One and Done: Single-Dose Antimicrobials in the ED

We are all familiar with this label on the vials and packages of antimicrobials that have been prescribed to us over the course of the years:

How often is this to likely occur among patients discharged from the emergency department? The most challenging part of providing patients with prescriptions for antimicrobials to be filled once they are discharged from the emergency department is the fact that (a) there is no guarantee that the prescription will be filled; and (b) even if the prescription is filled, as soon at the patient starts to recover from their infection, he or she may discontinue the agent. This can lead to a return visit to the ED, especially if the patient’s condition fails to improve or worsens, and potentially increased costs to the healthcare system. Even if the patient is compliant with the treatment prescribed, antimicrobial resistance may increase, especially in cases where the outpatient treatment is suboptimal with poor penetration to the affected area and the course of therapy is unnecessarily prolonged.

So the question is: are there certain infectious conditions where we as clinicians can get away with administering a single dose of an antimicrobial agent to a patient in the emergency department and be safe to say that the patient has been effectively treated? In other words, is the concept of “one [dose of an antimicrobial agent] and done” adequate and effective?

The answer: yes, I believe there are. The advantages are quite obvious. There is direct observation of the patient actually receiving treatment; compliance with treatment is essentially not something that we need to be concerned about, and high concentrations of the antimicrobial agent may be reached to effectively cure the infection.

Before delving into specific infectious diseases, there are some criteria that should be fulfilled prior to making the decision that a patient’s condition allows for the administration of a single dose of an antimicrobial agent in the emergency department (adapted and modified from Singer and colleagues):

  • Availability of the antimicrobial agent and any equipment required for administration
  • The time required for administration by the ED physician and/or nurse
  • Cost-effectiveness of the therapeutic agent
  • Feasible route of administration with acceptable adverse effects associated with the agent
  • Sufficient tissue penetration to allow for effective kill
  • Acceptability of potential failure rate associated with the infection (i.e. infection should not be severe or life-threatening to consider single-dose antimicrobial therapy)
  • Sufficient data in the literature exists to support the use of single-dose antimicrobial therapy for a particular condition
  • Tolerability to treatment based on allergy status
  • Immune status of the patient (i.e. patients with immunocompromised conditions and/or significant comorbidities may not be ideal candidates for single-dose antimicrobial therapy)

Listed below are the infectious conditions where single-dose antimicrobial therapy may be utilized along with the recommended dosing strategy:

Single-Dose Antimicrobial Treatment
Azithromycin 1 g PO
Ceftriaxone 250 mg IM
Primary, secondary, or early latent syphilis
Benzathine penicillin G 2.4 million units IM
Vaginal trichomoniasis
Metronidazole 2 g PO OR Tinidazole 2 g PO
Vulvovaginal candidiasis
Fluconazole 150 mg PO
Acute otitis media
Ceftriaxone 50 mg/kg IM OR Azithromycin 30 mg/kg PO
Streptococcal pharyngitis
Benzathine penicillin G:
< 27 kg: 600, 000 units IM
> 27 kg: 1.2 million units IM

More posts from EM PharmD related to One and Done: Single-Dose Antimicrobials in the ED:

Quick and Dirty Review of Linezolid

I would like to thank Patrick Bridgeman, Pharm.D., BCPS, for providing me with the inspiration to write about this topic.