Antibiotic Recommendations

Published on 10/02/2015 by admin

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Last modified 10/02/2015

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185 Antibiotic Recommendations

Ellen M. Slaven

The proper selection of antibiotic therapy in the setting of the emergency department (ED) is often complicated. The offending pathogen is rarely known with certainty, and emergency physicians must contend with diseases caused by emerging microbes, such as human immunodeficiency virus and the coronavirus that causes sudden acute respiratory syndrome. Many common bacterial pathogens have developed novel antimicrobial resistance patterns, such as drug-resistant Streptococcus pneumoniae and Escherichia coli, and some well-known bacteria have developed new strains, such as community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA). Complicating this challenge is a perpetually growing list of new antimicrobial agents, and emergency physicians clearly must remain diligent to keep current with the ever-changing arena of infectious diseases that are frequently encountered in the ED.

Fortunately, many helpful resources are available, such as local hospital antibiograms and hospital-specific protocols. National guidelines such as the Surviving Sepsis Campaign and the Centers for Disease Control and Prevention (CDC) guidelines for sexually transmitted diseases provide helpful references. The annually updated Sanford Guide to Antimicrobial Therapy remains an invaluable up-to-date tool literally found within one’s pocket.

In general, antibiotic therapy is empiric, based on epidemiologic data of the most likely encountered pathogen. Critically ill patients benefit from early and appropriate antibiotic therapy and therefore initially require broad-spectrum therapy, unless a specific pathogen has been identified. Whenever possible, the safest, least expensive, and easiest to administer antibiotic should be prescribed. Oral therapy is preferable over parenteral, and single-dose regimens eliminate concerns regarding compliance when compared with multidose regimens.

Recommendations for antibiotic therapy in the ED for selected infectious diseases are outlined in the sections that follow.

Odontogenic Infections

Penicillin (Pen Vee K, 500 mg orally [PO] four times daily for 5 to 7 days) is indicated for dentoalveolar abscesses, such as periapical abscesses. Clindamycin (300 mg PO four times daily for 5 to 7 days) is an alternative for penicillin-allergic patients. Significant abscesses (i.e., those causing facial swelling) require emergency drainage in addition to antibiotics. For patients admitted to the hospital with severe infection, ampicillin-sulbactam (1.5 g intravenously [IV] every 6 hours) is preferred. Clindamycin (900 mg IV every 6 hours) is again a suitable alternative.

Pharyngitis

Penicillin (Pen Vee K, 500 mg PO four times daily for 10 days) remains the drug of choice for group A streptococcal pharyngitis. A single intramuscular injection of benzathine penicillin (600,000 units if the patient’s weight is < 27 kg and 1.2 million units if it is >27 kg) may be administered to enhance compliance.

Patients with allergy to penicillin may be treated with azithromycin (500 mg PO on day 1, then 250 mg PO every day for 4 days). Group A Streptococcus has not developed resistance to penicillin, but approximately one third of isolates are resistant to macrolides or clindamycin. Linezolid (400 mg PO twice daily for 10 days) may be used for resistant strains.

Acute Sinusitis

Mild symptoms of acute sinusitis may initially be treated with decongestants and analgesics. Reserve antibiotics for those in whom such conservative therapy fails and in patients with more severe symptoms, such as severe maxillary or facial pain and fever. High-dose amoxicillin is the preferred agent (adults: 1 g PO three times daily for 10 days; children: 90 mg/kg/day PO divided three times daily for 10 days).

Otitis Externa

Hydrocortisone, polymyxin B, and neomycin combined (Cortisporin otic, 4 drops in affected ear four times daily for 7 days) remain the standard therapy for otitis externa. If the tympanic membrane is perforated, a preferred combination of ciprofloxacin with hydrocortisone (3 drops in affected ear twice daily for 7 days) is indicated because of the ototoxicity of neomycin. Removal of debris from the ear canal promotes enhanced entry of the medication deep into the canal. When the canal is sufficiently swollen, a wick may need to be carefully placed to allow medication penetration.

Otitis Media

A prudent approach is to withhold antibiotics for 48 hours in afebrile children with otitis media who are more than 2 years old and are without pain. Treat with high-dose amoxicillin for 7 days (adults: 1 g PO three times daily; children: 90 mg/kg/day PO divided three times daily). Alternative therapy is with azithromycin (adults: 500 mg PO on day 1, then 250 mg PO every day for 4 days; children: 10 mg/kg [maximum, 500 mg] PO on day 1, then 5 mg/kg [maximum, 250 mg] PO every day for 4 days).

Acute Bacterial Meningitis

The treatment of acute bacterial meningitis is guided by epidemiologic risk factors; likely pathogens are determined primarily by the age of the patient and by exposure following trauma or surgical intervention. The goal of treatment is to administer antibiotics within 30 minutes of the patient’s arrival to the ED.

A Cochrane Review of more than 4000 patients with acute bacterial meningitis concluded that the use of adjunctive steroids decreases neurologic sequelae including hearing loss. Dexamethasone should be given intravenously 15 minutes before or concomitantly with the first dose of antibiotics and continued for 4 days (adults: 10 mg every 6 hours; children: 0.15 mg/kg every 6 hours).

Neonates (<1 month old): Combination treatment with ampicillin (200 mg/kg/day IV divided every 6 hours) and cefotaxime (300 mg/kg/day IV divided every 6 hours) targets the most common pathogens, which are group B Streptococcus, E. coli, and Listeria species.

Age 1 month to 50 years: Ceftriaxone (adults: 2 g IV every 12 hours; children: 100 mg/kg/day [maximum, 2 g] IV divided every 12 hours) with vancomycin (adults: 15-20 mg/kg [maximum, 2 g] IV every 12 hours; children: 15 mg/kg [maximum, 2 g] IV every 6 hours) provides coverage against S. pneumoniae (including penicillin-resistant strains), Neisseria meningitidis, and Haemophilus influenzae (although now rare because of the Hib vaccine).

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