At-a-glance
• Confirm a compatible syndrome (acute cough + systemic features ± pleuritic pain, focal chest signs) and assess severity.
• Use CRB65 to support site-of-care decisions (plus clinical judgement and SpO2).
• NICE antibiotic regimens for adults are usually 5 days; review response and reconsider diagnosis/complications if not improving.
Initial assessment
- Red flags / severe illness: marked respiratory distress, hypoxia, hypotension, confusion, cyanosis, inability to maintain hydration, or rapidly worsening symptoms → urgent assessment/admission.
- Vitals & severity: RR, HR, BP, temperature, mental state, SpO2 (and baseline target if COPD), hydration and frailty.
- CRB65: Confusion, RR ≥30, BP (SBP <90 or DBP ≤60), Age ≥65. Use to support admission decisions (not in isolation).
- Think “not CAP”: PE, heart failure, asthma/COPD exacerbation without focal signs, aspiration, malignancy, TB, viral illness.
Antibiotic choices for adults (NICE NG250 – typical 5-day courses)
Low-severity CAP (oral):
- Amoxicillin 500 mg three times daily for 5 days (higher doses can be used; see BNF).
- If penicillin allergy or amoxicillin unsuitable (e.g., atypical suspected):
Doxycycline 200 mg day 1, then 100 mg once daily for 4 days (5-day course total), or
Clarithromycin 500 mg twice daily for 5 days, or
Erythromycin (pregnancy) 500 mg four times daily for 5 days.
Moderate-severity CAP (oral):
- Amoxicillin 500 mg three times daily for 5 days and (if atypical pathogens suspected) add clarithromycin 500 mg twice daily for 5 days (or erythromycin 500 mg four times daily in pregnancy).
- Penicillin allergy: Doxycycline 200 mg day 1 then 100 mg once daily for 4 days (5-day course total) or clarithromycin 500 mg twice daily for 5 days.
High-severity CAP: usually hospital-managed. NICE first-line: co-amoxiclav 500/125 mg three times daily PO (or 1.2 g IV three times daily) for 5 days plus clarithromycin 500 mg twice daily PO/IV for 5 days (or erythromycin 500 mg QDS PO in pregnancy).
- Penicillin allergy (high severity): levofloxacin 500 mg twice daily PO/IV for 5 days (consult microbiology if fluoroquinolone not appropriate; note MHRA restrictions/avoid co-administering a corticosteroid with a fluoroquinolone).
Practical notes: Check allergy history, pregnancy/breastfeeding, renal/hepatic function, QT risk and drug interactions. Reassess if no improvement within 48–72 hours.
Follow-up and safety netting
- Review: if clinically not improving within 48–72 hours, reconsider diagnosis, adherence, complications (effusion/empyema), resistant/atypical pathogens, or alternative cause.
- Advise urgent help if: increasing breathlessness, persistent high fever, confusion, chest pain, haemoptysis, new cyanosis, or inability to keep fluids down.
- Consider CXR / further work-up: diagnostic uncertainty, severe features, recurrent pneumonia, immunosuppression, or poor response.
Frequently asked questions
How long is the usual antibiotic course for adult CAP in NICE NG250?
For most adult CAP antibiotic choices in NG250, the listed courses are 5 days (with review and adjustment if not improving or if microbiology suggests otherwise).
When should I think about admission?
Use clinical judgement supported by CRB65, oxygenation (SpO2), haemodynamics, confusion, hydration, frailty/comorbidity, and social support. Any severe illness features should prompt urgent assessment.
What if I suspect atypical pathogens?
NICE includes macrolide add-on (or doxycycline/clarithromycin alternatives) where atypical pathogens are suspected; align with local microbiology advice and patient factors.
Transparency
This page is an educational, clinician-written summary of publicly available NICE guidance intended for trained healthcare professionals. It uses original wording (not copied text) and should be used alongside the full NICE source, local pathways, and clinical judgement. Doses provided are for general reference; always check the BNF/SPC.