Acne is common among adolescents and adults. Guidelines for treatment of acne were last published by the American Academy of Dermatology in 2016.

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.

Acne is common among adolescents and young adults, but its prevalence appears to have increased in people of all ages due to prolonged wearing of masks during the COVID-19 pandemic. Guidelines for treatment of acne were last published in 2016.

The FDA has approved omadacycline (Nuzyra – Paratek), a semisynthetic tetracycline derivative, for once-daily IV and oral treatment of community-acquired bacterial pneumonia (CAP) and acute bacterial skin and skin structure infections (ABSSSIs) in adults.

A reader has questioned why the label for the COX-2 selective NSAID celecoxib (Celebrex, and generics), which contains a sulfonamide moiety, states that it is contraindicated for use in patients with an allergy to sulfonamides, while the labels of some other sulfonamide drugs recommend either caution or no precautions at all. The concept of cross-reactivity among sulfonamide drugs, particularly between antibacterial and nonantibacterial sulfonamides, has been controversial for many years.

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

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.

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.

Antimicrobial prophylaxis can decrease the incidence of postoperative surgical site infection after some procedures. Since the last Medical Letter article on this subject, consensus guidelines have been published. Recommendations for prophylaxis in specific surgical procedures are listed in Table 1.

The FDA has approved patiromer (Veltassa – Relypsa), an oral potassium binder, for treatment of hyperkalemia. It is the first drug to be approved for this indication since the cation-exchange resin sodium polystyrene sulfonate (Kayexalate, and others) in 1958. Patiromer is not indicated for emergency correction of life-threatening hyperkalemia. Sodium zirconium cyclosilicate, another oral potassium binder, is currently being reviewed by the FDA; a decision on its approval is expected in May 2016.

The pathogenesis of acne is multifactorial: follicular hyperkeratinization, bacteria, sebum production, androgens, and inflammation all play a role. The gram-positive microaerophilic bacteria Propionibacterium acnes promotes development of acne lesions by secreting chemotactic factors that attract leukocytes to the follicle, causing inflammation.

The FDA has approved oritavancin (Orbactiv – The Medicines Company), a long-acting lipoglycopeptide antibiotic given as a single intravenous (IV) dose, for treatment of acute bacterial skin and skin structure infections caused by susceptible gram-positive bacteria in adults. It is the third lipoglycopeptide antibiotic to be marketed in the US; telavancin (Vibativ) and dalbavancin (Dalvance) were approved earlier.

The FDA has approved two new drugs for treatment of adults with acute bacterial skin and skin structure infections caused by susceptible gram-positive bacteria. Dalbavancin (Dalvance – Durata) is a long-acting intravenous (IV) lipoglycopeptide antibiotic similar to telavancin (Vibativ). Tedizolid phosphate (Sivextro – Cubist) is an IV and oral oxazolidinone antibacterial drug similar to linezolid (Zyvox). A third IV antibiotic, oritavancin (Orbactiv), recently approved by the FDA for the same indication, will be reviewed in a future issue.

Aminosalicylates are effective for induction and maintenance of remission in mild to moderate ulcerative colitis. They are not recommended for treatment of Crohn's disease.

FORMULATIONS — Oral mesalamine is rapidly absorbed in the small intestine and most of the drug does not reach the colon. Pentasa releases mesalamine gradually throughout the gastrointestinal tract. Delzicol, Asacol HD, Lialda, and Apriso delay the release of the drug until it reaches the distal ileum and colon. Sulfasalazine (Azulfidine, and generics), balsalazide (Colazal, and others), and olsalazine (Dipentum) are prodrugs; mesalamine is azo-bonded to a second moiety and released in the colon following bacterial cleavage of the bond. Mesalamine is also available as an enema (Rowasa, and generics) and as a rectal suppository (Canasa).

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 text that follows reviews some common bacterial infections and their empiric treatment pending the results of culture and susceptibility testing. The recommendations made here are based on the results of susceptibility studies, clinical trials, and the opinions of Medical Letter reviewers. Tables 1 and 2 list the usual dosages of antibacterial drugs.

The pathogenesis of acne is multifactorial: follicular hyperkeratinization, bacteria, sebum production, androgens, and inflammation all play a role. The gram-positive microaerophilic bacteria Propionibacterium acnes promote development of acne lesions by secreting chemotactic factors that attract leukocytes to the follicle, causing inflammation.

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.

A reader suggested that our July 23 article on Drugs for Urinary Tract Infection (Med Lett Drugs Ther 2012; 54:57)¹ should have included information on the cost of the drugs we recommended for treatment of acute uncomplicated cystitis.

Trimethoprim/sulfamethoxazole DS — Generic formulations are available at large discount pharmacies for $4 for 20 tablets. Trimethoprim/sulfamethoxazole DS is generally found on tier 1 (lowest co-pay) of insurance company formularies.

Nitrofurantoin monohydrate/macrocrystals — The wholesale acquisition cost of the generic formulation is about $2.50 per tablet (PricePointRx™).² The drug is on tier 1 of some insurance company formularies, but on tier 2 or 3 of others.

Fosfomycin — Available only as Monurol, a single dose of fosfomycin is effective in most cases of acute uncomplicated cystitis, but the manufacturer charges a wholesale acquisition cost of more than $40 for that dose (PricePointRx™).² Most insurance companies place Monurol on tier 3 of their formularies, or do not include it on their formularies at all.

Not recommended: Ciprofloxacin – Fluoroquinolones should not be used empirically to treat acute uncomplicated cystitis. The fact that ciprofloxacin is available at large discount pharmacies for $4 for 20 500-mg tablets and is on tier 1 on most insurance company formularies may be part of the reason for its continued overuse.

1. Drugs for urinary tract infection. Med Lett Drugs Ther 2012; 54:57.

2. PricePointRx™. Reprinted with permission by FDB. All rights reserved. ©2012. http://www.firstdatabank.com/support/drug-pricing-policy.aspx. Accessed July 31, 2012. Actual retail prices may be higher.

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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.