Antibiotic Options: What's the Diagnosis - January 2023

Column Author: Chia-Chi Angela Fu, MD | Internal Medicine-Pediatrics Resident, PGY-2

Column Editor: Joe Julian, MD, MPHTM | Hospitalist, Internal Medicine-Pediatrics; Clinical Associate Professor, Internal Medicine & Pediatrics

A 2-year-old boy is brought to the emergency department by his mother for six days of fever with a maximum temperature of 103 F. Symptoms started at the beginning of the week with cough and congestion that seemed to be getting better but have worsened over the last two days. He also has had decreased appetite, one episode of non-bloody, non-bilious emesis, and a few loose, non-bloody stools since yesterday. No one else at home is sick with similar symptoms. He is currently in child care but sometimes stays with his grandmother. He is up to date on immunizations and has no notable past medical history or drug allergies. 

On exam he is febrile to 40.1 C, tachycardic and tachypneic. Oxygen saturations are appropriate on ambient air. He interacts with you on physical exam and looks generally well but is fatigued-appearing. Auscultation is notable for crackles and diminished lung sounds in the right upper lung fields. Chest radiography is obtained to confirm clinical findings with the images below: 

You are considering prescribing amoxicillin, but every pharmacy you called in the last few days reports no stock of the suspension for at least a month. What would be your next choice for oral antibiotics? 

*Patient weight is 13.2 kg, assume below dosing is correct 

1. Amoxicillin 500 mg tablet, give 1.25 tablets crushed and mixed in juice twice daily 
2. Amoxicillin 250 mg chewable, give 2.5 chews twice daily 
3. No antibiotics needed as this is likely a viral pneumonia 
4. Cefdinir 250 mg/5 mL liquid, give 5 mL twice daily 
5. Azithromycin 200 mg/5 mL liquid, give 3 mL once then 1.5 mL once a day 

Answer: B  

Medication in the pediatric population generally has more considerations than in the adult population. Not only is medication based on weight, but health care providers also need to consider the method of administration as younger populations do not tolerate pills or medications that are unpalatable to children. The main administration of medication for pediatric patients is liquid as it is easy to swallow and can be made into syrups. However, this choice assumes that it is possible to take the medications and compound them into a liquid form that is palatable to taste.  

Amoxicillin is a common antibiotic used to treat several infections including community-acquired pneumonia, such as the above case. It is made in liquid formulations of 125 mg/5 mL, 250 mg/5 mL and 400 mg/5 mL. Unfortunately, with the ongoing shortage of amoxicillin suspension, we must keep in mind alternatives to prescribe instead. Beta-lactams continue to be the preferred antibiotic of choice as there is not high prevalence of penicillin resistance in our region. 

To help with other forms of administration, tablets (amoxicillin has 500 g and 875 mg tablets) can be split in half, crushed and mixed with semi-solids or liquids. However, their palatability is limited by bitterness. Capsules (amoxicillin has 250 mg and 500 mg capsules) can also be opened and mixed with liquids and semisolids (e.g., applesauce). Lastly, there is chewable amoxicillin dosed at 250 mg, which can also be split in half for patients who are able to take chewable medications. Dosing these medications can be a little more challenging because it is weight-based and subject to rounding error (up to 10% is acceptable when adjusting dosing to obtain an easily dispensable dose). 

When newer cephalosporins were introduced, several studies in the early 2000s supported the use of oral cephalosporins for common pediatric illnesses such as community-acquired pneumonia. However, not all cephalosporins are created equal nor are they interchangeable. Cefpodoxime is an appropriate alternative for community-acquired bacterial pneumonia. Cefdinir does not achieve sufficient pulmonary concentrations to treat pneumonia and additionally has poor activity against Streptococcus pneumoniae, the most common bacterial etiology of pneumonia. 

Based on clinical examination, history and radiography, the child in this case very likely has a bacterial pneumonia, so no treatment would be inappropriate. Azithromycin has fallen out of favor given the high rate of resistance in S. pneumoniae, and this patient lacks the typical demographics or radiography to suggest an atypical pneumonia. Chewable medication options are patient dependent but are a feasible option for those 2 years and older. Chewable tablets can also be split. Splitting a tablet into quarters creates high risk for inconsistent dosing and dosing error given lack of pill scoring and is not the best option. 

Additional options for this patient: 

-Amoxicillin 250 mg tablet, give 2.5 tablets crushed and mixed in juice twice daily 
-Amoxicillin-clavulanate 600 mg-42.9 mg/5 mL liquid, give 5 mL twice daily 
-Cefpodoxime 50 mg/5 mL liquid, give 7 mL twice daily 

Takeaway Points 

1. Beta-lactams are best for treatment of pneumonia; not all cephalosporins are created equal 
2. Alternative deliveries of amoxicillin (crushing tablets, opening capsules, chewables) should be considered with a 10% dosage adjustment as needed for dispensing convenience 
3. Azithromycin (pneumococcal resistance) and cefdinir (inadequate penetration + pneumococcal resistance) are not adequate therapy for bacterial pneumonia 

Prescribing Options/Tips 

Amoxicillin Shortage: Antibiotic Options for Common Pediatric Conditions by the American Academy of Pediatrics 

Outpatient Antibiotic Handbook by Children’s Mercy Antimicrobial Stewardship Program 

Resources: 

1. American Academy of Pediatrics. Table 4.12. Systems-based treatment table. In: Kimberlin DW, Barnett ED, Lynfield R, Sawyer MH, eds. Red Book: 2021-2024 Report of the Committee on Infectious Diseases. 32nd ed. American Academy of Pediatrics; 2021:990-1003. 
2. Bradshaw Mitchell MJ, Edwards CJ, et al. Medication palatability affects physician prescribing preferences for common pediatric conditions. Acad Emerg Med. 2016;23(11):1243-1247. 
3. Leung AKC, Wong AHC, Hon KL. Community-acquired pneumonia in children. Recent Pat Inflamm Allergy Drug Discov. 2018;12(2):136-144. 
4. Murphy ME, Powell E, Courter J, Mortensen JE. Predicting oral beta-lactam susceptibilities against Streptococcus pneumoniae. BMC Infect Dis. 2021;21(1):679.