Miles), a synthetic antibacterial agent, was recently marketed in the USA for oral treatment of a wide variety of infections. Ciprofloxacin is the second fluoroquinolone to become available in this country; norfloxacin (Noroxin - Medical Letter, 29:25, 1987) is marketed only for treatment of urinary tract infections. Fluoroquinolones are more potent and have a much broader spectrum of activity than older quinolones such as nalidixic acid (NegGram).