Treating CAP with antibiotics should start as soon as possible, within 4 hours after a diagnosis or within 1 hour if sepsis is also suspected.⁸

For cases being treated at home, patients should be advised to seek medical help if:⁸

·       - symptoms worsen rapidly or significantly, or

·      - symptoms do not start to improve within 3 days, or

·      - the person becomes systemically very unwell.

If the patient is not responding, reassessment should prompt consideration of non-bacterial causes such as flu, and sending a sputum sample for microbiological testing to see if the antibiotic being used is appropriate.

Hospital referral is necessary for complications (such as suspected sepsis or cardiorespiratory failure), antimicrobial resistance, or the patient cannot take antibiotics orally.

NICE splits its antibiotic selection recommendations for CAP into those for adults aged 18 years and above and for children, and by severity (using the CRB65/CURB65 score for adults where possible). Children under 1 month should be referred to a paediatric specialist.

Depending on severity, first line options are based on amoxicillin or co amoxiclav, with second line options being a macrolide (erythromycin or clarithromycin) or a tetracycline (doxycycline) for penicillin allergy or if atypical pathogens are suspected as these are less likely to respond to beta-lactam antibiotics. Initial treatment is usually for five days.⁸ (See Table 2)

Levofloxacin is reserved as a second line option for high-risk infection in adults, in line with the MHRA expectation that systemic fluoroquinolones should only be used when other commonly antibiotics are inappropriate.²⁰

Table 2: Antibiotic recommendations for community-acquired pneumonia

(adapted from NICE guidance NG 138,⁸ section 1.2)