Dr Le Khac Bao
Senior Medical Consultant
Viet Lung Clinics
Ho Chi Minh City, Vietnam

Severe community-acquired pneumonia (CAP) often mandates hospital admission and intravenous (IV) antibiotic treatment. However, prolonged IV therapy can predispose patients to complications such as local or systemic infection, contribute to increased antibiotic resistance, and lead to increased healthcare costs.^1-3 Early transition from IV to oral antibiotics, as clinically appropriate, might shorten hospital stays and improve overall patient outcomes.^1,5-6 The decision to switch is complex and relies on specific clinical markers and the patient condition, highlighting the need for evidence-based transition guidelines.^7,8

In this interview, Dr Le Khac Bao from Vietnam, will explore the intricacies of this practice and its implementation within the CAP management landscape.

Q1: Could you elaborate on the specific clinical markers, such as inflammatory biomarkers and radiographic findings, that inform your decision to transition a patient with CAP from IV to oral antibiotic therapy?

The decision to transition from IV to oral antibiotics for CAP is based on clinical judgment and the patient’s response to treatment. After 48 to 72 hours under IV antibiotics, patients should be afebrile and exhibit improvement in respiratory symptoms such as cough, sputum production and chest pain. If these criteria are met, additional tests may not be necessary. In cases where clinical response is unclear, chest X-rays and procalcitonin levels may be assessed. Expanded lesions in chest X-rays and/or increased blood procalcitonin may indicate clinical worsening and require antibiotics escalation. Improvement in chest X-rays typically occurs later than clinical improvement; therefore, radiographic findings are not the primary basis for deciding to switch antibiotics. A decrease in white blood cell count and procalcitonin might be helpful to confirm the ambiguous clinical response and support the decision to switch from IV to oral antibiotics.

Q2: How do pharmacokinetic and pharmacodynamic principles guide your selection of oral antibiotics during the transition from IV therapy?

When switching from IV to oral antibiotics, it is important to choose oral antibiotics that have similar pharmacokinetics and pharmacodynamics to their IV counterparts. Quinolones are notable examples of this approach, as their oral and IV formulations have comparable absorption and effectiveness.

Q3: In what ways does the timing of the transition from IV to oral antibiotics affect the overall recovery trajectory and length of hospital stay for patients with CAP? How do current clinical guidelines support this transition?

Early transition from IV to oral antibiotics, where feasible, shortens hospital stays and improves overall patient centered outcomes. Current CAP management guidelines encourage this early transition. A meta-analysis of six randomised controlled trials (n=1,219) demonstrated that early switch therapy in patients with CAP was associated with a significantly reduced length of hospital stay (weighted mean difference, -3.34 days; 95% CI, -4.42 to -2.25) and fewer drug-related adverse events (OR 0.65, 95% CI: 0.48 to 0.89).⁹ The Infectious Diseases Society of America (IDSA) and the American Thoracic Society (ATS) guidelines recommend switching from IV to oral antibiotics for CAP patients when they show signs of clinical stability, such as being afebrile and having reduced symptoms.¹⁰ These guidelines emphasise that patients should be monitored for clinical improvement before the transition, which can help reduce hospital stay duration and lower the risk of IV-related complications. In Vietnam, similar recommendations are followed, aligning with international guidelines.

Q4: How do local patterns of antibiotic resistance influence your choice of oral antibiotics for patients with CAP? Could you provide specific examples to illustrate this?

The choice of empirical antibiotics for CAP management strongly depends on local antibiotic resistance patterns. An antibiotic is typically chosen empirically only if its local resistance is lower than 20%.¹¹ For example, a study on CAP pathogens in outpatient settings in Vietnam revealed that Streptococcus pneumoniae is the most common cause, and its relevant resistance against quinolone was less than 20%.¹² Therefore, quinolones can be effectively used for patients with mild CAP who can be treated as outpatients. However, for patients with CAP who require hospitalisation, more caution is needed for the choice. If the local resistance against quinolone exceeds 20% for pathogens causing CAP, quinolone would not be recommended to be used as first-line treatment and in monotherapy.

Q5: What are some potential complications that may arise during the transition from IV to oral antibiotics, and how do you manage each of these complications?

One potential complication during the transition from IV to oral antibiotics is gastrointestinal intolerance, such as nausea or vomiting, especially when switching to oral quinolones. Patients are advised to take oral quinolone with a meal to reduce these side effects. Patients are also encouraged to complete the full course of treatment, which is typically of short duration, to ensure its effectiveness despite these side effects.

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