If a patient with a lower respiratory tract infection doesn't improve on Keflex (Cephalexin), should I escalate to Augmentin (Amoxicillin-Clavulanate) or Doxycycline?

From the Guidelines

If a patient with a lower respiratory tract infection isn't improving on Keflex, Augmentin would generally be the preferred escalation option over doxycycline. This recommendation is based on the most recent and highest quality study, which suggests that amoxicillin-clavulanate (Augmentin) is a suitable option for outpatient adults with comorbidities or risk factors for antibiotic-resistant pathogens 1. The typical adult dosing for Augmentin is 875mg/125mg twice daily for 7-10 days. Before switching antibiotics, it's essential to reassess the patient, possibly obtain sputum cultures, and consider chest imaging to confirm the diagnosis and rule out complications. Some key points to consider when making this decision include:

• Local resistance patterns
• Patient comorbidities, such as chronic heart, lung, liver, or renal disease; diabetes mellitus; alcoholism; malignancy; or asplenia
• Recent antibiotic exposure
• Severity of infection, with signs of severe infection (high fever, respiratory distress, hypoxemia) warranting consideration of hospitalization for IV antibiotics and further evaluation rather than oral antibiotic escalation. Doxycycline (100mg twice daily) would be an appropriate alternative if the patient has a penicillin allergy, or if atypical pathogens like Mycoplasma or Chlamydia are suspected, as per the guidelines for healthy outpatient adults without comorbidities or risk factors for antibiotic-resistant pathogens 1.

From the FDA Drug Label

Amoxicillin and Clavulanate Potassium is indicated in the treatment of infections caused by susceptible strains of the designated organisms in the conditions listed below: Lower Respiratory Tract Infections − caused by β-lactamase−producing strains of H. influenzae and M. catarrhalis. The FDA drug label for Augmentin (Amoxicillin-Clavulanate) indicates it is used to treat lower respiratory tract infections. Key Points:

• The patient was initially treated with Keflex (Cephalexin) for a lower respiratory tract infection.
• If the patient does not improve, Augmentin (Amoxicillin-Clavulanate) may be considered as an alternative treatment option, as it is indicated for lower respiratory tract infections caused by β-lactamase−producing strains of H. influenzae and M. catarrhalis 2.
• However, the decision to escalate to Augmentin or Doxycycline should be based on the specific causative organisms and their susceptibility patterns.
• It is essential to consider culture and susceptibility information when selecting or modifying antibacterial therapy.
• In the absence of such data, local epidemiology and susceptibility patterns may contribute to the empiric selection of therapy. The information provided in the label does not directly compare Augmentin to Doxycycline for this specific condition, and therefore, no conclusion can be drawn regarding which one is more suitable for escalation in this scenario. 2

From the Research

Treatment Options for Lower Respiratory Tract Infections

If a patient with a lower respiratory tract infection doesn't improve on Keflex (Cephalexin), the decision to escalate to Augmentin (Amoxicillin-Clavulanate) or Doxycycline depends on various factors, including the causative pathogen, local resistance patterns, and patient-specific considerations.

Efficacy of Augmentin

• Augmentin (Amoxicillin-Clavulanate) is a broad-spectrum antibacterial agent effective against a wide range of pathogens, including those causing lower respiratory tract infections 3.
• It has a favorable pharmacokinetic/pharmacodynamic profile, which contributes to its high bacteriological and clinical efficacy 3.
• Augmentin is included in guidelines and recommendations for the treatment of bacterial sinusitis, acute otitis media, community-acquired pneumonia, and acute exacerbations of chronic bronchitis 3.

Efficacy of Doxycycline

• Doxycycline may represent a reasonable therapeutic alternative for the treatment of certain infections, including those caused by Streptococcal species, in regions with low tetracycline resistance 4.
• Doxycycline has been shown to be effective in the treatment of bacterial infections in chronic bronchitis and asthma, with a similar success rate compared to other antibacterials, including amoxicillin and cephalexin 5.

Comparison of Augmentin and Doxycycline

• There is limited direct comparison between Augmentin and Doxycycline in the treatment of lower respiratory tract infections.
• However, studies suggest that both agents can be effective in the treatment of various infections, with Augmentin having a broader spectrum of activity and Doxycycline being a suitable alternative in certain cases 3, 4, 5.

Considerations for Escalation

• The decision to escalate to Augmentin or Doxycycline should be based on the specific clinical scenario, including the severity of the infection, patient comorbidities, and local resistance patterns.
• It is essential to consider the potential benefits and risks of each treatment option, including the risk of resistance development and adverse effects 3, 6, 4, 5.